Phosphino-Quinoline-Pyridine Ligands and Methods

Abstract

Phosphino-quinoline-pyridine ligands and compositions that include complexes, the complexes including a phosphino-quinoline-pyridine ligand and a metal coordinated to the ligand are disclosed. Methods of oligomerization, such as methods of oligomerizing alpha-olefins, performed in the presence of a complex that includes a phosphino-quinoline-pyridine ligand are also disclosed.

Claims

1. A composition comprising a complex, wherein in the complex comprises: (i) a ligand of formula (I): ##STR00017## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), sulfonic acid (SO.sub.3H), or a halogen; wherein (a) R.sup.2, (b) R.sup.3, (c) R.sup.4, (d) R.sup.2 and R.sup.3, (e) R.sup.2 and R.sup.4, (f) R.sup.3 and R.sup.4, or (g) R.sup.2, R.sup.3, and R.sup.4 is not hydrogen; and (ii) a metal atom coordinated to the ligand.

2. The composition of claim 1 wherein: (A) the metal atom is not iron, and/or (B) (i) R.sup.2, (ii) R.sup.3, (iii) R.sup.4, (iv) R.sup.2 and R.sup.3, (v) R.sup.2 and R.sup.4, (vi) R.sup.3 and R.sup.4, or (vii) R.sup.2, R3, and R.sup.4, independently are selected from nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), or sulfonic acid (SO.sub.3H).

3. The composition of claim 1, wherein the two R.sup.1 substituents are identical.

4. The composition of claim 1, wherein each substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, independently, is selected from methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, phenyl, 3,5-dimethylphenyl, or cyclohexanone.

5. The composition of claim 1, wherein each halogen, independently, is selected from fluoro-, chloro-, or bromo-.

6. The composition of claim 1, wherein each R.sup.1, independently, is selected from phenyl, tert-butyl, iso-propyl, cyclohexyl, 3,5-dimethylphenyl, or iso-butyl.

7. The composition of claim 1, wherein R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, methyl, ethyl, iso-propyl, cyclohexyl, phenyl, nitro, sulfonate, sulfonic acid, fluoro-, chloro-, or bromo-.

8. The composition of claim 1, wherein each R.sup.1 is phenyl.

9. The composition of claim 1, wherein R.sup.2 is methyl or hydrogen.

10. The composition of claim 1, wherein R.sup.3 is hydrogen, and R.sup.4 is hydrogen.

11. The composition of claim 1, wherein the ligand has the following structure: ##STR00018##

12. The composition of claim 1, wherein the complex is of formula (II): ##STR00019## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), sulfonic acid (SO.sub.3H), or a halogen; wherein M is the metal atom; wherein X is a halogen; and wherein (a) R.sup.2, (b) R.sup.3, (c) R.sup.4, (d) R.sup.2 and R.sup.3, (e) R.sup.2 and R.sup.4, (f) R.sup.3 and R.sup.4, or (g) R.sup.2, R.sup.3, and R.sup.4 is not hydrogen.

13. The composition of claim 12, wherein: (A) the metal atom is not iron, and/or (B) (i) R.sup.2, (ii) R.sup.3, (iii) R.sup.4, (iv) R.sup.2 and R.sup.3, (v) R.sup.2 and R.sup.4, (vi) R.sup.3 and R.sup.4, or (vii) R.sup.2, R3, and R.sup.4, independently is selected from nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), or sulfonic acid (SO.sub.3H).

14. The composition of claim 1, wherein the metal atom comprises iron, cobalt, chromium, nickel, or a combination thereof.

15. The composition of claim 1, wherein the composition further comprises a co-catalyst.

16. The composition of claim 15, wherein the co-catalyst comprises an alkyl aluminum.

17. The composition of claim 16, wherein the aluminum of the co-catalyst is present in the composition at a mole ratio of aluminum to the ligand of about 750:1 to about 50:1.

18. The composition of claim 16, wherein the co-catalyst comprises tri-isobutyl aluminum (TIBA), triethylaluminum (TEA), trimethyl aluminum (TMA), methylaluminoxane (MAO), isobutyl-modified methylaluminoxane (MMAO), isobutyl-modified methylaluminoxane (TBA), or a combination thereof.

19. A method of oligomerization, the method comprising: (i) providing the composition of claim 1, (ii) providing a co-catalyst, (iii) providing an olefin, and (iv) contacting the olefin, the composition, and the co-catalyst for a time and at a temperature and a pressure effective to oligomerize at least a portion of the olefin to form an oligomerized product.

20. The method of claim 19, wherein (i) the temperature is about 20 C. to about 150 C., (ii) the pressure is about 10 psig to about 1,000 psig, (iii) the time is about 1 minute to about 60 minutes, or (iv) a combination thereof.

Description

DETAILED DESCRIPTION

[0031] The present disclosure is directed to ligands, compositions, and methods of performing chemical reactions, such as oligomerizations.

