Metal-organic materials and method for preparation
09611218 ยท 2017-04-04
Assignee
Inventors
- Milko E. VAN DER BOOM (Rishon Lezion, IL)
- Michal LAHAV (Rehovot, IL)
- Renata Balgley (Rehovot, IL)
- Sreejith Shankar Poopanal (Rehovot, IL)
Cpc classification
B01J20/226
PERFORMING OPERATIONS; TRANSPORTING
B01D2253/204
PERFORMING OPERATIONS; TRANSPORTING
C07F19/00
CHEMISTRY; METALLURGY
C07D213/06
CHEMISTRY; METALLURGY
B01D53/02
PERFORMING OPERATIONS; TRANSPORTING
C08G83/00
CHEMISTRY; METALLURGY
International classification
C07D213/06
CHEMISTRY; METALLURGY
B01D53/02
PERFORMING OPERATIONS; TRANSPORTING
C07F15/00
CHEMISTRY; METALLURGY
C08L101/00
CHEMISTRY; METALLURGY
C07F19/00
CHEMISTRY; METALLURGY
Abstract
The present invention provides metal-organic materials, more specifically organometallic polymers, comprising polypyridyl organic ligands such as tetrakis(4-(pyridin-4-ylethynyl)phenyl)methane, tetrakis(4-(2-(pyridin-4-yl)vinyl)phenyl)methane,3,5,7-tetrakis(4-(pyridin-4-ylethynyl)phenyl)adamantane or 1,3,5,7-tetrakis(4-(2-(pyridine-4-yl)vinyl)phenyl)adamantine, and metal ions structurally coordinated with said ligands, and having three-dimensional crystalline micro or sub-micro structure; as well as a method for the preparation thereof. These metal-organic materials are useful as adsorbents in processes for gas adsorption or separation.
Claims
1. A metal-organic material, having a three-dimensional (3D) crystalline micro or sub-micro structure, comprising at least two ligands, at least two metal ions structurally coordinated with said ligands, and counter anions, wherein each one of the ligands is of the general formula I:
R.sub.1(R.sub.2R.sub.3R.sub.4).sub.4,I wherein R.sub.1 is C or adamantane-1,3,5,7-tetrayl; R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.8)alkylene, (C.sub.2-C.sub.8)alkenylene, (C.sub.2-C.sub.8)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OR.sub.6, CN, COR.sub.6, COOR.sub.6, CON(R.sub.6).sub.2, OCOOR.sub.6, OCON(R.sub.6).sub.2, (C.sub.1-C.sub.4)alkyl, O(C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkylene-COOR.sub.6, N(R.sub.6).sub.2, NO.sub.2, SR.sub.6, SO.sub.2R.sub.6, or S(O)R.sub.6, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.4alkyl)-, N(C.sub.6-C.sub.10aryl)-, or (C.sub.6-C.sub.10)arylene-diyl-, wherein R.sub.6 each independently is H, (C.sub.1-C.sub.4)alkyl, (C.sub.2-C.sub.4)alkenyl or (C.sub.2-C.sub.4)alkynyl; R.sub.4 each independently is a pyridyl of the formula II, 2,2-bipyridyl of the formula III, or 2,2:6,2-terpyridyl of the formula IV, linked through a carbon atom thereof; and ##STR00006## R.sub.5 each independently is H, COOH, CN, OH, or NH.sub.2.
2. The metal-organic material of claim 1, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.8)alkylene, (C.sub.2-C.sub.8)alkenylene, (C.sub.2-C.sub.8)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OH, CN, COH, COOH, CONH.sub.2, OCOOH, OCONH.sub.2, (C.sub.1-C.sub.4)alkyl, O(C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkylene-COOH, NH.sub.2, NO.sub.2, SH, SO.sub.2H, or S(O)H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.4alkyl)-, N(C.sub.6-C.sub.10aryl)-, or (C.sub.6-C.sub.10)arylene-diyl-.
3. The metal-organic material of claim 2, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with halogen, OH, CN, COH, COOH, CONH.sub.2, OCOOH, OCONH.sub.2, (C.sub.1-C.sub.2)alkyl, O(C.sub.1-C.sub.2)alkyl, (C.sub.1-C.sub.2)alkylene-COOH, NH.sub.2, NO.sub.2, SH, SO.sub.2H, or S(O)H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.2alkyl)-, N(C.sub.6aryl)-, or (C.sub.6)arylene-diyl-.
4. The metal-organic material of claim 3, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl.
5. The metal-organic material of claim 4, wherein (i) one of R.sub.2 and R.sub.3 is absent and another of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; (ii) one of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and another of R.sub.2 and R.sub.3 is arylene-diyl, or heteroarylene-diyl; or (iii) both R.sub.2 and R.sub.3 are absent.
6. The metal-organic material of claim 5, wherein R.sub.2 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and R.sub.3 is (C.sub.6)arylene-diyl; or R.sub.2 is (C.sub.6)arylene-diyl, and R.sub.3 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene.
7. The metal-organic material of claim 1, wherein R.sub.4 each independently is a pyridyl of the formula II, wherein R.sub.5 each independently is H, COOH, CN, OH, or NH.sub.2, preferably H or COOH.
8. The metal-organic material of claim 1, wherein R.sub.1 is C or adamantane-1,3,5,7-tetrayl; R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OH, CN, COH, COOH, CONH.sub.2, OCOOH, OCONH.sub.2, (C.sub.1-C.sub.2)alkyl, O(C.sub.1-C.sub.2)alkyl, (C.sub.1-C.sub.2)alkylene-COOH, NH.sub.2, NO.sub.2, SH, SO.sub.2H, or S(O)H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.2alkyl)-, N(C.sub.6aryl)-, or (C.sub.6)arylene-diyl-; R.sub.4 each independently is pyridyl of the formula II; and R.sub.5 each independently is H, COOH, CN, OH, or NH.sub.2, preferably H or COOH.
9. The metal-organic material of claim 8, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; R.sub.4 is a pyridyl of the formula II linked through the carbon atom para to the nitrogen atom; and R.sub.5 is H or COOH.
10. The metal-organic material of claim 9, wherein (i) one of R.sub.2 and R.sub.3 is absent and another of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; (ii) one of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and another of R.sub.2 and R.sub.3 is arylene-diyl, or heteroarylene-diyl; or (iii) both R.sub.2 and R.sub.3 are absent.
11. The metal-organic material of claim 10, wherein R.sub.2 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and R.sub.3 is (C.sub.6)arylene-diyl; or R.sub.2 is (C.sub.6)arylene-diyl, and R.sub.3 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene.
12. The metal-organic material of claim 11, wherein R.sub.2 is (C.sub.6)arylene-diyl; and R.sub.3 is (C.sub.2)alkenylene or (C.sub.2)alkynylene.
13. The metal-organic material of claim 12, wherein: (i) R.sub.1 is C, and each one of said ligands is tetrakis(4-(pyridin-4-ylethynyl) phenyl)methane or tetrakis(4-(2-(pyridin-4-yl) vinyl)phenyl) methane, herein identified ligands L1 and L2, respectively; or (ii) R.sub.1 is adamantane-1,3,5,7-tetrayl, and each one of said ligands is 1,3,5,7-tetrakis(4-(pyridin-4-ylethynyl)phenyl)adamantane or 1,3,5,7-tetrakis(4-(2-(pyridin-4-yl)vinyl)phenyl)adamantane, herein identified ligands L3 and L4, respectively.
14. The metal-organic material of claim 1, wherein said metal ions are ions of a transition metals selected from Os, Ru, Fe, Pt, Pd, Ni, Ir, Rh, Zn, Co, Cu, Re, Tc, Mn, V, Nb, Ta, Hf, Zr, Cr, Mo, W, Ti, Sc, Ag, Au, Y, or a combination thereof.
15. The metal-organic material of claim 14, wherein said transition metal is Ni, Cu, Pd, Zn, or a combination thereof.
16. The metal-organic material of claim 1, wherein said counter anions are selected from inorganic anions, organic anions, or a combination thereof.
17. The metal-organic material of claim 16, wherein said inorganic anions are selected from Cl.sup., Br.sup., I.sup., NO.sub.3.sup., PF.sub.6.sup., BF.sub.4.sup., OH.sup., ClO.sub.4.sup., SO.sub.3.sup., or CN.sup.; and said organic anions are selected form alkylCOO.sup., preferably acetoxy (OAc), CF.sub.3COO.sup., arylCOO.sup., trifluoromethanesulfonate (triflate, OTf), citrate.
18. The metal-organic material of claim 1, wherein at least one of said metal ions is structurally coordinated between two of said at least two ligands.
19. The metal-organic material of claim 1, wherein said crystalline micro or sub-micro structure has a geometrical shape.
20. The metal-organic material of claim 13, comprising ligands each being the herein identified ligand L1 and transition metal ions structurally coordinated with nitrogen atoms of said ligands, wherein: (i) said transition metal ions are Ni(II) ions, said counter anions are Cl.sup., and said metal-organic material has the chemical formula (NiCl.sub.2N.sub.2C.sub.26.5H.sub.16).sub.n(solvents).sub.m; or (ii) said transition metal ions are Ni(II) ions, said counter anions are Br.sup., and said metal-organic material has the chemical formula (NiBr.sub.2N.sub.2C.sub.26.5H.sub.16).sub.n(solvents).sub.m, wherein n is an integer of at least 4, and said metal-organic material has a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules, wherein (m0).
