Metal complexes

Abstract

The present invention provides novel metal complexes, methods of making, and methods of using the same.

Claims

1. A metallosalenate complex comprising a cationic bicyclic amidinium group, wherein the cationic bicyclic amidinium group has no free amines, and wherein the metallosalenate complex is of formula: ##STR00035## wherein, R.sup.1a and R.sup.1a′ are independently a hydrogen or an optionally substituted radical selected from the group consisting of C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; each R.sup.d is independently a -L-CA group, halogen, —OR, —NR.sub.2, —SR, —CN, —NO.sub.2, —SO.sub.2R, —SOR, —SO.sub.2NR.sub.2, —CNO, —CO.sub.2R, —CON(R).sub.2, —OC(O)NR.sub.2, —OC(O)OR, —NRSO.sub.2R, —NCO, —N.sub.3, —SiR.sub.3; or an optionally substituted radical selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; where two or more R.sup.d groups may be taken together with intervening atoms to form one or more optionally substituted rings optionally containing one or more heteroatoms; each -L- is independently a covalent bond or an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-12 hydrocarbon chain, wherein one or more methylene units of -L- are optionally and independently replaced by -Cy-, —CR.sub.2—, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO.sub.2—, —SO.sub.2N(R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR.sub.2—, —S—, —SO—, or —SO.sub.2—; each -CA is independently a cationic bicyclic amidinium group having no free amines; each Cy is independently an optionally substituted bivalent ring selected from phenylene, a 3-7 membered saturated or partially unsaturated carbocyclylene, a 3-7 membered saturated or partially unsaturated monocyclic heterocyclylene having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or a 5-6 membered heteroarylene having 1-3 heteroatoms independently selected from nitrogen or oxygen; R.sup.4b is selected from the group consisting of: ##STR00036## R.sup.c at each occurrence is independently hydrogen, halogen, —OR, —NR.sub.2, —SR, —CN, —NO.sub.2, —SO.sub.2R, —SOR, —SO.sub.2NR.sub.2, —CNO, —CO.sub.2R, —CON(R).sub.2, —OC(O)NR.sub.2, —OC(O)OR, —NRSO.sub.2R, —NCO, —N.sub.3, —SiR.sub.3; or an optionally substituted radical selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; where two or more R.sup.c groups may be taken together with the carbon atoms to which they are attached and any intervening atoms to form one or more optionally substituted rings; R at each occurrence is independently hydrogen, an optionally substituted radical selected the group consisting of acyl; C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; carbamoyl; arylalkyl; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; an oxygen protecting group; and a nitrogen protecting group, where two R groups on the same nitrogen atom can optionally be taken together to form an optionally substituted 3- to 7-membered ring; T is a divalent linker selected from the group consisting of: —NR—, —N(R)C(O)—, —C(O)NR—, —O—, —C(O)—, —OC(O)—, —C(O)O—, —S—, —SO—, —SO.sub.2—, —SiR.sub.2—, —C(═S)—, —C(═NR)—, or —N═N—; a polyether; a C.sub.3 to C.sub.8 substituted or unsubstituted carbocycle; and a C.sub.1 to C.sub.8 substituted or unsubstituted heterocycle; M is a metal atom; each X is independently selected from the group consisting of halide, perchlorate, borates, sulfonates, sulfates, phosphates, phenolates, carbonates, carboxylates, —OR.sup.x, —O(C═O)R.sup.x, —O(C═O)OR.sup.x, —O(C═O)N(R.sup.x).sub.2, —NC, —CN, —NO.sub.3, halogen, —N.sub.3, —O(SO.sub.2)R.sup.x and —OPR.sup.x.sub.3, wherein each R.sup.x is, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl and optionally substituted heteroaryl; k is 1 or 2; m is from 0 to 6, inclusive; m′ is from 0 to 4, inclusive; q is from 0 to 4, inclusive; and x is from 0 to 2, inclusive.

2. The metallosalenate complex of claim 1, wherein the metallosalenate complex is of formula II or II-a: ##STR00037##

3. The metallosalenate complex of claim 2, wherein the metallosalenate complex is of formula: ##STR00038## ##STR00039## ##STR00040##

4. The metallosalenate complex of claim 1, wherein R.sup.1a and R.sup.1a′ are hydrogen.

5. The metallosalenate complex of claim 1, wherein M is selected from the group consisting of Cr, Mn, V, Fe, Co, Mo, W, Ru, Al, and Ni.