Ligands

[0032] In some embodiments, the ligands disclosed herein are phosphino-quinoline-pyridine (PQP) ligands. The ligands may include those of formula (I):

##STR00003##

[0033] wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), sulfonic acid (SO.sub.3H), or a halogen.

[0034] One or more of R.sup.2, R.sup.3, and R.sup.4 of formula (I) may not be hydrogen. For example, if R.sup.2 is not hydrogen, then R.sup.2 can be selected from a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), sulfonic acid (SO.sub.3H), or a halogen. In some embodiments, R.sup.2 is not hydrogen. In some embodiments, R.sup.3 is not hydrogen. In some embodiments, R.sup.4 is not hydrogen. In some embodiments, R.sup.2 and R.sup.3 are not hydrogen. In some embodiments, R.sup.2 and R.sup.4 are not hydrogen. In some embodiments, R.sup.3 and R.sup.4 are not hydrogen. In some embodiments, R.sup.2, R.sup.3, and R.sup.4, are not hydrogen.

[0035] In formula (I), the two R.sup.1 substituents can be the same or different. In some embodiments, the two R.sup.1 substituents are identical. In some embodiments, the two R.sup.1 substituents are different. Each R.sup.1, independently, can be selected from a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl.

[0036] The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be a substituted or unsubstituted alkyl, such as a C.sub.1-C.sub.10 alkyl, a C.sub.1-C.sub.6 alkyl, a C.sub.1-C.sub.4 alkyl, or a C.sub.1-C.sub.3 alkyl. The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be straight (e.g., n-propyl) or branched (e.g., iso-propyl). The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be unsaturated (e.g., n-butyl) or saturated (e.g., (E)-but-2-enyl). The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can include an aryl moiety. The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be cyclic or non-cyclic. A non-cyclic substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl does not include any ring structures, and a cyclic substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl includes at least one ring structure (e.g., cyclohexyl, cyclopentylmethyl, etc.). A substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be substituted (e.g., mono-substituted, di-substituted, etc.) with a functional group, such as a functional group that includes an oxygen atom. The functional group including an oxygen atom can be any of those known in the art, such as a ketone, ether, alcohol, ester, etc. The substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl can be substituted (e.g., mono-substituted, di-substituted, etc.) with a C.sub.1-C.sub.4 alkyl. When a C.sub.1-C.sub.10 hydrocarbyl is substituted with a substituent that includes one or more carbon atoms, the one or more carbon atoms of the substituent is included in the total count of carbon atoms; therefore, for example, a cyclohexyl substituted with an ethyl group is a C.sub.8 hydrocarbyl.

[0037] In some embodiments, each substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, independently, is selected from methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, phenyl, 3,5-dimethylphenyl, or cyclohexanone.

[0038] In some embodiments, each halogen, independently, is selected from fluoro-, chloro-, or bromo-.

[0039] In some embodiments, R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, methyl, ethyl, iso-propyl, cyclohexanone, phenyl, nitro, sulfonate, sulfonic acid, fluoro-, chloro-, or bromo-. In some embodiments, R.sup.2 is methyl or hydrogen. In some embodiments, R.sup.3, R.sup.4, or both R.sup.3 and R.sup.4 is/are hydrogen.

[0040] In some embodiments, each R.sup.1, independently, is selected from phenyl, tert-butyl, iso-propyl, cyclohexanone, 3,5-dimethylphenyl, or iso-butyl. In some embodiments, each R.sup.1 is phenyl, wherein, optionally, the phenyl is not substituted with one or more halogen atoms, such as a fluorine atom, at the 2-, 3-, 4-, 5-, and/or 6-position.

[0041] In some embodiments, the ligand is of formula (I), wherein each R.sup.1 is phenyl, and each of R.sup.2, R.sup.3, and R.sup.4 is hydrogen. The ligand of formula (I), in some embodiments, has the following structure:

##STR00004##

[0042] In some embodiments, the ligand is of formula (I), wherein each R.sup.1 is phenyl; R.sup.2 is methyl, R.sup.3 is hydrogen, and R.sup.4 is hydrogen. The ligand of formula (I), in some embodiments, has the following structure:

##STR00005##

Methods of Forming Compositions

[0043] Also provided herein are methods of forming compositions, which may include any of the ligands described herein, including the ligands of formula (I).

[0044] The methods of forming compositions can include providing a ligand, such as any of those described herein. The ligand, for example, may be H-PQP, Me-PQP, or any other ligand of formula (I).

[0045] The methods of forming compositions can include providing a metal that is capable of coordinating with a ligand, such as those of formula (I). The metal can be any that is capable of coordinating with a ligand. The metal can include iron (e.g., Fe(I), Fe(II), Fe(III), etc.), cobalt, chromium, nickel, or a combination thereof. Prior to contacting a ligand, a metal can be coordinated with an alkanoate and/or an alkanoic acid, such as octanoate and/or octanoic acid, respectively. The metal can have any oxidation number (e.g., +1, +2, +3, etc.). In some embodiments, the metal has an oxidation number of +3.