21. The metal-organic material of claim 13, comprising ligands each being the herein identified ligand L2 and transition metal ions structurally coordinated with nitrogen atoms of said ligands, wherein: (i) said transition metal ions are Ni(II) ions, said counter anions are Cl.sup., and said metal-organic material has the chemical formula (NiCl.sub.2N.sub.2C.sub.26.5H.sub.2).sub.n(solvents).sub.m; (i) said transition metal ions are Ni(II) ions, said counter anions are Br.sup., and said metal-organic material has the chemical formula (NiBr.sub.2N.sub.2C.sub.26.5H.sub.2).sub.n(solvents).sub.m; (ii) said transition metal ions are Cu(II) ions, said counter anions are Cl.sup., and said metal-organic material has the chemical formula (CuCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (iii) said transition metal ions are Cu(II) ions, said counter anions are Br.sup., and said metal-organic material has the chemical formula (CuBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (iv) said transition metal ions are Cu(II) ions, said counter anions are NO.sub.3.sup., and said metal-organic material has the chemical formula (Cu(NO.sub.3).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (v) said transition metal ions are Cu(II) ions, said counter anions are OTf.sup., and said metal-organic material has the chemical formula (Cu(OTf).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (vi) said transition metal ions are Pd(II) ions, said counter anions are Cl.sup., and said metal-organic material has the chemical formula (PdCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (vii) said transition metal ions are Zn(II) ions, said counter anions are OAc.sup., and said metal-organic material has the chemical formula (Zn(OAc).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; (viii) said transition metal ions are Zn(II) ions, said counter anions are Cl.sup., and said metal-organic material has the chemical formula (ZnCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m; or (ix) said transition metal ions are Zn(II) ions, said counter anions are Br.sup., and said metal-organic material has the chemical formula (ZnBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n(solvents).sub.m, wherein n is an integer of at least 4, and said metal-organic material has a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules, wherein (m0).
22. A method for the preparation of a metal-organic material according to claim 1, comprising the steps of: (i) providing (a) an organic solution or suspension of a metal salt consisting of anions and said metal ions; and (b) an organic solution or suspension of said ligands, in a pressure vessel such as a sealable glass pressure tube; (ii) sealing and keeping said pressure vessel for a period of time with exclusion of light and without stirring, thereby reacting said metal ions with said ligands to obtain said metal-organic material as a precipitate; and (iii) collecting said precipitate; wherein step (ii) is carried out while heating said pressure vessel to a temperature ranging from 60 C. to 120 C., for the whole said period of time or a part thereof, and then gradually cooling said pressure vessel.
23. The method of claim 22, wherein said pressure vessel is a glass pressure vessel or glass pressure tube.
24. The method of claim 22, wherein the organic solvent in said organic solution or suspension each independently is chloroform, dimethylformamide (DMF), an alkanol, DMSO, acetonitrile, ethylene glycol, toluene, benzene, ethylbenzene, ether (diethyl ether), or an alkane.
25. The method of claim 22, wherein said period of time in step (ii) is from about 1 to about 10 days or more.
26. The method of claim 22, wherein steps (i)-(ii) are carried out under inert conditions.
27. The method of claim 22, wherein the metal-organic material obtained has a three-dimensional crystalline micro or sub-micro structure.
28. The method of claim 27, wherein said crystalline micro or sub-micro structure has a geometrical shape.
29. The method of claim 28, wherein said geometrical shape is affected by reaction components and/or the reaction conditions or parameters in steps (ii).
30. The method of claim 29, wherein said reaction components are one or more of said metal ions, anions, and organic solvents; and said reaction conditions or parameters are one or more of said temperature, period of time, and cooling rate.
31. A process for gas adsorption, gas separation, gas purification or gas storage, comprising the steps of: providing an adsorbent comprising the metal-organic material according to claim 1; and adsorbing said gas to said adsorbent.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(32)
(33)
(34)
(35)
(36)
(37)
(38)
(39)
(40)
(41)
(42)
(43)
(44)
(45)
(46)
(47)
(48)
(49)
(50)
(51)
(52)
(53)
(54)
(55)
(56)
DETAILED DESCRIPTION OF THE INVENTION
(57) In one aspect, the present invention provides a metal-organic material as defined above, i.e., a metal-organic material comprising at least two ligands each of the general formula I as defined above, at least two metal ions structurally coordinated with said ligands, and counter anions.
(58) The term metal-organic material or metal-organic framework (MOF) as used herein refers to a particular type of a coordination polymer, more specifically an organometallic polymer, containing metal cations, preferably transition metal cations, coordinated to organic ligands each of the general formula I to form one-, two-, or three-dimensional structures that can be porous, wherein the choice of metal cation and organic ligand dictates the structure and hence properties of the MOF. More particularly, the MOF is a coordination network with organic ligands containing potential voids, wherein the term coordination network refers to a coordination oligomer extending, through repeating coordination entities, either in one dimension but with cross-links between two or more individual chains, loops, or spiro-links, or in two or three dimensions (see also Biradha et al., 2009).
(59) The term halogen, as used herein, includes fluoro, chloro, bromo, and iodo.
(60) The term alkane, as used herein, refers to a straight or branched, or cyclic (including bicyclic), saturated hydrocarbon having preferably 5-14, carbon atoms, and includes, e.g., pentane, hexane, cyclohexane, heptane, cycloheptane, octane, cyclooctane, nonane, decane, decalin, and the like.
(61) The term alkanol, as used herein, refers to an alkane having preferably 1-10 carbon atoms and containing a hydroxy/alcohol functional group (OH) in place of a hydrogen atom, and includes, e.g., methanol, ethanol, isopropanol, n-butanol, sec-butanol, isobutanol, pentanol, hexanol, and the like.
(62) The term alkyl, as used herein, typically means a straight or branched hydrocarbon radical having preferably 1-8, more preferably 1-4, carbon atoms, and includes, e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, and the like.
(63) The term alkylene, as used herein, refers to a linear divalent hydrocarbon chain having preferably 1-8 carbon atoms and includes, e.g., methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and the like. The terms alkenylene and alkynylene typically mean linear divalent hydrocarbon radicals having preferably 2-8 carbon atoms and at least one double or triple bond, respectively. Non-limiting examples of such alkenylenes include ethenylene, 1,3-propenylene, 1,4-but-1-enylene, 1,4-but-2-enylene, 1,4-but-3-enylene, 1,5-pent-1-enylene, 1,5-pent-2-enylene, 1,5-pent-3-enylene, 1,5-pent-4-enylene, 1,6-hex-1-enylene, 1,6-hex-2-enylene, 1,6-hex-3-enylene, 1,6-hex-4-enylene, 1,6-hex-5-enylene, 1,7-hept-1-enylene, 1,7-hept-2-enylene, 1,7-hept-3-enylene, 1,7-hept-4-enylene, 1,7-hept-5-enylene, 1,7-hept-6-enylene, 1,8-oct-1-enylene, 1,8-oct-2-enylene, 1,8-oct-2-enylene, 1,8-oct-3-enylene, 1,8-oct-4-enylene, 1,8-oct-5-enylene, 1,8-oct-6-enylene, 1,8-oct-7-enylene, and the like; and examples of such alkynylenes include, without limiting, ethynylene, 1,3-propynylene, 1,4-but-1-ynylene, 1,4-but-2-ynylene, 1,4-but-3-ynylene, 1,5-pent-1-ynylene, 1,5-pent-2-ynylene, 1,5-pent-3-ynylene, 1,5-pent-4-ynylene, 1,6-hex-1-ynylene, 1,6-hex-2-ynylene, 1,6-hex-3-ynylene, 1,6-hex-4-ynylene, 1,6-hex-5-ynylene, 1,7-hept-1-ynylene, 1,7-hept-2-ynylene, 1,7-hept-3-ynylene, 1,7-hept-4-ynylene, 1,7-hept-5-ynylene, 1,7-hept-6-ynylene, 1,8-oct-1-ynylene, 1,8-oct-2-ynylene, 1,8-oct-2-ynylene, 1,8-oct-3-ynylene, 1,8-oct-4-ynylene, 1,8-oct-5-ynylene, 1,8-oct-6-ynylene, 1,8-oct-7-ynylene, and the like.
(64) The term cycloalkylene, as used herein, typically means a mono- or bicyclic saturated divalent hydrocarbon radical having preferably 3-10 carbon atoms such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclodecylene, bicyclo[3.2.1]octane-diyl, bicyclo[2.2.1]heptane-diyl, and the like. The term heterocycloalkylene refers to a cycloalkylene, in which at least one of the ring carbon atoms is replaced by a heteroatom selected from N, O or S.
(65) The term aryl, as used herein, denotes an aromatic carbocyclic group, preferably having 6-14 carbon atoms, consisting of a single ring or multiple rings either condensed or linked by a covalent bond such as, but not limited to, phenyl, naphthyl, phenanthryl, and biphenyl. The term arylene-diyl refers to a divalent group derived from an arene by removal of a hydrogen atom from two ring carbon atoms. Non-limiting examples of arylene-diyls include benzene-1,3-diyl, benzene-1,4-diyl, naphthalene-diyl, phenanthrene-2,7-diyl, biphenyl-4,4-diyl, and the like.