6. The metallosalenate complex of claim 5, wherein one occurrence of R.sup.d is a -L-CA group, and any other R.sup.d groups are an optionally substituted C.sub.1-20 aliphatic group or an optionally substituted phenyl group.

7. The metallosalenate complex of claim 1, wherein -L- is an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-6 hydrocarbon chain, wherein one, two, or three methylene units of L are optionally and independently replaced by -Cy-, —CR.sub.2—, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO.sub.2—, —SO.sub.2N(R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR.sub.2—, —S—, —SO—, or —SO.sub.2—.

8. The metallosalenate complex of claim 7, wherein -L- is an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-6 hydrocarbon chain, wherein one or two methylene units of L are optionally and independently replaced by —NR—, —O—, or —C(O)—.

9. The metallosalenate complex of claim 8, wherein -L- is —(CH.sub.2).sub.1-6—.

10. The metallosalenate complex of claim 1, wherein -L- is selected from the group consisting of: ##STR00041## ##STR00042## where * represents the site of attachment to the salen ligand, each # represents a site of attachment to the amidinium group, and R.sup.y is —H, or an optionally substituted radical selected from the group consisting of C.sub.1-6 aliphatic, 3- to 7-membered heterocyclic, phenyl, and 8- to 10-membered aryl.

11. The metallosalenate complex of claim 7, wherein CA is selected from the group consisting of: ##STR00043##

12. The metallosalenate complex of claim 1, wherein the ligand portion of the metal complex comprises a substructure selected from the group consisting of: ##STR00044## ##STR00045##

13. The metallosalenate complex of claim 1, wherein the metal complex is of formula III: ##STR00046## wherein: Y, when present, is a suitable counterion; wherein when k is 2, Y is absent and X comprises two monodentate moieties or a single bidentate moiety, and when k is 1, X comprises a monodentate moiety; or X and Y are taken together to comprise a suitable dianion.

14. The metallosalenate complex of claim 13, wherein the metal complex is of formula III-a: ##STR00047##

15. The metallosalenate complex of claim 13, wherein Y is selected from the group consisting of halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, alkyl sulfonate, and aryl sulfonate.

16. The metallosalenate complex of claim 15, wherein Y is chloro, bromo, or iodo.

17. The metallosalenate complex of claim 16, wherein Y is chloro.

18. The metallosalenate complex of claim 1, wherein X is carbonate.

19. The metallosalenate complex of claim 1, wherein k is 1.

20. The metallosalenate complex of claim 1, wherein k is 2.

21. The metallosalenate complex of claim 20, wherein X is carbonate.

22. The metallosalenate complex of claim 1, wherein M is cobalt.

23. The metallosalenate complex of claim 13 having the structure: ##STR00048##

24. A method comprising the step of contacting an epoxide and carbon dioxide with a metallosalenate complex of claim 1 to form a polycarbonate polymer composition, wherein the polycarbonate polymer composition is substantially free of covalently-bound metal complex or any portion thereof.

25. A method comprising the steps of: i. contacting an epoxide and carbon dioxide with a metal complex claim 1 to form a polycarbonate polymer composition; and ii. performing chromatography, filtration, or precipitation to obtain isolated polycarbonate polymer composition.

26. The method of claim 25, wherein the isolated polycarbonate polymer composition is pure.

27. The method of claim 25, wherein the isolated polycarbonate polymer composition is substantially free of the metal complex or any portion thereof.

28. A method comprising the steps of: i. contacting an epoxide and carbon dioxide with a metal complex of claim 1 to form a polycarbonate polymer composition; and ii. performing chromatography to obtain substantially isolated, intact metal complex.

Description

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

(1) The present invention encompasses the recognition that there remains a need for metal complexes that have improved reaction and/or product purity characteristics. The present invention provides, among other things, new metal complexes that do not form permanent covalent bonds with the polymer product. Thus, the present invention provides metal complexes that, compared to certain known metal complexes, are more easily separated from the polymerization product.