[0046] The methods of forming compositions can include contacting a ligand and a metal, wherein the contacting may be effective to coordinate an atom of the metal to the ligand. Generally, a ligand can be contacted with any amount of a metal. In some embodiments, a mole ratio of the metal to the ligand (metal: ligand) during the contacting of the ligand and the metal is about 10:1 to about 1:10, about 8:1 to about 1:8, about 6:1 to about 1:6, about 5:1 to about 1:5, about 4:1 to about 6:1, or about 5:1.

Compositions/Catalysts

[0047] Also provided herein are compositions, which can include any ligand as described herein, such as those of formula (I), and a metal atom, which can be coordinated to the ligand. The compositions, therefore, can include a complex, wherein the complex includes (i) a ligand, such as a ligand of formula (I), and (ii) a metal atom coordinated to the ligand.

[0048] In some embodiments, the compositions include a complex of formula (II):

##STR00006##

[0049] wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are as defined herein; wherein M is a metal atom; and wherein each X, independently, is a halogen. The metal atom M can be any metal capable of coordinating with the ligand, and, in some embodiments, the metal is iron (e.g., Fe(I), Fe(II), Fe(III), etc.), cobalt, chromium, or nickel.

[0050] The compositions provided herein can be a catalyst for a chemical reaction. Although any chemical reaction can be catalyzed by embodiments of the compositions provided herein, the chemical reaction, in some embodiments, includes an oligomerization of olefins.

[0051] The compositions provided herein generally can include one or more additional components, particularly components that do not undesirably impact the properties or effectiveness of the compositions. For example, the composition can also include a co-catalyst. When a co-catalyst is present, it can be present at any amount. In some embodiments, a co-catalyst is present in a composition at a mole ratio of co-catalyst to ligand (co-catalyst: ligand) of about 1,000:0.1 to about 1:0.1, about 1,000:0.1 to about 50:1, about 750:1 to about 50:1, about 750:1 to about 100:1, about 750:1 to about 200:1, about 750:1 to about 300:1, about 750:1 to about 400:1, about 600:1 to about 400:1, about 550:1 to about 450:1, or about 500:1 (for example, if the co-catalyst is an alkyl aluminum, the foregoing ratios can be ratios of aluminum: metal of the ligand). A co-catalyst can include any of those known in the art. In some embodiments, the co-catalyst includes an alkyl aluminum, such as tri-isobutyl aluminum (TIBA), triethylaluminum (TEA), trimethyl aluminum (TMA), methylaluminoxane (MAO), isobutyl-modified methylaluminoxane (MMAO), isobutyl-modified methylaluminoxane (TBA), or a combination thereof.

Methods of Oligomerization

[0052] Also provided herein are methods of oligomerization.

[0053] As used herein, the terms oligomerization, oligomerize, and the like refer to processes that produce a product, which can be referred to herein as an oligomerized product, wherein the product includes oligomers and less than 1 wt % (or less than 0.1 wt %, or less than 0.01 wt %) of polymers, wherein the term oligomers refers to molecules that include no more than 30 carbon atoms, and the term polymers refers to molecules that include more than 30 carbon atoms.

[0054] In some embodiments, the methods of oligomerization include providing a composition, such as any of those provided herein, providing an olefin, and contacting the olefin and the composition. The olefin and the composition can be contacted for a time and at a temperature and a pressure effective to oligomerize at least a portion of the olefin to form an oligomerized product.

[0055] The olefin reactant can include one type of olefin, or two or more different types of olefins. The olefin reactant can include a mono-1-olefin (alpha olefin). The olefin reactant an include from 2 to 10 carbon atoms, 2 to 8 carbon atoms, or 2 to 6 carbon atoms. In some embodiments, the olefin includes ethylene, propylene, 1-butene, 1-hexene, or a combination thereof. The oligomerized product can include a C.sub.4-C.sub.30 oligomer, a C.sub.4-C.sub.26 oligomer, a C.sub.4-C.sub.22 oligomer, a C.sub.4-C.sub.18 oligomer, a C.sub.4-C.sub.16 oligomer, a C.sub.4-C.sub.12 oligomer, a C.sub.4-C.sub.8 oligomer, a C.sub.6-C.sub.30 oligomer, a C.sub.8-C.sub.30 oligomer, a C.sub.10-C.sub.30 oligomer, a C.sub.12-C.sub.30 oligomer, a C.sub.14-C.sub.30 oligomer, a C.sub.16-C.sub.30 oligomer, a C.sub.18-C.sub.30 oligomer, or a C.sub.20-C.sub.30 oligomer.

[0056] The oligomerization reaction can be performed in the presence of one or more other materials or components, such as a co-catalyst. For example, when a composition does not include a co-catalyst, the methods can also include providing a co-catalyst, such as any of those herein, and the contacting of the olefin and the composition can include contacting the olefin, the composition, and the co-catalyst.