(66) The term heteroarylene-diyl refers to a divalent group derived from a mono- or polycyclic heteroaromatic ring containing one to three, preferably 1-2, heteroatoms selected from the group consisting of N, O and S, by removal of a hydrogen atom from two ring atoms. When the heteroarylene-diyl is a monocyclic heteroaromatic ring, it is preferably a divalent group of a 5-6-membered ring such as, but not limited to, pyrrole-2,5-diyl, pyrrole-3,5-diyl, furane-2,5-diyl, furane-3,5-diyl, thiophene-2,5-diyl, thiophene-3,5-diyl, thiazine-2,5-diyl, thiazine-3,6-diyl, pyrazole-1,3-diyl, pyrazole-1,4-diyl, pyrazole-3,5-diyl, pyrazine-2,5-diyl, pyrazine-2,6-diyl, imidazole-1,4-diyl, imidazole-2,4-diyl, imidazole-2,5-diyl, oxazole-2,4-diyl, oxazole-2,5-diyl, isoxazole-3,5-diyl, thiazole-2,4-diyl, thiazole-2,5-diyl, isothiazole-3,5-diyl, pyridine-2,4-diyl, pyridine-3,6-diyl, pyrimidine-2,4-diyl, pyrimidine-2,5-diyl, 1,2,3-triazine-4,6-diyl, 1,3,4-triazine-2,5-diyl, 1,3,4-triazine-2,6-diyl, 1,3,5-triazine-2,4-diyl, and the like. Examples of polycyclic heteroarylene-diyls composed of two rings include, without being limited to, benzofurane-2,5-diyl, benzofurane-2,6-diyl, isobenzofurane-2,4-diyl, isobenzofurane-2,5-diyl, benzothiene-2,5-diyl, benzothiene-2,6-diyl, indole-2,5-diyl, indole-2,6-diyl, quinoline-2,6-diyl, quinoline-2,7-diyl, quinoline-3,6-diyl, quinoline-3,7-diyl, isoquinoline-3,6-diyl, isoquinoline-3,7-diyl, imidazo[1,2-a]pyridine-2,6-diyl, imidazo[1,2-a]pyridine-2,7-diyl, benzimidazole-2,5-diyl, benzimidazole-2,6-diyl, benzthiazole-2,5-diyl, benzthiazole-2,6-diyl, benzoxazole-2,5-diyl, benzoxazole-2,6-diyl, pyrido[1,2-a]pyrimidine-2,7-diyl, pyrido[1,2-a]pyrimidine-2,8-diyl, pyrido[1,2-a]pyrimidine-3,7-diyl, pyrido[1,2-a]pyrimidine-3,7-diyl, 1,3-benzodioxin-2,6-diyl, 1,3-benzodioxin-2,7-diyl, and the like.
(67) The alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OR.sub.6, CN, COR.sub.6, COOR.sub.6, CON(R.sub.6).sub.2, OCOOR.sub.6, OCON(R.sub.6).sub.2, (C.sub.1-C.sub.4)alkyl, O(C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkylene-COOR.sub.6, N(R.sub.6).sub.2, NO.sub.2, SR.sub.6, SO.sub.2R.sub.6, or S(O)R.sub.6, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more, e.g., one or two, identical or different heteroatoms selected from S, O or N, and/or at least one group, e.g., one, two or three groups, each independently selected from NN, NHCO, CONH, N(C.sub.1-C.sub.4alkyl)-, N(C.sub.6-C.sub.10aryl)-, or (C.sub.6-C.sub.10)arylene-diyl-, wherein R.sub.6 each independently is H, (C.sub.1-C.sub.4)alkyl, (C.sub.2-C.sub.4)alkenyl or (C.sub.2-C.sub.4)alkynyl.
(68) In certain embodiments, the metal-organic material of the present invention is a material of the general formula I as defined above, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.8)alkylene, (C.sub.2-C.sub.8)alkenylene, (C.sub.2-C.sub.8)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OR.sub.6, CN, COR.sub.6, COOR.sub.6, CON(R.sub.6).sub.2, OCOOR.sub.6, OCON(R.sub.6).sub.2, (C.sub.1-C.sub.4)alkyl, O(C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkylene-COOR.sub.6, N(R.sub.6).sub.2, NO.sub.2, SR.sub.6, SO.sub.2R.sub.6, or S(O)R.sub.6, wherein R.sub.6 is H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.4alkyl)-, N(C.sub.6-C.sub.10aryl)-, or (C.sub.6-C.sub.10)arylene-diyl-.
(69) In certain particular such embodiments, R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with halogen, OH, CN, COH, COOH, CONH.sub.2, OCOOH, OCONH.sub.2, (C.sub.1-C.sub.2)alkyl, O(C.sub.1-C.sub.2)alkyl, (C.sub.1-C.sub.2)alkylene-COOH, NH.sub.2, NO.sub.2, SH, SO.sub.2H, or S(O)H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.2alkyl)-, N(C.sub.6aryl)-, or (C.sub.6)arylene-diyl-.
(70) In more particular such embodiments, the metal-organic material of the present invention is a material of the general formula I, wherein R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl, e.g., wherein (i) one of R.sub.2 and R.sub.3 is absent and another of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; (ii) one of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and another of R.sub.2 and R.sub.3 is arylene-diyl, or heteroarylene-diyl; or (iii) both R.sub.2 and R.sub.3 are absent. Certain specific such embodiments are those wherein R.sub.2 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and R.sub.3 is (C.sub.6)arylene-diyl; or R.sub.2 is (C.sub.6)arylene-diyl, and R.sub.3 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene.
(71) In certain embodiments, the metal-organic material of the present invention is a material of the general formula I as defined above, wherein R.sub.4 each independently is a pyridyl of the formula II, wherein R.sub.5 each independently is H, COOH, CN, OH, or NH.sub.2, preferably H or COOH.
(72) In certain embodiments, the metal-organic material of the present invention is a material of the general formula I as defined above, wherein R.sub.1 is C or adamantane-1,3,5,7-tetrayl; R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl, heteroarylene-diyl, or NN, wherein said alkylene, alkenylene, alkynylene, cycloalkylene, heterocycloalkylene, arylene-diyl and heteroarylene-diyl may optionally be substituted with one or more groups each independently selected from halogen, OR.sub.6, CN, COR.sub.6, COOR.sub.6, CON(R.sub.6).sub.2, OCOOR.sub.6, OCON(R.sub.6).sub.2, (C.sub.1-C.sub.4)alkyl, O(C.sub.1-C.sub.4)alkyl, (C.sub.1-C.sub.4)alkylene-COOR.sub.6, N(R.sub.6).sub.2, NO.sub.2, SR.sub.6, SO.sub.2R.sub.6, or S(O)R.sub.6, wherein R.sub.6 is H, or said alkylene, alkenylene and alkynylene may optionally be interrupted by one or more identical or different heteroatoms selected from S, O or N, and/or at least one group selected from NN, NHCO, CONH, N(C.sub.1-C.sub.2alkyl)-, N(C.sub.6aryl)-, or (C.sub.6)arylene-diyl-; R.sub.4 each independently is pyridyl of the formula II; and R.sub.5 each independently is H, COOH, CN, OH, or NH.sub.2, preferably H or COOH.
(73) In certain particular such embodiments, R.sub.2 and R.sub.3 each independently is absent, or selected from (C.sub.1-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; R.sub.4 is a pyridyl of the formula II linked through the carbon atom para to the nitrogen atom; and R.sub.5 is H or COOH. In more particular such embodiments, the metal-organic material of the present invention is a material of the general formula I, wherein (i) one of R.sub.2 and R.sub.3 is absent and another of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene, (C.sub.2-C.sub.4)alkynylene, arylene-diyl, or heteroarylene-diyl; (ii) one of R.sub.2 and R.sub.3 is (C.sub.2-C.sub.4)alkylene, (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and another of R.sub.2 and R.sub.3 is arylene-diyl, or heteroarylene-diyl; or (iii) both R.sub.2 and R.sub.3 are absent, e.g., wherein R.sub.2 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene, and R.sub.3 is (C.sub.6)arylene-diyl; or R.sub.2 is (C.sub.6)arylene-diyl, and R.sub.3 is (C.sub.2-C.sub.4)alkenylene or (C.sub.2-C.sub.4)alkynylene. Certain specific such embodiments are those wherein R.sub.2 is (C.sub.6)arylene-diyl; and R.sub.3 is (C.sub.2)alkenylene or (C.sub.2)alkynylene, i.e., metal-organic materials comprising at least two metal ions structurally coordinated with at least two polypyridyl ligands each of the general formula I, consisting of C or adamantane-1,3,5,7-tetrayl linked to four identical arms each being (4-(2-(pyridin-4-yl)vinyl)phenyl) or (4-(pyridin-4-ylethynyl)phenyl), respectively.
(74) In specific embodiments, the metal-organic material of the present invention is a material of the general formula I, wherein (i) R.sub.1 is C, and each one of said ligands is tetrakis(4-(pyridin-4-ylethynyl)phenyl)methane or tetrakis(4-(2-(pyridin-4-yl)vinyl)phenyl)methane, herein identified ligands L1 and L2, respectively; or (ii) R.sub.1 is adamantane-1,3,5,7-tetrayl, and each one of said ligands is 1,3,5,7-tetrakis(4-(pyridin-4-ylethynyl)phenyl)adamantane or 1,3,5,7-tetrakis(4-(2-(pyridin-4-yl)vinyl)phenyl)adamantane, herein identified ligands L3 and L4, respectively (see Appendix).
(75) In certain embodiments, the metal ions comprised within the metal-organic material of the present invention are ions of a transition metal such as Os, Ru, Fe, Pt, Pd, Ni, Ir, Rh, Zn, Co, Cu, Re, Tc, Mn, V, Nb, Ta, Hf, Zr, Cr, Mo, W, Ti, Sc, Ag, Au, Y, or a combination thereof. In particular such embodiments, the metal ions are ions of one or more, i.e., a combination, of Ni, Cu, Pd or Zn.
(76) In certain embodiments, the counter anions comprised within the metal-organic material of the present invention are selected from inorganic anions, organic anions, or a combination thereof. Examples of inorganic anions include, without being limited to, F.sup., Cl.sup., Br.sup., I.sup., NO.sub.3.sup., PF.sub.6.sup., BF.sub.4.sup., OH.sup., ClO.sub.4.sup., SO.sub.3.sup., and CN.sup.; and non-limiting examples of organic anions include alkylCOO.sup., preferably acetoxy (OAc), CF.sub.3COO.sup., arylCOO.sup., trifluoromethanesulfonate (triflate, OTf).