(2) Certain transition metal complexes having a salen-type ligand and a tethered bicyclic guanidine group have been shown to be superior catalysts for the copolymerization of epoxides and carbon dioxide (WO2010/022388). It has been observed by Applicant and others that such complexes, or portions thereof, have a tendency to form covalent bonds with the polymer chain during polymerization, complicating purification of the polymer product. While not wishing to be bound by any particular theory, Applicant proposes the possibility that when a bicyclic guanidine moiety, including but not limited to 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), is tethered to the metal complex, the remaining secondary amine group of the bicyclic guanidine group can form a covalent bond with the polymer chain. One possibility of a resulting covalently bound complex is:

(3) ##STR00002##

(4) Applicant has also observed that upon quenching certain polymerization processes (e.g., those catalyzed by a metal complex having a secondary amine group) and treating with sulfonic acid ion exchange resins, catalyst fragments may be bound to the polymer chain. Such bound fragments may impart undesirable characteristics to the polymer composition, including but not limited to a yellow color. In some embodiments, such bound fragments are portions of the metal complex ligands. One possible depiction of such a bound ligand fragment is:

(5) ##STR00003##

(6) Applicant describes herein that replacement of the guanidine group with an amidine group, thereby removing the secondary amine group, prevents the undesirable covalent binding of the metal complex (or fragmented ligand thereof) to the polymer.

(7) Prior to the teachings described herein, those of ordinary skill in the art understood that metal catalysts containing a tethered TBD moiety offered certain advantages for the synthesis of polycarbonates. Against this backdrop, the present disclosure presents surprising evidence of the usefulness and effectiveness of modifying the TBD moiety such that covalent binding to the polymer is prevented.

(8) The present invention provides, among other things, methods for polymerizing an epoxide and carbon dioxide with a provided metal complex to form a polycarbonate polymer composition, wherein the polycarbonate polymer composition is substantially free of covalently-bound metal complex or any amidine-containing portion thereof. In some embodiments, chromatography is used to obtain an isolated polycarbonate polymer composition. In some embodiments, the isolated polycarbonate polymer composition is substantially free of the metal complex or any amidine-containing portion thereof.

(9) The present invention provides, among other things, methods for obtaining substantially isolated, intact metal complexes of the present invention following polymerization of an epoxide and carbon dioxide with a provided metal complex.

(10) In some embodiments, the present invention provides a metallosalenate complex comprising a cationic bicyclic amidinium group, wherein the cationic bicyclic amidinium group has no free amines. The term “no free amines”, as used herein, refers to an amidinium group having no nitrogen atoms bearing a hydrogen in any tautomeric or resonance form. In some embodiments, an amidinium group having no free amines has one nitrogen atom bearing three nonhydrogen substituents and a second nitrogen atom with bonds to four nonhydrogen substituents. In some embodiments, such nonhydrogen substituents are aliphatic substituents. In some embodiments, such nonhydrogen substituents comprise the rings of the bicyclic amidinium group. In some embodiments, an amidinium group having no free amines is cationic, as compared to a neutral amidinium group having a free amine.

(11) It will be appreciated that when an amidinium cation is drawn in a particular fashion herein, all resonance forms are contemplated and encompassed by the present disclosure. For example, the group:

(12) ##STR00004##
may also be depicted as

(13) ##STR00005##

(14) In some embodiments, the present invention provides a metallosalenate complex of formula I:

(15) ##STR00006##
wherein, R.sup.1a and R.sup.1a′ are independently a hydrogen or an optionally substituted radical selected from the group consisting of C.sub.1-12 aliphatic; C.sub.1-12 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; each R.sup.d is independently a -L-CA group, halogen, —OR, —NR.sub.2, —SR, —CN, —NO.sub.2, —SO.sub.2R, —SOR, —SO.sub.2NR.sub.2, —CNO, —CO.sub.2R, —CON(R).sub.2, —OC(O)NR.sub.2, —OC(O)OR, —NRSO.sub.2R, —NCO, —N.sub.3, —SiR.sub.3; or an optionally substituted radical selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; where two or more R.sup.d groups may be taken together with intervening atoms to form one or more optionally substituted rings optionally containing one or more heteroatoms, wherein at least one occurrence of R.sup.d is a -L-CA group; each L is independently a covalent bond or an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-12 hydrocarbon chain, wherein one or more methylene units of L are optionally and independently replaced by -Cy-, —CR.sub.2—, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO.sub.2—, —SO.sub.2N(R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR.sub.2—, —S—, —SO—, or —SO.sub.2—; each CA is independently a cationic bicyclic amidinium group having no free amines; each Cy is independently an optionally substituted bivalent ring selected from phenylene, a 3-7 membered saturated or partially unsaturated carbocyclylene, a 3-7 membered saturated or partially unsaturated monocyclic heterocyclylene having 1-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or a 5-6 membered heteroarylene having 1-3 heteroatoms independently selected from nitrogen, oxygen; R.sup.4b is selected from the group consisting of:

(16) ##STR00007##
where R.sup.c at each occurrence is independently hydrogen, halogen, —OR, —NR.sub.2, —SR, —CN, —NO.sub.2, —SO.sub.2R, —SOR, —SO.sub.2NR.sub.2, —CNO, —CO.sub.2R, —CON(R).sub.2, —OC(O)NR.sub.2, —OC(O)OR, —NRSO.sub.2R, —NCO, —N.sub.3, —SiR.sub.3; or an optionally substituted radical selected from the group consisting of C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; where two or more R.sup.c groups may be taken together with the carbon atoms to which they are attached and any intervening atoms to form one or more optionally substituted rings; R at each occurrence is independently hydrogen, an optionally substituted radical selected the group consisting of acyl; C.sub.1-20 aliphatic; C.sub.1-20 heteroaliphatic; carbamoyl; arylalkyl; phenyl; a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle; a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; an oxygen protecting group; and a nitrogen protecting group, where two R groups on the same nitrogen atom can optionally be taken together to form an optionally substituted 3- to 7-membered ring; T is a divalent linker selected from the group consisting of: —NR—, —N(R)C(O)—, —C(O)NR—, —O—, —C(O)—, —OC(O)—, —C(O)O—, —S—, —SO—, —SO.sub.2—, —SiR.sub.2—, —C(═S)—, —C(═NR)—, or —N═N—; a polyether; a C.sub.3 to C.sub.8 substituted or unsubstituted carbocycle; and a C.sub.1 to C.sub.8 substituted or unsubstituted heterocycle; M is a metal atom; each X is independently a suitable counterion; k is from 0 to 2, inclusive; m is from 0 to 6, inclusive; m′ is from 0 to 4, inclusive; q is from 0 to 4, inclusive; and x is from 0 to 2, inclusive.

(17) In certain embodiments, the present invention provides a metallosalenate complex of formula II:

(18) ##STR00008##
wherein each of k, m, q, L, CA, R.sup.c, R.sup.d, M, and X are as defined above and described in classes and subclasses herein, both singly and in combination.

(19) In certain embodiments, the present invention provides a metallosalenate complex of formula II-a:

(20) ##STR00009##
wherein each of k, m, q, L, CA, R.sup.c, R.sup.d, M, and X are as defined above and described in classes and subclasses herein, both singly and in combination.

(21) In certain embodiments, the present invention provides a metallosalenate complex of formula II-aa, II-bb, II-cc, II-dd, II-ee, II-ff, II-gg, or II-hh:

(22) ##STR00010## ##STR00011##
wherein each of k, m, q, L, CA, R.sup.c, R.sup.d, M, and X are as defined above and described in classes and subclasses herein, both singly and in combination.

(23) In certain embodiments, the present invention provides a metallosalenate complex of formula II-ii, II-jj, II-kk, II-ll, or II-mm:

(24) ##STR00012##
wherein each of k, m, q, L, CA, R.sup.c, R.sup.d, M, and X are as defined above and described in classes and subclasses herein, both singly and in combination.

(25) In certain embodiments, the present invention provides a metallosalenate complex of formula III:

(26) ##STR00013##
wherein each of k, M, and X are as defined above and described in classes and subclasses herein, both singly and in combination; and
Y, when present, is a suitable counterion; wherein when k is 2, Y is absent and X comprises two monodentate moieties or a single bidentate moiety, or X and Y are taken together to comprise a suitable dianion.