[0057] The methods of oligomerization provided herein can be performed at any effective temperature. In some embodiments, the temperature is about 20 C. to about 150 C., about 20 C. to about 100 C., about 20 C. to about 80 C., about 20 C. to about 60 C., about 20 C. to about 40 C., or about 20 C. to about 30 C.

[0058] The methods of oligomerization provided herein can be provided at any effective pressure. In some embodiments, the pressure is about 10 psig to about 1,000 psig, about 10 psig to about 900 psig, about 10 psig to about 800 psig, about 10 psig to about 600 psig, about 10 psig to about 500 psig, about 100 psig to about 500 psig, about 200 psig to about 500 psig, about 300 psig to about 500 psig, about 350 psig to about 450 psig, or about 400 psig. The pressure can be imparted in any manner. In some embodiments, the pressure is imparted by an olefin (for example, the contacting may occur in a vessel, wherein a pressurized stream that includes the olefin is disposed in the vessel). In some embodiments, the contacting of the olefin and the composition occurs under a hydrogen partial pressure, wherein hydrogen can control, at least in part, oligomer molecular weight. The partial pressure of hydrogen can be from about 0 psig to about 2000 psig, about 1 psig to about 1500 psig, about 5 psig to about 1,250 psig, about 10 psig to about 1,000 psig, about 50 psig to above 750 psig, about 100 psig to about 500 psig, about 150 psig to about 400 psig, or from about 200 psig to about 300 psig.

[0059] The methods of oligomerization, particularly the contacting of an olefin and a composition, can occur for any effective time. In some embodiments, the time is about 1 minute to about 60 minutes, about 1 minute to about 50 minutes, about 1 minute to about 40 minutes, about 1 minute to about 30 minutes, about 1 minute to about 20 minutes, about 5 minutes to about 20 minutes, or about 10 minutes to about 20 minutes.

[0060] In some embodiments, an oligomerized product is produced by the methods provided herein at a yield of about 100 g/g.sub.cat to about 500 g/g.sub.cat, about 150 g/g.sub.cat to about 400 g/g.sub.cat, about 100 g/g.sub.cat to about 300 g/g.sub.cat, or about 150 g/g.sub.cat to about 250 g/g.sub.cat.

EXAMPLES

[0061] The disclosure is further illustrated by the following examples, which are not to be construed in any way as imposing limitations to the scope of this technology. Various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, can suggest themselves to one of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the appended claims.

Synthesis of Intermediates and Ligands

Intermediate A. 8-Bromo-2-(2-pyridinyl)quinoline (PQBrH)

##STR00007##

[0062] Compounds 2-amino-3-bromobenzaldehyde (0.9244 g, 4.62 mmol, 1 equiv.), 2-acetylpyridine (0.52 mL, 4.62 mmol, 1 equiv.), and KOH (0.1297 g, 2.31 mmol, 0.5 equiv.) were added to a round bottom flask in dry absolute ethanol (50 mL, dried over mol sieves) under N.sub.2, the reaction was refluxed for 4.5 h. The reaction went from light yellow to a dark yellow/orange. The reaction was cooled to room temperature and solvents were removed in vacuo. Pure material was obtained by washing with absolute EtOH (2 mL, twice) the red filtrate was collected and put in the fridge. Filtration of the material to yield the desired product as a white solid (0.9024 g, 68% yield). .sup.1H NMR (400 MHz, CDCl.sub.3), 8.85 (d, J=7.9, 1H), 8.74-8.72 (m, 1H), 8.66 (d, J=8.6, 1H), 8.28 (d, J=8.6, 1H), 8.07 (dd, J=7.6,1.2, 1H), 7.90 (td, J=7.7, 1.8, 1H), 7.82 (dd, J=8.12, 1.12, 1H), 7.41-7.38 (m, 2H), 1.59 (s, 3H).

Intermediate B. 8-(diphenylphosphino)-2-(2-pyridinyl)quinoline (PQBrMe)

##STR00008##

[0063] Compounds 2-amino-3-bromobenzaldehyde (1.018 g, 5.09 mmol, 1 equiv.), 6-methyl-2-acetylpyridine (0.64 mL, 5.09 mmol, 1 equiv.), and KOH (0.1143 g, 2.04 mmol, 0.5 equiv.) were added to a round bottom flask in dry absolute ethanol (50 mL, dried over mol sieves) under N.sub.2, the reaction was refluxed for 4.5 h. The reaction went from light yellow to a dark yellow/orange. The reaction was cooled to room temperature and solvents were removed in vacuo. Pure material was obtained by washing with absolute EtOH (2 mL, twice) then dissolving the white/yellow solid in CH.sub.2Cl.sub.2. The solution was filtered, the filtrate was collected, and solvents were removed in vacuo to yield the desired product (0.9229 g, 62% yield). .sup.1H NMR (400 MHz, CDCl.sub.3), 8.70 (d, J=8.5, 1H), 8.65 (d, J=7.8, 1H), 8.25 (d, J=8.6, 1H), 8.05 (d, J=2.9, 1H), 7.79 (dd, J=5.91, 1H), 7.38 (t, J=7.78, 1H), 7.24 (d, J=7.56, 1H), 2.67 (s, 3H).