(77) As defined above, the metal-organic material of the present invention is a particular type of a coordination polymer containing metal ions, preferably transition metal ions, coordinated to organic ligands each of the general formula I to form one-, two-, or three-dimensional structures. In certain embodiments, the metal-organic material of the present invention comprises at least one of said metal ions structurally coordinated between two of said at least two ligands.
(78) In certain embodiments, the metal-organic material of the present invention comprises metal ions coordinated to organic ligands each of the general formula I to form a three-dimensional (3D) structure. In particular such embodiments, the metal-organic material of the invention has a 3D crystalline micro or sub-micro structure, more particularly wherein said crystalline micro or sub-micro structure has a geometrical shape, e.g., a brick-like microstructure. Examples of 3D crystalline geometric shape include, without being limited to, hexagonal, spherical, stella-octangula, and flower-like shape.
(79) MOFs having 3D structures in general and such MOFs according to the present invention in particular, are porous and may thus further comprise solvent molecules, also referred to as guest molecules, left from the preparation process and confined within the pores of the 3D structure. As the pores of the MOFs are stable during elimination of those solvent molecules, such MOFs can be used as adsorbents in processes for gas adsorption, e.g., H.sub.2, CO, CO.sub.2 or methane adsorption, or gas separation and/or purification, e.g., separation of CO.sub.2 from methane.
(80) In one specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L1, Ni(II) ions structurally coordinated with nitrogen atoms of said ligands, and Cl.sup. as counter anions, wherein said metal-organic material has the chemical formula (NiCl.sub.2N.sub.2C.sub.26.5H.sub.16).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified NiClL1 and may be formed, e.g., by adding a chloroform solution of L1 to a dimethylformamide (DMF) suspension of NiCl.sub.2.6H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain NiClL1 as a light green precipitate having the geometrical shape of an elongated hexagons (brick-like). The NiClL1 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(81) In another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L1, Ni(II) ions structurally coordinated with nitrogen atoms of said ligands, and Br.sup. as counter anions, wherein said metal-organic material has the chemical formula (NiBr.sub.2N.sub.2C.sub.26.5H.sub.16).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified NiBrL1 and may be formed, e.g., by adding a chloroform solution of L1 to a DMF suspension of NiBr.sub.2 in an oven-dried glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain NiBrL1 as a light green precipitate. The NiBrL1 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(82) In still another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Ni(II) ions structurally coordinated with nitrogen atoms of said ligands, and Cl.sup. as counter anions, wherein said metal-organic material has the chemical formula (NiCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified NiClL2 and may be formed, e.g., by carefully layering a chloroform solution of L2 below a DMF solution of NiCl.sub.2.6H.sub.2O in an oven-dried glass tube, which is then sealed and kept in the dark for 5 days, to thereby obtain NiClL2 as a light green precipitate. The NiClL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(83) In yet another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Ni(II) ions structurally coordinated with nitrogen atoms of said ligands, and Br.sup. as counter anions, wherein said metal-organic material has the chemical formula (NiBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified NiBrL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of NiBr.sub.2 in a glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain NiBrL2 as a light green precipitate having the geometrical shape of near-regular hexagons. The NiBrL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(84) In another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Cu(II) ions structurally coordinated with nitrogen atoms of said ligands, and Cl.sup. as counter anions, wherein said metal-organic material has the chemical formula (CuCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified CuCIL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of CuCl.sub.2 in a glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain CuCIL2 as a dark green precipitate. The CuCIL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(85) In still another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Cu(II) ions structurally coordinated with nitrogen atoms of said ligands, and Br.sup. as counter anions, wherein said metal-organic material has the chemical formula (CuBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified CuBrL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of CuBr.sub.2 in a glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain CuBrL2 as a dark green precipitate having the geometrical shape of stella-octangula. The CuBrL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(86) In yet another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Cu(II) ions structurally coordinated with nitrogen atoms of said ligands, and NO.sub.3 as counter anions, wherein said metal-organic material has the chemical formula (Cu(NO.sub.3).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified Cu(NO.sub.3).sub.2L2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of Cu(NO.sub.3).sub.2 in a glass pressure tube, which is then sealed; heated for 5 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain Cu(NO.sub.3).sub.2L2 as a dark green precipitate. Alternatively, Cu(NO.sub.3).sub.2L2 may be formed by adding a dry chloroform solution of L2 to a dry DMF solution of Cu(NO.sub.3).sub.2.3H.sub.2O under N.sub.2 atmosphere in an oven-dried glass pressure tube, which is then sealed; heated for 6 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain Cu(NO.sub.3).sub.2L2 as a light green precipitate having the geometrical shape of rectangular prisms. The Cu(NO.sub.3).sub.2L2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(87) In another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Cu(II) ions structurally coordinated with nitrogen atoms of said ligands, and OTf.sup. as counter anions, wherein said metal-organic material has the chemical formula (Cu(OTf).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified Cu(OTf).sub.2L2 and may be formed, e.g., by carefully layering a chloroform solution of L2 below a DMF solution of Cu(OTf).sub.2 in an oven-dried glass tube, which is then sealed and kept in the dark for 5 days, to thereby obtain Cu(OTf).sub.2L2 as a light blue precipitate. Alternatively, Cu(OTf).sub.2L2 may be formed by carefully layering a chloroform solution of L2 below a DMF solution of Cu(OTf).sub.2 in an oven-dried glass tube, which is then sealed and kept in the dark for 10 days; heated for another 2 days at 60 C. without stirring and with exclusion of light; and then gradually cooled to RT to thereby obtain Cu(OTf).sub.2L2 as a light blue precipitate. The Cu(OTf).sub.2L2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(88) In still another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Pd(II) ions structurally coordinated with nitrogen atoms of said ligands, and Cl.sup. as counter anions, wherein said metal-organic material has the chemical formula (PdCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified PdClL2 and may be formed, e.g., by adding a sonicated toluene solution of Pd(COD)Cl.sub.2 to a toluene suspension of L2 in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain PdClL2 as a yellowish precipitate. In one alternative process, PdClL2 may be formed by adding a sonicated toluene suspension of PdCl.sub.2 to a toluene suspension of L2 in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain PdClL2 as a yellowish precipitate. In another alternative process, PdClL2 may be formed by adding an ethylbenzene solution of Pd(PhCN).sub.2Cl.sub.2 to an ethylbenzene suspension of L2 in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain PdClL2 as a yellowish precipitate. In a further alternative process, PdClL2 may be formed by adding a toluene solution of Pd(PhCN).sub.2Cl.sub.2 to a heptane suspension of L2 in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain PdClL2 as a yellowish precipitate. The PdClL2 crystalline structures obtained may further comprise toluene, ethylbenzene and/or heptane molecules confined within the structural pores.
(89) In yet another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Zn(II) ions structurally coordinated with nitrogen atoms of said ligands, and OAc.sup. as counter anions, wherein said metal-organic material has the chemical formula (Zn(OAc).sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified ZnOAcL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of Zn(OAc).sub.2.2H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 2 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnOAcL2 as a light white precipitate having the geometrical shape of spheres. Alternatively, ZnOAcL2 may be formed by adding a chloroform solution of L2 to a DMF solution of Zn(OAc).sub.2.2H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnOAcL2 as a light white precipitate having the geometrical shape of spheres. The ZnOAcL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(90) In another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Zn(II) ions structurally coordinated with nitrogen atoms of said ligands, and Cl.sup. as counter anions, wherein said metal-organic material has the chemical formula (ZnCl.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified ZnClL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of ZnCl.sub.2.2H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnClL2 as a light white precipitate having the geometrical shape of spheres. In one alternative process, ZnClL2 may be formed by adding a chloroform solution of L2 to a DMF solution of ZnCl.sub.2.2H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 2 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnClL2 as a light white precipitate having the geometrical shape of spheres. In another alternative process, ZnClL2 may be formed by adding a chloroform solution of L2 to a DMF solution of ZnCl.sub.2.2H.sub.2O in an oven-dried glass pressure tube, which is then sealed; heated for 3 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnClL2 as a light white precipitate having the geometrical shape of spheres. The ZnClL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(91) In still another specific embodiment, the metal-organic material of the invention comprises ligands each being ligand L2, Zn(II) ions structurally coordinated with nitrogen atoms of said ligands, and Br.sup. as counter anions, wherein said metal-organic material has the chemical formula (ZnBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n wherein n is an integer of at least 4, and a 3D crystalline micro or sub-micro structure optionally further comprising solvent molecules. This material is herein identified ZnBrL2 and may be formed, e.g., by adding a chloroform solution of L2 to a DMF solution of ZnBr.sub.2 in an oven-dried glass pressure tube, which is then sealed; heated for 2 days at 105 C. without stirring and with exclusion of light; and then gradually cooled to RT over 9-10 h. to thereby obtain ZnBrL2 as a white precipitate having the geometrical shape of spheres. The ZnBrL2 crystalline structures obtained may further comprise chloroform and/or DMF molecules confined within the structural pores.
(92) In another aspect, the present invention relates to a method for the preparation of a metal-organic material as defined above, comprising the steps of: (i) providing (a) an organic solution or suspension of a metal salt, herein referred to as the metal component, consisting of anions and said metal ions; and (b) an organic solution or suspension of said ligands, herein referred to as the organic component, in a pressure vessel; (ii) sealing and keeping said pressure vessel for a period of time, e.g., for about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 days, or more, with exclusion of light and without stirring, thereby reacting said metal ions with said ligands to obtain said metal-organic material as a precipitate; and (iii) collecting said precipitate. It should be noted that where particular values are described in the description and claims, unless otherwise stated, the term about means that an acceptable error range, e.g., up to 5% or 10%, for the particular value should be assumed.