(27) In some embodiments, the present invention provides a metallosalenate complex of formula III-a:

(28) ##STR00014##
wherein each of k, M, X, and Y are as defined above and described in classes and subclasses herein, both singly and in combination. In certain embodiments, complexes of formula III-a are racemic. In certain embodiments, complexes of formula III-a are non-racemic (i.e., the complex is enantioenriched or enantiopure).

(29) In certain embodiments, the present invention provides a metallosalenate complex of formula IV:

(30) ##STR00015##
wherein each of k, M, X, and Y are as defined above and described in classes and subclasses herein, both singly and in combination.

(31) In certain embodiments, the present invention provides a metallosalenate complex of formula IV-a:

(32) ##STR00016##
wherein each of k, M, X, and Y are as defined above and described in classes and subclasses herein, both singly and in combination. In certain embodiments, complexes of formula IV-a are racemic. In certain embodiments, complexes of formula IV-a are non-racemic (i.e., the complex is enantioenriched or enantiopure).

(33) In some embodiments, a metal atom, M, is selected from periodic table groups 3-13, inclusive. In certain embodiments, M is a transition metal selected from periodic table groups 5-12, inclusive. In some embodiments, M is a transition metal selected from periodic table groups 4-11, inclusive. In certain embodiments, M is a transition metal selected from periodic table groups 5-10, inclusive. In certain embodiments, M is a transition metal selected from periodic table groups 7-9, inclusive. In some embodiments, M is selected from the group consisting of Cr, Mn, V, Fe, Co, Mo, W, Ru, Al, and Ni. In some embodiments, M is a metal atom selected from the group consisting of: cobalt; chromium; aluminum; titanium; ruthenium, and manganese. In some embodiments, M is cobalt. In some embodiments, M is chromium. In some embodiments, M is aluminum. In certain embodiments where a metallosalenate complex is a cobalt complex, the cobalt metal has an oxidation state of +3 (i.e., Co(III)). In other embodiments, the cobalt metal has an oxidation state of +2 (i.e., Co(II)).

(34) In some embodiments R.sup.1a and R.sup.1a′ are hydrogen.

(35) In some embodiments, one occurrence of R.sup.d is a -L-CA group, and any other R.sup.d groups are optionally substituted C.sub.1-20 aliphatic groups or an optionally substituted phenyl group.

(36) In some embodiments, two occurrences of R.sup.d are a -L-CA group, and any other R.sup.d groups are optionally substituted C.sub.1-20 aliphatic groups or an optionally substituted phenyl group. In certain embodiments, the two -L-CA groups are appended to the same salicylaldehyde aryl ring. In certain embodiments, the two -L-CA groups are to different salicylaldehyde aryl rings. In certain embodiments, the two -L-CA groups are appended to different salicylaldehyde aryl rings such that the resulting complex is C2-symmetric. In some embodiments, where a metal complex has multiple -L-CA groups, each -L-CA group is the same. In some embodiments, where a metal complex has multiple -L-CA groups, at least one -L-CA group is different from other -L-CA groups.

(37) In certain embodiments, -L- is an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-12 hydrocarbon chain, wherein one, two, or three methylene units of L are optionally and independently replaced by -Cy-, —CR.sub.2—, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO.sub.2—, —SO.sub.2N(R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR.sub.2—, —S—, —SO—, or —SO.sub.2—. In certain embodiments, -L- is an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-6 hydrocarbon chain, wherein one, two, or three methylene units of L are optionally and independently replaced by -Cy-, —CR.sub.2—, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO.sub.2—, —SO.sub.2N(R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR.sub.2—, —S—, —SO—, or —SO.sub.2—. In some embodiments, -L- is an optionally substituted, saturated or unsaturated, straight or branched, bivalent C.sub.1-6 hydrocarbon chain, wherein one or two methylene units of L are optionally and independently replaced by —NR—, —O—, or —C(O)—.

(38) In some embodiments, -L- is a straight or branched, saturated or unsaturated, bivalent C.sub.1-12 hydrocarbon chain. In some embodiments, -L- is a straight or branched, saturated or unsaturated, bivalent C.sub.1-6 hydrocarbon chain. In some embodiments, -L- is —(CH.sub.2).sub.6—. In some embodiments, -L- is —(CH.sub.2).sub.5—. In some embodiments, -L- is —(CH.sub.2).sub.4—. In some embodiments, -L- is —(CH.sub.2).sub.3—. In some embodiments, -L- is —(CH.sub.2).sub.2—. In some embodiments, -L- is —(CH.sub.2)—.