Intermediate C: 8-(diphenylphosphino)-2-(2-pyridinyl)quinoline (PQPphenH)

##STR00009##

[0064] Under an inert atmosphere, a solution of A (PQBrH) (0.3179 g, 1.11 mmol, 1 equiv.) in 10 mL of dry THF was cooled to-40 C. in a round bottom flask. A solution of n-BuLi (0.73 mL, 1.05 equiv.) was added dropwise and the mixture was allowed to stir for 45 minutes, resulting in a dark red solution. Chlorodiphenylphosphine (0.21 mL, 1.28 mmol, 1.05 equiv.) was added at 40 C., the reaction solution lightened, and the mixture was allowed to warm to room temperature. The reaction was stirred overnight, and solvents were removed in vacuo. The black/brown solid was washed with 15 mL of toluene and allowed to stir for 30 minutes and white LiCl precipitate was then removed by filtration over basic alumina. Pure material was obtained by removing the solvent from the collected filtrate in vacuo. The solid was redissolved in toluene, pentane was added to the solution, and the mixture was placed in the freezer overnight to obtain an orange/yellow solid (0.1033 g, 23% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.62 (dd, J=5.5, 4.0, 1H), 8.54 (d, J=8.6, 1H), 8.26 (d, J=8.6, 1H), 8.04 (d, J=8.0, 1H), 7.82 (d, J=8.1, 1H), 7.65 (td, J=7.7, 1.8, 1H), 7.44-7.39 (m, 5H), 7.34-7.32 (m, 6H), 7.25-7.23 (m, 1H), 7.12-7.09 (m, 1H); 31P NMR (202 MHz, CDCl.sub.3), 8-12.8.

8-(diphenylphosphino)-2-(6-methyl-2-pyridinyl)quinoline (PQPphenMe)

##STR00010##

[0065] Under an inert atmosphere, a solution of B (PQBrMe) (0.3192 g, 1.06 mmol, 1 equiv.) in 10 mL of dry THF was cooled to 40 C. in a round bottom flask. A solution of n-BuLi (0.71 mL, 1.05 equiv.) was added dropwise, and the mixture was allowed to stir for 45 minutes, resulting in a dark red solution. Chlorodiphenylphosphine (0.20 mL, 1.23 mmol, 1.05 equiv.) was added at 40 C., the reaction solution lightened, and the mixture was allowed to warm to room temperature. The reaction was stirred overnight, and solvents were removed in vacuo. The yellow solid was washed with 15 mL of toluene and allowed to stir for 30 minutes, and a white LiCl precipitate was then removed by filtration over basic alumina. Pure material was obtained by removing the toluene in vacuo until 3 mL solvent remained. Pentane was added to the solution, and the mixture was placed in the freezer overnight to obtain an orange/yellow solid (0.110 g, 25% yield). .sup.1H NMR (400 MHz, CDCl.sub.3) 8.60 (d, J=8.6, 1H), 8.24 (d, J=8.6, 1H), 7.86 (d, J=7.8, 1H), 7.81 (d, J=8.1, 1H), 7.54 (t, J=7.8, 1H), 7.43-7.39 (m, 5H), 7.33-7.31 (m, 6H), 7.12-7.08 (m, 2H), 2.61 (s, 3H); 31P NMR (202 MHz, CDCl.sub.3), 8-12.6.

Example 1

[0066] In this example, ethylene was oligomerized according to the following procedure and conditions.

TABLE-US-00001 Conditions/Procedure of Example 1 Component Amount Ligand 1.2 mmol [00011] Me-PQP Iron (Fe) Octanoate in C.sub.12 5:1 (Fe:Ligand) Ethylene 400 psig (27.58 bar, gauge pressure; 2.76 MPa, gauge pressure) Modified methylaluminooxane, type 3A 500:1 (Al:Ligand) (MMAO-3A) Nonane 1.0209 g

TABLE-US-00002 Reactor Temperatures of Example 1 Initial Temperature 25 C. Maximum Temperature 33 C. Final Temperature 24 C.

[0067] A nuclear magnetic resonance (NMR) tube was filled with Fe and Me-PQP, and then capped. A charger was filled with 200 mL of cyclohexane, MMAO-3A, and an internal standard (nonane). The NMR tube was then attached to a reactor with a copper wire. The metal reactor body was then attached, and vacuum was applied to pump down the vessel. The contents of the charger were then emptied into the reactor with static vacuum. The vessel was then filled with 400 pounds per square inch (psig) (27.58 bar, gauge pressure; 2.76 MPa, gauge pressure) of ethylene. A stirrer was then turned on to break the NMR tube, which started the reaction. The reaction of this example was run for 15 minutes. The reactor was then vented, and a sample was collected. The reactants and products were analyzed using various techniques and instruments, including gas chromatography (GC).