(93) The term pressure vessel as used herein refers to a closed container designed to hold liquids or gases at a pressure substantially different from the ambient pressure. Pressure vessels can theoretically be almost any shape, e.g., cylinders with end caps, i.e., heads, either hemispherical or dished (torispherical), and can be made of any suitable composite material. In one embodiment, the pressure vessel utilized in the method of the present invention is a glass pressure vessel, more particularly, a glass pressure tube as used in the studies described herein.
(94) In certain embodiments, step (ii) of the method of the invention is carried out while heating the pressure vessel containing the metal salt solution/suspension and the ligand solution/suspension to a temperature ranging from 60 C. to 120 C., e.g., from 60 C. to 70 C., 70 C. to 80 C., 80 C. to 90 C., 90 C. to 100 C., 100 C. to 105 C., 105 C. to 110 C., 110 C. to 115 C., or 115 C. to 120 C., for the whole said period of time or a part thereof, and then gradually cooling said pressure vessel. As shown herein, in some cases, step (ii) comprises sealing and keeping said pressure vessel for a period of time with exclusion of light and without stirring, while heating to a temperature as defined above for the whole period of time and then gradually cooling, e.g., to room temperature, prior to step (iii). Alternatively, step (ii) may comprise sealing and keeping said pressure vessel for a period of time with exclusion of light and without stirring, while heating as defined above for a part of said period of time, i.e., at the beginning of said period of time, during said period of time, or at the end of said period of time, and then gradually cooling, e.g., to room temperature.
(95) In certain embodiments, steps (i) and (ii) of the method of the invention are carried out under inert conditions, e.g., under argon or N.sub.2.
(96) The organic solvents in which said ligands and metal salt are dissolved may independently be either polar or non-polar, wherein the solubility of the ligands in the organic solvent in which they are dissolved determines whether the organic component would be in the form of a solution or suspension, and the solubility of the metal salt in the organic solvent in which it is dissolved determines whether the metal component would be in the form of a solution of suspension. Non-limiting examples of organic solvents include chloroform, dimethylformamide (DMF), alkanols such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, isobutanol, pentanol and hexanol, DMSO, acetonitrile, ethylene glycol, toluene, benzene, ethylbenzene, ether (diethyl ether), and alkanes such as pentane, hexane, cyclohexane, heptane, cycloheptane, octane, cyclooctane, nonane, decane and decalin.
(97) As shown herein, in cases the solubility of the metal salt in the organic solvent utilized is poor, however an organic solution rather than suspension of the metal salt is desired, a compound capable of forming a coordination complex, i.e., metal complex, with the metal atom thus increasing the solubility of said metal salt in said organic solvent may be added. In particular such cases exemplified herein, PdCl.sub.2 in which the Pd atoms are coordinated with 1,5-cyclooctadiene (COD) or benzonitrile (PhCN), i.e., Pd(COD)Cl.sub.2 or Pd(PhCN).sub.2Cl.sub.2, respectively, were dissolved in toluene or ethylbenzene so as to obtain a toluene or ethylbenzene solution rather than suspension of PdCl.sub.2.
(98) According to the method of the invention, the metal-organic material is obtained as a result of a reaction taking place in the pressure vessel during step (ii). As clearly shown herein, metal-organic materials comprising the same ligands and metal ions, but having different 3D crystalline structures, thus potentially different physical and chemical properties, are obtained depending on the reaction components, e.g., anions and organic solvents in which said ligands and metal salt are dissolved, as well as the reaction conditions, e.g., the period of time during which the organic component and metal component are reacted in step (ii), the temperature in which the reaction is conducted or the thermal profile of the reaction (in cases the reaction includes heating for a part of said period of time), and cooling rate (in cases the reaction comprises heating for the whole said period of time or a part thereof).
(99) The metal-organic material obtained by the method of the present invention comprises metal ions, preferably transition metal ions, coordinated to organic ligands each of the general formula I to form one-, two-, or three-dimensional structures, wherein the particular metal ion and organic ligand selected dictates the structure and hence physical and chemical properties of the material. In certain embodiments, the metal-organic material has a 3D crystalline micro or sub-micro structure that may have a particular geometric shape as defined above. It should be understood that while crystalline micro and sub-micro structures obtained using different reaction components and/or under different reaction conditions may have different geometrical shapes, a preparation process as defined above, utilizing particular reaction components and carried out under particular reaction conditions, results in a population of 3D crystal structures having uniform geometrical shape.
(100) In certain embodiments, the geometrical shape of the 3D micro and sub-micro structures obtained by the method of the invention is thus affected by reaction components and/or the reaction conditions or parameters in steps (ii), wherein said reaction components are, e.g., one or more of said metal ions, anions, and organic solvents, and said reaction conditions or parameters are, e.g., one or more of said temperature, period of time, and cooling rate.
(101) The MOFs of the present application are useful as adsorbents in processes for gas adsorption, e.g., H.sub.2, CO, CO.sub.2 or methane adsorption, or gas separation and/or purification, e.g., separation of CO.sub.2 from methane.
(102) In yet another aspect, the present invention thus relates to use of a metal-organic material as defined above as an adsorbent in a process for gas adsorption or gas separation.
(103) In still another aspect, the present invention relates to a process for gas adsorption or gas separation by adsorbing said gas to an adsorbent, the improvement wherein said adsorbent is a metal-organic material as defined above.
(104) The invention will now be illustrated by the following non-limiting Examples.
EXAMPLES
(105) Materials and Methods
(106) General Methods.
(107) Glass pressure tubes were cleaned by immersion in a piranha solution (7:3 v/v, H.sub.2SO.sub.4/30% H.sub.2O.sub.2) for 10 min and deionized (DI) water and then dried for 12 h at 130 C. Caution: piranha is an extremely dangerous oxidizing agent and should be handled with care using appropriate personal protection.
(108) Transmission Electron Microscopy (TEM).
(109) TEM imaging was performed with a Philips CM-120 instrument operating at 120 kV, equipped with a charge-coupled device camera (2k2k Gatan Ultrascan 1000). TEM samples were prepared by placing a 5 l drop of the reaction mixture on a formvar/carbon, 400 mesh Cu grid and blotting after 10 s. Due to beam sensitivity of the specimens, TEM imaging and SAED measurements were performed under low-dose conditions. An EDAX EDS system was used to perform the elemental analysis.
(110) Scanning Electron Microscopy (SEM).
(111) SEM measurements were performed using HRSEM ULTRA-55 ZEISS and HRSEM SUPRA-55 VP ZEISS instruments at an EHT voltage of 3 kV. SEM samples were prepared by placing a drop of the reaction mixture or a DMF suspension of isolated MOFs on a silicon substrate which was dried under air.
(112) FTIR and NMR Spectroscopy.
(113) The infra-red spectra were obtained using a Nicolet 460 single beam FT-IR. .sup.1H and .sup.13C{.sup.1H}NMR measurements were run on a 300 MHz Bruker NMR spectrometer.
(114) Atomic Force Microscope (AFM).
(115) AFM topographical imaging was performed on a P47 Solver AFM (NT-MDT, Zelenograd, Russia) using AC240 probes (Olympus) in intermittent contact mode, as well as with Multimode 8 AFM (Bruker, Santa Barbara, Calif.). The latter system was operated with the Peak force Quantitative Mechanical Mapping (PF-QNM) mode which enables acquisition of elastic modulus simultaneously with the topographic image. For this measurement, Bruker RTESPA probes were used. The spring constant, determined by the Sader method (Sader et al., 1999) was 80 N/m. The elastic modulus is derived from force curves acquired at each pixel, and rely on several calibrations (cantilever deflection sensitivity, spring constant, tip radius) which are input into the DMT analysis (Tabor, 1977). The deformation was on the order of 5-10 nm, thus very sensitive to the tip and sample surface condition, which can change the effective tip radius during course of scan. Estimated uncertainty in modulus measurement is 30%. Samples were prepared on silicon substrates as in the case of SEM.
(116) Rapid Thermal Processing (RTP) and Thermogravimetric Analysis (TGA).
(117) RTP was carried out on a Rapid Thermal Annealer for 5 min. under a stream of 10% H.sub.2/N.sub.2 or under vacuum at different temperatures (200-600 C.). The samples were prepared as in the case of SEM. TGA was performed on a SDT Q600 V8.3 Build 101 instrument using alumina sample pans under a stream of N.sub.2.
(118) Magnetic Measurements.
(119) The magnetic properties of isolated samples were measured using a SQUID magnetometer MPMS XL. The samples were weighed and placed in gelatine capsules and cooled from RT down to 2K without applying any external magnetic field (ZFC) and an internal magnetic field of strength 1000 Oe (FC). Temperature dependences of the magnetic moment were measured during heating from 2K to 300K under an applied external magnetic field (H=1000 Oe). The dependence of magnetic susceptibility on the temperature was normalized using the estimated chemical formula of NiClL1 (NiCl.sub.2N.sub.2C.sub.26.5H.sub.16).sub.n and NiBrL2 (NiBr.sub.2N.sub.2C.sub.26.5H.sub.20).sub.n. This dependence is similar for the inclusion of DMF (0.5-4 molecules/Ni). The ZFC and FC dependences were found to be superimposed (
(120) Gas Uptake Studies.