TABLE-US-00003 Results of Example 1 Product / Result Amounts Polymer Trace Yield (C4-C30 oligomers) 0.0200 g Productivity (g/g catalyst) 39.98 K value 0.55

[0068] The foregoing results indicated a successful and efficient oligomerization of ethylene.

Example 2

[0069] In this example, ethylene was oligomerized according to the following procedure and conditions.

TABLE-US-00004 Conditions/Procedure of Example 2 Component Amount Ligand 1.2 mmol [00012] H-PQP Iron (Fe) Octanoate in C.sub.12 5:1 (Fe:Ligand) Ethylene 400 psig (27.58 bar, gauge pressure; 2.76 MPa, gauge pressure) Modified methylaluminooxane, type 3A 500:1 (Al:Ligand) (MMAO-3A) Nonane 1.0070 g

TABLE-US-00005 Reactor Temperatures of Example 2 Initial Temperature 24 C. Maximum Temperature 33 C. Final Temperature 26 C.

[0070] A nuclear magnetic resonance (NMR) tube was filled with Fe and H-PQP, and then capped. A charger was filled with 200 mL of cyclohexane, MMAO-3A, and an internal standard (nonane). The NMR tube was then attached to a reactor with a copper wire. The metal reactor body was then attached, and vacuum was applied to pump down the vessel. The contents of the charger were then emptied into the reactor with static vacuum. The vessel was then filled with 400 pounds per square inch (psig) (27.58 bar, gauge pressure; 2.76 MPa, gauge pressure) of ethylene. A stirrer was then turned on to break the NMR tube, which started the reaction. The reaction of this example was run for 15 minutes. The reactor was then vented, and a sample was collected. The reactants and products were analyzed using various techniques and instruments, including gas chromatography (GC).

TABLE-US-00006 Results of Example 2 Product / Result Amounts Polymer Trace Yield (C4-C16 oligomers) 0.1765 g Productivity (g/g catalyst) 352.98 K value 0.36

[0071] The foregoing results indicated a successful and efficient oligomerization of ethylene.

ASPECTS

[0072] The following is a non-limiting listing of aspects of the disclosure:

Ligands

[0073] Aspect 1. A ligand of formula (I):

##STR00013##

[0074] wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, nitro (NO.sub.2), sulfonate (SO.sub.3.sup.), sulfonic acid (SO.sub.3H), or a halogen; and wherein, optionally, (a) R.sup.2, (b) R.sup.3, (c) R.sup.4, (d) R.sup.2 and R.sup.3, (e) R.sup.2 and R.sup.4, (f) R.sup.3 and R.sup.4, or (g) R.sup.2, R.sup.3, and R.sup.4 is not hydrogen.

[0075] Aspect 2. The ligand of Aspect 1, wherein the two R.sup.1 substituents are identical.

[0076] Aspect 3. The ligand of Aspect 1, wherein the two R.sup.1 substituents are different.

[0077] Aspect 4. The ligand of any of the preceding aspects, wherein each R.sup.1, independently, is selected from a substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl.

[0078] Aspect 5. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is a C.sub.1-C.sub.10 alkyl, a C.sub.1-C.sub.6 alkyl, a C.sub.1-C.sub.4 alkyl, or a C.sub.1-C.sub.3 alkyl.

[0079] Aspect 6. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is straight or branched.

[0080] Aspect 7. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is unsaturated or saturated.

[0081] Aspect 8. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl comprises an aryl moiety.

[0082] Aspect 9. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is cyclic or non-cyclic.

[0083] Aspect 10. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is substituted (e.g., mono-substituted, di-substituted, etc.) with a functional group comprising an oxygen atom.

[0084] Aspect 11. The ligand of any of the preceding aspects, wherein the functional group comprising an oxygen atom is a ketone.

[0085] Aspect 12. The ligand of any of the preceding aspects, wherein the substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl is substituted (e.g., mono-substituted, di-substituted, etc.) with a C.sub.1-C.sub.4 alkyl.

[0086] Aspect 13. The ligand of any of the preceding aspects, wherein each substituted or unsubstituted C.sub.1-C.sub.10 hydrocarbyl, independently, is selected from methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, phenyl, 3,5-dimethylphenyl, or cyclohexanone.

[0087] Aspect 14. The ligand of any of the preceding aspects, wherein each halogen, independently, is selected from fluoro-, chloro-, or bromo-.

[0088] Aspect 15. The ligand of any of the preceding aspects, wherein R.sup.2, R.sup.3, and R.sup.4, independently, are selected from hydrogen, methyl, ethyl, iso-propyl, cyclohexanone, phenyl, nitro, sulfonate, sulfonic acid, fluoro-, chloro-, or bromo-.

[0089] Aspect 16. The ligand of any of the preceding aspects, wherein each R.sup.1, independently, is selected from phenyl, tert-butyl, iso-propyl, cyclohexanone, 3,5-dimethylphenyl, or iso-butyl.

[0090] Aspect 17. The ligand of any of the preceding aspects, wherein each R.sup.1 is phenyl, wherein, optionally, the phenyl is not substituted with halogen atoms, such as a fluorine atom, at the 2-, 3-, 4-, 5-, and/or 6-position.

[0091] Aspect 18. The ligand of any of the preceding aspects, wherein R.sup.2 is methyl or hydrogen.

[0092] Aspect 19. The ligand of any of the preceding aspects, wherein R.sup.3 is hydrogen.

[0093] Aspect 20. The ligand of any of the preceding aspects, wherein R.sup.4 is hydrogen.

[0094] Aspect 21. The ligand of any of the preceding aspects, wherein the ligand has the following structure:

##STR00014##

[0095] Aspect 22. The ligand of any of the preceding aspects, wherein the ligand has the following structure:

##STR00015##

Methods of Forming Compositions

[0096] Aspect 23. A method of forming a composition, the method comprising, consisting essentially of, or consisting of (i) providing the ligand of any of the preceding aspects, (ii) providing a metal that is capable of coordinating with any ligand of any of the preceding aspects, and (iii) contacting the ligand and the metal, wherein the contacting is effective to coordinate an atom of the metal to the ligand, wherein, optionally, the metal has an oxidation number of +3.

[0097] Aspect 24. The method of any of the preceding aspects, wherein the metal comprises, consists essentially of, or consists of iron (e.g., Fe(I), Fe(II), Fe(III), etc.), cobalt, chromium, nickel, or a combination thereof.

[0098] Aspect 25. The method of any of the preceding aspects, wherein the metal is coordinated with an alkanoate and/or an alkanoic acid prior to, during, and/or after the contacting of the metal and the ligand.

[0099] Aspect 26. The method of any of the preceding aspects, wherein the alkanoate and/or the alkanoic acid comprises, consists essentially of, or consists of octanoate and/or octanoic acid, respectively.

[0100] Aspect 27. The method of any of the preceding aspects, wherein a mole ratio of the metal to the ligand (metal: ligand) during the contacting of the ligand and the metal is about 10:1 to about 1:10, about 8:1 to about 1:8, about 6:1 to about 1:6, about 5:1 to about 1:5, about 4:1 to about 6:1, or about 5:1.

Catalysts

[0101] Aspect 28. A composition comprising, consisting essentially of, or consisting of a complex, wherein the complex comprises, consists essentially of, or consists of (i) a ligand of any of the preceding aspects, and (ii) a metal, wherein an atom of the metal is coordinated to the ligand.

[0102] Aspect 29. A composition made according to the method of any of the preceding aspects.

[0103] Aspect 30. The composition of any of the preceding aspects, wherein the composition is a catalyst for a chemical reaction, wherein the chemical reaction is an oligomerization of olefins.

[0104] Aspect 31. The composition of any of the preceding aspects, wherein the complex comprises, consists essentially of, or consists of a complex of formula (II):

##STR00016##

[0105] wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are as defined by any of the preceding aspects; wherein M is a metal atom; wherein each X, independently, is a halogen; and wherein, optionally, (a) R.sup.2, (b) R.sup.3, (c) R.sup.4, (d) R.sup.2 and R.sup.3, (e) R.sup.2 and R.sup.4, (f) R.sup.3 and R.sup.4, or (g) R.sup.2, R.sup.3, and R.sup.4 is not hydrogen.

[0106] Aspect 32. The composition of any of the preceding aspects, wherein M is Fe(I) or Fe(III).

[0107] Aspect 33. The composition of any of the preceding aspects, wherein the composition further comprises, consists essentially of, or consists of a co-catalyst.

[0108] Aspect 34. The composition of any of the preceding aspects, wherein the co-catalyst is present in the composition at a mole ratio of co-catalyst to ligand (co-catalyst: ligand) of about 1,000:0.1 to about 1:0.1, about 1,000:0.1 to about 50:1, about 750:1 to about 50:1, about 750:1 to about 100:1, about 750:1 to about 200:1, about 750:1 to about 300:1, about 750:1 to about 400:1, about 600:1 to about 400:1, about 550:1 to about 450:1, or about 500:1 (for example, if the co-catalyst is an alkyl aluminum, the foregoing ratios can be ratios of aluminum: metal of the ligand).

[0109] Aspect 35. The composition of any of the preceding aspects, wherein the co-catalyst comprises, consists essentially of, or consists of an alkyl aluminum.

[0110] Aspect 36. The composition of any of the preceding aspects, wherein the co-

[0111] catalyst comprises, consists essentially of, or consists of tri-isobutyl aluminum (TIBA), triethylaluminum (TEA), trimethyl aluminum (TMA), methylaluminoxane (MAO), isobutyl-modified methylaluminoxane (MMAO), isobutyl-modified methylaluminoxane (TBA), or a combination thereof.