(121) The gas adsorption studies were carried out on a Pressure Composition Isotherm (PCI) instrument (Advanced Materials Corporation, USA). About 50 mg of the compound, e.g., NiClL1, was loaded into a sample chamber inside a glove box under argon. The sample chamber was then connected to a vacuum line. The sample was activated by heating slowly to 120 C. (for CH.sub.4 adsorption) and to 70 C., 100 C. and 120 C. (for H.sub.2 adsorption) and held for 4 hours at these temperatures followed by cooling to RT. The temperature of the sample chamber was held constant during the measurements. The gas uptake was determined using Sieverts principle. The density of the sample was measured by gas pycnometry using helium (10 bar).
(122) General Procedure for the Synthesis of the MOFs.
(123) A CHCl.sub.3 solution (1.0 ml) of the polypyridyl ligand L1 (Schilling et al., 2011) or L2 (Thompson et al., 1997) (6.8 mol) was added to a DMF solution (3.0 ml) of the corresponding metal salt: NiCl.sub.2, NiBr.sub.2, CuCl.sub.2, CuBr.sub.2 and Cu(NO.sub.3).sub.2 (6.8 mol for 1 eq. and 13.6 mol for 2 eq.), in a glass pressure tube. Then, the tube was sealed and heated for 5 days at 105 C. without stirring and with exclusion of light, followed by controlled cooling to RT over 9-10 h in steps of 10 C./h. This resulted in a precipitate (light green for the Ni-based MOFs and dark green for the Cu-based MOFs). The MOFs were collected in near quantitative yield (>95%) by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor.
(124) Study 1. Homogeneously Microstructured Srystalline Nickel-Organic Coordination Polymers
(125) Micro-sized brick-like structures of the coordination polymer were obtained by differential solvothermal synthesis as described. A DMF solution of 1 equivalent of NiCl.sub.2.6H.sub.2O was heated with a chloroform solution of 0.5 equivalents of the ligand L1 in a sealed pressure tube at 105 C. for 5 days in the dark, and then subjected to slow cooling over 9-10 hours. A white precipitate was formed immediately on mixing the two solutions and was allowed to stand and sediment without disturbance under the mentioned conditions. After cooling to RT, the light green precipitate was collected by centrifugation.
(126) SEM image of NiClL1 revealed the brick-like structures and a statistical analysis on three hundred randomly chosen brick-like structures from a representative sample of NiClL1 established a reasonable uniformity in size distribution (
(127) AFM studies revealed the same shapes as seen in electron micrographs as well as the apparent surface roughness of the material. The debris observed also in the TEM micrographs appears to be disordered material, ranging from tens to over one hundred nm height. The upper surface of the crystallites was generally flat, although scattered depressions could be observed, as well as new layers appearing over parts of the surface (
(128) Measurements of elastic modulus on these nanostructures gave values between 2-12 gigapascals (GPa). These values are within the range of those observed for organic crystals (Roberts et al., 1991). The elastic modulus was measured simultaneously with the topographic image, so values are correlated at the pixel level with topographic features.
(129) FT-IR spectrum (KBr pellets) of NiClL1 showed a shift of 20 cm.sup.1 compared to free ligand L1 (
(130) The formation of these well-defined rectangular structures may be viewed as an impact of face or axial confined growth mechanism, but the mechanistic understanding behind the formation of such uniform structures is still preliminary and can be expected to follow a regular coordination process followed by a thermally initiated close packing by the fusion of individual building blocks. Time dependent SEM analysis alongside the course of reaction revealed a speculative but justifiable mechanism for the formation of the finally observed structures. As expected, the ligand L1 on mixing with the Ni salt solution immediately formed the corresponding coordination polymer with non-uniform rod- and very small block-like structures (
(131) The micro moieties thus obtained was found to be insoluble in all common solvents including water and was found to be stable in most of the commonly used solvents in air at RT. This stability of the structure may be established by the SEM images of the solid material suspended in water, DMF and a mixture of both in dark, taken after 2 months (
(132) The final structure of the coordination polymer was found to depend on several parameters including the technique employed, molar ratios of the reagents, solvent system, time of the reaction and temperature. It has already been mentioned that mixing a CHCl.sub.3 solution of the ligand L1 with a DMF solution of NiCl.sub.2.6H.sub.2O at RT gave non-uniform rod- and very small block-like structures. Layering carefully a CHCl.sub.3 solution of the ligand L1 under a DMF solution of the Ni salt in a molar ratio of 1:1 or 1:2 afforded a light green precipitate when allowed to stand overnight in the dark, and SEM images of a representative sample showed a mixture of rodslonger and more uniform and some amounts of junk material with no well-defined structure. Heating this mixture (after complete diffusion in about 4 days) in a pressure tube to 80-105 C. for 3-5 days brought about drastic changes in the structures observed under SEM suggesting that the longer rods thus obtained were unstable and underwent random melting and fusion under thermal treatment as the junk material along with the rods seemed to have aggregated to form some sort of lumps.
(133) Although changing the molar ratio of the ligand and the metal did not affect much the outcome of the layering technique, it was found to have substantial effect on the structural features under thermal protocol. Heating the ligand and the metal in the same solvent system under the same conditions, but in a ratio of 1:1, resulted in smaller and different brick-like structures with a wider size distribution (
(134) The solvents used for the reaction were also found to have pronounced effect on the final structures observed under the electron microscopes. Using DMF alone as the solvent even though the ligand L1 was insoluble (
(135) The thermal behavior of materials is yet another interesting aspect of coordination polymers. RTP under a stream of 10% H.sub.2/N.sub.2 of the brick-like Ni(II) coordination polymer established that the structure are stable upto a temperature around 300 C. (
(136) Another significant observation was that the structures appear to be much more stable if thermally treated under vacuum (
(137) The TGA on the brick-like structures allowed us to confirm the presence of DMF as a coordinating solvent inside the crystal lattice, since a weight loss was observed around 150 C. (
(138) Metal organic frameworks and coordination polymers find interesting application as gas storage materials (Manson et al., 2014; Adisa et al., 2012). The gas adsorption properties NiClL1 was studied as a function of pressure and the experiments done on pre-activated samples showed reasonable amount of methane (about 7.5 wt % at ambient temperature or 0 C. and 11.7 wt % at 78.5 C. and 35 atm pressure) and hydrogen (about 1.75 wt % at 35 atm pressure) adsorption (
(139) SQUID measurements revealed paramagnetic behavior for both NiClL1 and NiBrL2. The ZFC and FC dependences were found to be superimposed (
(140) It has been tried via various techniques including electron diffraction, powder XRD and synchrotron diffraction, to solve the crystal structure of NiClL1, but has remained unsuccessful till date, partially due to the size of the crystallite (that made it difficult to isolate a single crystal and to have a compatible beam line in the range of the size of the crysallite) and partially due to the low intensity of diffraction patterns observed (especially in electron diffraction). Nevertheless, the magnetic properties throw some light into the possible geometrythe paramagnetic behavior neglects to a large extent the possibility of a square planar Ni(II) complex, thereby leaving the options for a tetrahedral or an octahedral one. It has already been known that in a square planar complex, the ligand exerts a very strong interaction with the metal at the expense of complete electron pairing, leaving the * orbitals unoccupied, resulting in a diamagnetic behavior (Bridgeman, 2008).
(141) Study 2. Topological Control in Metal Organic Frameworksfrom Rectangular Bricks to Stellated and Interpenetrating Polyhedra
(142) In this study, we demonstrate the control of structural uniformity and diversity for MOFs. More particularly, we introduce the assembly of a series of 3-dimensional (sub)-microstructured MOFs with a narrow size distribution as well as excellent control over their topologies. Diverse structures are demonstrated, ranging from elongated hexagons and rectangular prisms to stellated and interpenetrating polyhedral, by systematically varying the (i) metal center; (ii) anion; (iii) organic ligand; and (iv) reaction conditions, i.e., solvent, temperature, and aerobic vs. anaerobic. For instance, the use of Ni(II) salts result in distinct polyhedral topologies as opposed to Cu(II) precursors that form interpenetrating and/or stellated polyhedra. Such metal-organic structures are highly uncommon (Masoomi and Morsali, 2013). The uniformity in shape and size of our materials is attained via solvothermal synthesis without the use of surfactants or external modulators (e.g., pyridine, cetyl trimethyl ammonium bromide) (Sindoro et al., 2014; Gao et al., 2014; Ranft et al., 2013; Guo et al., 2012; Cho et al., 2008). Follow-up electron microscopy studies of the formation of the MOFs revealed a complex sequence of reactions. For the Ni-based MOFs, two types of growth process were observed involving nucleation and polishing, whereas fusion processes play a dominant role in the formation of the Cu-based MOFs.
(143) To achieve and rationalize the topological control over metal-organic microstructures, ligand-metal-anion combinations are needed that: (i) form robust and extended 3D networks by interconnected tetrahedral nodes allowing the generation of diamondoid networks (Batten, 2001); and (ii) give rise to exceptionally high permanent microporosities and/or channels with incorporation of solvent molecules to stabilize the microstructures. Therefore, we used the two organic ligands L1 and L2 and commercially available salts of Ni(II) and Cu(II). These tetrahedral ligands are rigid, possess a full T.sub.d symmetry, and four metal ion binding sites. This combination ensures the formation of robust, porous and extended 3D networks (Lu et al., Chem. Soc. Rev., DOI: 10.1039/C4CS00003J). Ni(II) and Cu(II) salts have a high affinity for pyridyl ligands (Tomasik et al., 2008; Hasenknopf et al., 1996), nevertheless the metal-N bond strength allows for the rearrangement of kinetic structures into thermodynamic products to occur at elevated temperatures (Kaminker et al., 2011). The scope of this study is demonstrated by the use of metals that have different coordination requirements. In addition, the dominant role of the anions in the formation of our microstructures has been demonstrated.