Methods of Oligomerization

[0112] Aspect 37. A method of oligomerization, the method comprising, consisting essentially of, or consisting of (i) providing a composition of any of the preceding aspects, (ii) providing an olefin, and (iii) contacting the olefin and the composition for a time and at a temperature and a pressure effective to oligomerize at least a portion of the olefin to form an oligomerized product.

[0113] Aspect 38. The method of any of the preceding aspects, wherein when the composition does not include a co-catalyst, the method further comprises, consists essentially of, or consists of providing a co-catalyst, such as any of those of the preceding aspects, and the contacting of the olefin and the composition further comprises, consists essentially of, or consists of contacting the olefin, the composition, and the co-catalyst.

[0114] Aspect 39. The method of any of the preceding aspects, wherein when the composition does not include a co-catalyst, the method further comprises, consists essentially of, or consists of providing a co-catalyst, such as any of those of the preceding aspects, and contacting the olefin and the co-catalyst.

[0115] Aspect 40. The method of any of the preceding aspects, wherein the temperature is about 20 C. to about 150 C., about 20 C. to about 100 C., about 20 C. to about 80 C., about 20 C. to about 60 C., about 20 C. to about 40 C., or about 20 C. to about 30 C.

[0116] Aspect 41. The method of any of the preceding aspects, wherein the pressure is about 10 psig to about 1,000 psig, about 10 psig to about 900 psig, about 10 psig to about 800 psig, about 10 psig to about 600 psig, about 10 psig to about 500 psig, about 100 psig to about 500 psig, about 200 psig to about 500 psig, about 300 psig to about 500 psig, about 350 psig to about 450 psig, or about 400 psig.

[0117] Aspect 42. The method of any of the preceding aspects, wherein the pressure is imparted by the olefin (for example, the contacting may occur in a vessel, wherein a pressurized stream comprising the olefin is disposed in the vessel).

[0118] Aspect 43. The method of any of the preceding aspects, wherein the contacting of the olefin and the composition occurs under a hydrogen partial pressure, wherein hydrogen can control, at least in part, oligomer molecular weight.

[0119] Aspect 44. The method of any of the preceding aspects, wherein the partial pressure of hydrogen is from about 0 psig to about 2000 psig, about 1 psig to about 1500 psig, about 5 psig to about 1,250 psig, about 10 psig to about 1,000 psig, about 50 psig to above 750 psig, about 100 psig to about 500 psig, about 150 psig to about 400 psig, or from about 200 psig to about 300 psig.

[0120] Aspect 45. The method of any of the preceding aspects, wherein the time is about 1 minute to about 60 minutes, about 1 minute to about 50 minutes, about 1 minute to about 40 minutes, about 1 minute to about 30 minutes, about 1 minute to about 20 minutes, about 5 minutes to about 20 minutes, or about 10 minutes to about 20 minutes.

[0121] Aspect 46. The method of any of the preceding aspects, wherein the olefin comprises, consists essentially of, or consists of two or more different types of olefins.

[0122] Aspect 47. The method of any of the preceding aspects, wherein the olefin comprises, consists essentially of, or consists of a mono-1-olefin (alpha olefin).

[0123] Aspect 48. The method of any of the preceding aspects, wherein the olefin comprises from 2 to 10 carbon atoms, 2 to 8 carbon atoms, or 2 to 6 carbon atoms.

[0124] Aspect 49. The method of any of the preceding aspects, wherein the olefin comprises, consists essentially of, or consists of ethylene, propylene, 1-butene, 1-hexene, or a combination thereof.

[0125] Aspect 50. The method of any of the preceding aspects, wherein the oligomerized product comprises, consists essentially of, or consists of a C.sub.4-C.sub.30 oligomer, a C.sub.4-C.sub.26 oligomer, a C.sub.4-C.sub.22 oligomer, a C.sub.4-C.sub.18 oligomer, a C.sub.4-C.sub.16 oligomer, a C.sub.4-C.sub.12 oligomer, a C.sub.4-C.sub.8 oligomer, a C.sub.6-C.sub.30 oligomer, a C.sub.8-C.sub.30 oligomer, a C.sub.10-C.sub.30 oligomer, a C.sub.12-C.sub.30 oligomer, a C.sub.14-C.sub.30 oligomer, a C.sub.16-C.sub.30 oligomer, a C.sub.18-C.sub.30 oligomer, or a C.sub.20-C.sub.30 oligomer.

[0126] Aspect 51. The method of any of the preceding aspects, wherein the oligomerized product is produced at a yield of about 100 g/g.sub.cat to about 500 g/g.sub.cat, about 150 g/g.sub.cat to about 400 g/g.sub.cat, about 100 g/g.sub.cat to about 300 g/g.sub.cat, or about 150 g/g.sub.cat to about 250 g/g.sub.cat.