(144) In a typical experiment, a DMF solution of the metal salt was mixed with a chloroform solution of 0.5 or 1 equivalent of L1 or L2 and heated in a glass pressure tube at 105 C. with the exclusion of light. After 4-5 days, the reaction mixture was gradually cooled over 9-10 hours and the microstructures were collected quantitatively by centrifugation. The crystalline microstructures have been characterized by electron microscope analysis, XRD and AFM. Information at the molecular level has been obtained by infra-red (IR) spectroscopy, magnetic measurements, and gas adsorption. The nickel structures have also been tested for their thermal stability.
(145) SEM and TEM imaging revealed that the combinations of NiCl.sub.2 and L1 or NiBr.sub.2 and L2 in a 2:1 ratio, respectively, yield monodispersed structures (NiClL1 and NiBrL2;
(146) AFM measurements of NiClL1 and NiBrL2 confirmed the topologies and allowed precise measurement of the structure height (
(147) The isolated NiClL1 and NiBrL2 are air stable at RT in the dark for at least one year. Immersing these MOFs in DMF or water for several months does not induce any observable change in their microstructure. TGA of NiClL1 showed a relatively small weight decrease of 3.4% around 86 C. corresponding with the loss of CHCl.sub.3 (
(148) The porosity of NiClL1 was demonstrated by gas adsorption analysis. NiClL1 was activated at 120 C. under high vacuum for several hours to evaluate its adsorption/release efficiency for natural gas (CH.sub.4). The CH.sub.4 adsorption is 7.5 wt % at 0-20 C., and 11.7 wt % at 78.5 C. under a pressure of 35 atm. The hysteresis between adsorption and desorption runs is negligible, confirming the microporosity and the reversibility of the CH.sub.4 uptake (
(149) The use of Cu salts resulted in MOFs with strikingly differently structures. Non-uniform structured MOFs were obtained with CuCl.sub.2 and L2 (
(150) The nature of the anions and the metal-to-ligand ratio are also key parameters for the formation of well-defined Cu-based MOFs. The use of Cu(NO.sub.3).sub.2 and a 1:2 (metal:L2) ratio resulted in ill-defined structures, contrasted with the higher degree of uniformity obtained for a 1:1 ratio. The latter resulted in flower-like topologies (Cu(NO.sub.3)L2;
(151) The formation of the MOFs is probably a result of a complex cascade of assembly processes (Spokoyny et al., 2009; Oh and Mirkin, 2005). For both Ni and Cu-based MOFs the solvent composition plays a crucial role as well for the generation of uniform structures (
(152) Extending the electron microscope studies of the formation of the Ni- and Cu-based MOFs revealed interesting mechanistic information. A time-dependent analysis showed distinctly different pathways for the formation of the uniform structures obtained. Mixing the solutions of NiCl.sub.2 and NiBr.sub.2 salts with the corresponding ligand (L1 or L2) result in an immediate precipitation. Apparently, the process starts with the coordination of the ligand to the metal center as the first nucleation step as common in crystallizations and colloid synthesis. SEM analysis of NiClL1 aliquots taken immediately upon mixing showed the formation of a mixture of elongated (needles) and cubical structures (<1 m;
(153) The time-dependent SEM analysis of the growth of the Cu-based MOFs revealed a rather complicated sequence involving several intermediate structures. Mixing a solution of CuBr.sub.2 with L2 resulted at RT in non-uniform plate-like structures (
(154) The formation of Cu(NO.sub.3)L2 starts with the formation non-uniform plate-like structures similar to the ones observed for CuBrL2 (
(155) Our observations show that the formation of metal-organic microcrystals with a uniform size distribution can be readily achieved by solvothermal synthesis. Others have been using solvothermal approaches for attaining structural modifications mainly at the molecular level (Stock and Biswas, 2011). In addition, crystal packing variation through systematic chemical modifications is known for many organic and other materials (Stock and Biswas, 2011; Zhao et al., 2011; Smulders et al., 2013; Wang et al., 2013; Shirman et al., 2008). However, such an approach to obtain uniform microcrystals is rare (Masoomi and Morsali, 2013; Ban et al., 2013). It is remarkable that varying the intramolecular structure (i.e., CC vs. CC, Cl vs. Br, Ni vs. Cu) has such a striking effect on the formation, uniformity and topology of the here reported MOFs. Our approach to obtain uniformity at the (sub)-micron level is sensitive to the position of the metal in the perodic table, as well as the reaction time. For example, we have shown previously that the reaction of Pd(II) salts with L2 resulted in the formation of coordination-polymer nanotubes (Kaminker et al., 2011). Structural features and dimensions of such nanotubes are assembly dependent as shown by Aida et al. (Zhang et al., 2009). In the present study, mixtures of (sub)-microstructures were observed initially which gradually transformed into the homogeneously structured crystals. Although this work has not attempted to characterize the factors which predetermine the topology of such microstructures, the possibility of custom-designed topologies is enticing. Considering the range of parameters considered in this study, the possibility for shape-specificity and size uniformity in MOFs could be expected to be a wide and general phenomenon.
(156) Study 3. Various Metal Organic Frameworks
(157) In a series of experiments described herein below, various MOFs have been prepared using the general procedure described above, wherein different metal salts and reaction conditions are utilized.
(158) A CHCl.sub.3 solution (1.0 ml) of L1 (5 mg, 6.9 mol) was added to a DMF suspension (3.0 ml) of NiBr.sub.2 (3 mg, 13.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 5 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light green precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(159) A CHCl.sub.3 solution (2.0 ml) of L1 (5 mg, 6.9 mol) was added to a DMF suspension (3.0 ml) of NiCl.sub.2.6H.sub.2O (3.3 mg, 13.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 5 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light green precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(160) A CHCl.sub.3 solution (1.0 ml) of L2 (5.7 mg, 7.8 mol) was carefully layered below a DMF solution (3.0 ml) of NiCl.sub.2.6H.sub.2O (1.9 mg, 7.8 mol) in an oven-dried glass tube, which was sealed and kept in the dark for 5 d, resulting in a light green precipitate and was collected by centrifugation for 10 min. at 5000 rpm and decanting the mother liquor (
(161) A sonicated toluene solution (2.0 ml) of Pd(COD)Cl.sub.2 (4.5 mg, 15.6 mol) was added to a toluene suspension (4.0 ml) of L2 (5.7 mg, 7.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a yellowish precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(162) A sonicated toluene suspension (2.0 ml) of PdCl.sub.2 (2.8 mg, 15.6 mol) was added to a toluene suspension (4.0 ml) of L2 (5.7 mg, 7.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a yellowish precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(163) An ethylbenzene solution (2.0 ml) of Pd(PhCN).sub.2Cl.sub.2 (5 mg, 15.6 mol) was added to an ethylbenzene suspension (4.0 ml) of L2 (5.7 mg, 7.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a yellowish precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(164) A toluene solution (3.0 ml) of Pd(PhCN).sub.2Cl.sub.2 (5 mg, 15.6 mol) was added to a heptane suspension (3.0 ml) of L2 (5.7 mg, 7.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a yellowish precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(165) A CHCl.sub.3 solution (1.0 ml) of L2 (5.7 mg, 7.8 mol) was carefully layered below a DMF solution (3.0 ml) of Cu(OTf).sub.2 (2.8 mg, 7.8 mol) in an oven-dried glass tube, which was sealed and kept in the dark for 5 d, resulting in a light blue precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(166) A CHCl.sub.3 solution (1.0 ml) of L2 (5.7 mg, 7.8 mol) was carefully layered below a DMF solution (3.0 ml) of Cu(OTf).sub.2 (2.8 mg, 7.8 mol) in an oven-dried glass tube, which was sealed and kept in the dark for 10 days and then heated for another 2 days at 60 C. without stirring and with exclusion of light, followed by subsequent cooling to RT temperature, resulting in a light blue precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(167) A dry CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a dry DMF solution (3.0 ml) of Cu(NO.sub.3).sub.2.3H.sub.2O (1.65 mg, 6.8 mol) in an oven-dried glass pressure tube under N.sub.2 atmosphere, which was sealed and heated for 6 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light green precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(168) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of Zn(OAc).sub.2.2H.sub.2O (3 mg, 13.6 mol) in an oven-dried glass pressure tube, which was sealed and heated for 2 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(169) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of Zn(OAc).sub.2.2H.sub.2O (3 mg, 13.6 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(170) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of ZnCl.sub.2.2H.sub.2O (0.92 mg, 6.8 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(171) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of ZnCl.sub.2.2H.sub.2O (1.86 mg, 13.6 mol) in an oven-dried glass pressure tube, which was sealed and heated for 2 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(172) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of ZnCl.sub.2.2H.sub.2O (1.86 mg, 13.6 mol) in an oven-dried glass pressure tube, which was sealed and heated for 3 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a light white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
(173) A CHCl.sub.3 solution (1.0 ml) of L2 (5 mg, 6.8 mol) was added to a DMF solution (3.0 ml) of ZnBr.sub.2 (3.1 mg, 13.6 mol) in an oven-dried glass pressure tube, which was sealed and heated for 2 days at 105 C. without stirring and with exclusion of light, followed by subsequent controlled cooling to RT over 9-10 h. at a rate of 10 C./h, resulting in a white precipitate and was collected by centrifugation of the reaction mixture for 10 min. at 5000 rpm and decanting the mother liquor (
APPENDIX
(174) ##STR00004## ##STR00005##
REFERENCES
(175) Adisa, O. O., Cox, B. J., Hill, J. M., Nanoscale, 2012, 4, 3295-3307 Bailar, J. C., Jr Prep. Inorg. React., 1964, 1, 1-57 Ban, Y., Li, Y., Liu, X., Peng, Y., Yang, W., Microporous and Mesoporous Materials, 2013, 173, 29-36 Batten, S. R., CrystEnggComm, 2001, 18, 1-7 Biradha, K., Ramanan, A., Vittal, J. J., Crystal Growth and Design, 2009, 9, 2969-2970 Bridgeman, A. J., Dalton Trans. 2008, 1989-1992 Carn-Snchez, A., Imaz, I., Stylianou, K. C., Maspoch, D., Chem. Eur. J., 2014, 20, 5192-5201 Chen, B., Xiang, S., Qian, G., Acc. Chem. Res., 2010, 43, 1115-1124 Cho, W., Lee, H. J; Oh, M., J. Am. Chem. Soc., 2008, 130, 16943-16946 Choudhury, L., Kaminker, R., Motiei, L., de Ruiter, G., Morozov, M., Lupo, F., Gulino, A., van der Boom, M. E., J. Am. Chem. Soc., 2010, 132, 9295 Cook, T. R., Yang, R. Y., Stang, P. J., Chem. Rev., 2013, 113, 734-777 Evans, O. R., Lin, W., Acc. Chem. Res., 2002, 35, 511 Furukawa, H., Cordova, K. E., O'Keeffe, M., Yaghi, O. M., Science, 2013, 341, 1230444 Gao, J., Ye, K., Yang, L., Xiong, W. W., Ye, L., Wang, Y., Zhang, Q., Inorg. Chem., 2014, 53, 691-693 Gu, X. W., Loynachan, C. N., Wu, Z., Zhang, Y. W., Srolovitz, D. J., Greer, J. R., Nano Lett., 2012, 12, 6385-6392 Guo, Y. N., Li, Y., Zhi, B., Zhang, D., Liua, Y., Huo, Q., RSC Adv., 2012, 2, 5424-5429 Hasenknopf, B., Lehn, J. M., Baum, G., Fenske, D., Proc. Natl. Acad. Sci. USA, 1996, 93, 1397-1400 Jeon, Y. M., Armatas, G. S., Kim, D., Kanatzidis, M. G., Mirkin, C. A., Small, 2009, 5, 46-50 Jung, S., Oh, M., Angew. Chem., Int. Ed. 2008, 47, 2049-2051 Kaminker, R., Motiei, L., Gulino, A., Fragal, I., Shimon, L. J. W., Evmenenko, G., Dutta, P., Iron, M. A., van der Boom, M. E., J. Am. Chem. Soc., 2010, 132, 14554 Kaminker, R., Popovitz-Biro, R., van der Boom, M. E., Angew. Chem, Int. Ed., 2011, 50, 3224-3226 Kitagawa, S., Kitaura, R., Noro, S., Angew. Chem., Int. Ed. 2004, 43, 2334 Kittel, C., Introduction to Solid State Physics. John Wiley and Sons, 1996 Kondo, M., Okubo, T., Asami, A., Noro, S.-i., Yoshitomi, T., Kitagawa, S., Ishii, T., Matsuzaka, H., Seki, K., Angew. Chem. Int. Ed. 1999, 38, 140-143 Lei, B. F., Li, B., Zhang, H. R., Zhang, L. M., Li, W. L., J. Phys. Chem. C, 2007, 111, 11291 Li, W., Doblinger, M., Vaneski, A., Rogach, A. L., Jackel, F., Feldmann, J., J. Mat. Chem., 2011, 21, 17946-17952 Liu, K., You, H., Jia, G., Zheng, Y., Huang, Y., Song, Y., Yang, M., Zhang, L., Zhang, H., Crystal Growth and Design, 2010, 10, 790-797 Long, J. R., Yaghi, O. M., Chem. Soc. Rev., 2009, 38, 1213-1214 Lu, Y., Cao, H., Zhang, S., Zhang, X., J. Mater. Chem., 2011, 21, 8633-8639 Lu, W., Wei, Z., Gu, Z. Y., Liu, T. F., Park, J., Park, J., Tian, J., Zhang, M., Zhang, Q., Gentle III, T., Bosch, M., Zhou, H. C., Chem. Soc. Rev., DOI: 10.1039/C4CS00003J (Advance Article) Manson, J. A., Veenstra, M., Long, J. R., Chem. Sci., 2014, 5, 32-51 Masoomi, M. Y., Morsali, A., RSC Adv., 2013, 3, 19191-19218 Murray, C. B., Sun, S., Daschler, W., Doyle, H., Betley, T. A., Kagen, C. R., Ibm. J. Res. & Dev., 2001, 45, 47-56 Ni, Z., Masel, R. I., J. Am. Chem. Soc., 2006, 128, 12394-12395 Noorduin, W., Grinthal, A., Mahadevan, L., Aizenberg, J., Science, 2013, 340, 832-837 Oh, M., Mirkin, C. A., Nature, 2005, 438, 651-654 Oh, M., Mirkin, C. A., Angew. Chem., Int. Ed. 2006, 45, 5492-5494 Park, K. H., Jang, K., Son, S. U., Sweigart, D. A., J. Am. Chem. Soc., 2006, 128, 8740-8741 Pevzner, A., Engel, Y., Elnathan, R., Tsukernik, A., Barkay, Z., Patolsky, F., Nano Lett., 2012, 12, 7-12 Ranft, A., Betzler, S. B., Haase, F., Lotsch, B. V., CrystEngComm, 2013, 15, 9296-9300 Rieter, W. J., Taylor, K. M. L., An, H., Lin, W., Lin, W., J. Am. Chem. Soc., 2006, 128, 9024-9025 Roberts, R. J., Rowe, R. C., York, P., Powder Technology, 1991, 65 139-146 Rowsell, J. L C., Yaghi, O. M., Angew. Chem., Int. Ed. 2005, 44, 4670 Sader, J. E., Chon, J. W. M., Mulvaney, P., Rev. Sci. Instrum., 1999, 70, 3967 Schilling, C. I., Plietzsch, O., Nieger, M., Muller, T., Brase, S., Eur. J. Org. Chem., 2011, 1743-1754 Seo, J. S., Whang, D., Lee, H., Jun, S. I., Oh, J., Jeon, Y. J., Kim, K., Nature, 2000, 404, 982 Shi, N., Xie, L., Sun, H., Duan, J., Yin, G., Xub, Z., Huang, W., Chem. Commun., 2011, 47, 5055-5057 Shirman, T., Lambre, J. F., Shimon, L. J. W., Gupta, T., Martin, J. M. L., van der Boom, M. E., Cryst. Growth Des., 2008, 8, 3066-3072 Sindoro, M., Yanai, N., Jee, A. Y., Granick, S., Acc. Chem. Res., 2014, 47, 459-469 Smulders, M. M., Riddell, I. A., Browne, C., Nitschke, J. R., Chem. Soc. Rev., 2013, 42, 1728-1754 Spokoyny, A. M., Kim, D., Sumrein, A., Mirkin, C. A., Chem. Soc. Rev., 2009, 38, 1218-1227 Stock, N., Biswas, S., Chem. Rev., 2011, 112, 933-969 Sun, X., Dong, S., Wang, E., J. Am. Chem. Soc., 2005, 127, 13102-13103 Tabellion, F. M., Seidel, S. R., Arif, A M., Stang, P. J., J. Am. Chem. Soc., 2001, 123, 7740 Tabor, D., J. Coll. Int. Sci. 1977, 58, 2-13 Tao, A. R., Habas, S., Yang, P., Small, 2008, 4, 310-325 Thompson, A. M. W. C., Hock, J, McCleverty, J. A., Ward, M. D., Inorg. Chim. Acta., 1997, 256, 331-334 Tomasik, P., Ratajewicz, Z., Newkome, G. R., Strekowski, L. E., In Chemistry of Heterocyclic Compounds: Pyridine Metal Complexes (Part 6, Volume 14). (John Wiley & Sons, Inc., 2008). Tuxen, A., Carenco, S., Chintapalli, M., Chuang, C. H., Escudero, C., Pach, E., Jiang, P., Borondics, F., Beberwyck, B., Alivisatos, A. P., Thornton, G., Pong, W. F., Guo, J., Perez, R., Besenbacher, F., Salmeron, M., J. Am. Chem. Soc., 2013, 135, 2273-2278 Wang, H., Zeng, Y., Ma, J. S., Fu, H., Yao, J., Mikhaleva, A. I., Trofimov, B. A., Chem. Commun., 2009, 5457-5459 Wang, C., Liu, D., Lin, W., J. Am. Chem. Soc., 2013, 135, 13222-13234 Wei, H., Li, B., Du, Y., Dong, S., Wang, E., Chem. Mater., 2007, 19, 2987-2993 Whitesides, G. M., Grzybowski, B., Science, 2002, 295, 2418-2421 Yaghi, O. M., Obkeeffe, M., Ockwig, N. W., Chae, H. K., Eddaoudi, M., Kim, J., Nature, 2003, 423, 705 Zhang, W., Jin, W., Fukushima, T., Ishii, N., Aida, T., Angew. Chem, Int. Ed., 2009, 48, 4747-4750 Zhao, X., Xiao, B., Fletcher, A. J., Thomas, K. M., Bradshaw, D., Rosseinsky, M. J., Science, 2004, 306, 1012 Zhao, X. Y., Liang, D. D., Liu, S. X., Sun, C. Y., Cao, R. G., Gao, C. Y., Ren, Y. H., Su, Z. M., Inorg. Chem., 2008, 47, 7133 Zhao, D., Timmons, D. J., Yuan, D., Zhou, H. C., Acc. Chem. Res., 2011, 44, 123-133