(39) In some embodiments, -L- is selected from the group consisting of:

(40) ##STR00017## ##STR00018##
where * represents the site of attachment to the salen ligand, each # represents a site of attachment amidinium group, and R.sup.y is —H, or an optionally substituted radical selected from the group consisting of C.sub.1-6 aliphatic, 3- to 7-membered heterocyclic, phenyl, and 8- to 10-membered aryl. In certain embodiments, R.sup.y is other than —H.

(41) In some embodiments, -L- is selected from the group consisting of:

(42) ##STR00019##
wherein s, t, *, and # are each as defined above.

(43) In certain embodiments, -CA is selected from the group consisting of:

(44) ##STR00020##

(45) In certain embodiments, the ligand portion of provided metallosalenate complexes contains a substructure selected from the group consisting of:

(46) ##STR00021## ##STR00022##
wherein -L-CA is as defined above and described in classes and subclasses herein.

(47) In some embodiments, k is 0. In some embodiments, k is 1. In some embodiments, k is 2.

(48) In some embodiments, X and Y are independently a suitable counterion. Suitable counterions for such metal complexes are known in the art and refer to an anion or cation suitable to balance the charge. In some embodiments, a suitable counterion is an anion. In some embodiments, a suitable anion is selected from the group consisting of halide, a complex inorganic ion (e.g., perchlorate), borates, sulfonates, sulfates, phosphates, phenolates, carbonates, and carboxylates. In some embodiments, X and Y are independently halide, hydroxide, carboxylate, sulfate, phosphate, —OR.sup.x, —O(C═O)R.sup.x, —NC, —CN, —NO.sub.3, —N.sub.3, —O(SO.sub.2)R.sup.x and —OP(R.sup.x).sub.3, wherein each R.sup.x is, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl and optionally substituted heteroaryl.

(49) It will be appreciate that in some cases, a metallosalenate complex initially comprises both a X and Y counterion, but the Y counterion is later displaced by a bidentate X counterion or a second monodentate X ligand, thereby maintaining the proper charge balance on the metallosalenate complex.

(50) In some embodiments, k is 2 and X comprises two monodentate moieties. In some embodiments, k is 2 and X comprises a single bidentate moiety. In some embodiments, k is 2, Y is absent and X comprises a single bidentate moiety. In some embodiments, Y is absent. In some embodiments, X is carbonate.

(51) In some embodiments, X and Y are taken together and comprise a dianion. In some embodiments, X and Y together form a diacid. In some embodiments, X and Y together form a dicarboxylic acid.

(52) In some embodiments, Y is selected from the group consisting of halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, alkyl sulfonate, and aryl sulfonate.

(53) In some embodiments, X and Y are independently hydrogen phosphate, sulfate, a halide or carbonate. In some embodiments, X is carbonate. In some embodiments, Y is chloro, bromo, or iodo. In some embodiments, Y is chloro.

(54) In some embodiments, M is cobalt, -L- is a bivalent C.sub.1-6 hydrocarbon chain, -CA is selected from the group consisting of:

(55) ##STR00023##
wherein X is carbonate, and k is 1.

(56) In some embodiments of compounds of formula III-a: M is a metal atom; k is from 0-2; and X and Y are each independently a suitable counterion, wherein when k is 1, X comprises a monodentate moiety; or X and Y are taken together to comprise a suitable dianion.

(57) In certain embodiments, where X and Y are taken together to form a dianion, and M is cobalt, a formal negative charge may be placed on the cobalt atom. An example of such a case is a provided metallosalenate complex having the structure:

(58) ##STR00024##

(59) Provided metal complexes allow for the polymerization of epoxides and carbon dioxide while avoiding or lessening covalent binding of the metal complex to the polymer. In some embodiments, the present invention provides a method comprising the step of contacting an epoxide or mixture of epoxides and carbon dioxide with a provided metallosalenate complex to form a polycarbonate polymer composition, wherein the polycarbonate polymer composition is substantially free of covalently-bound metallosalenate complex or any portion thereof.

(60) In certain embodiments, the present invention provides a method comprising the steps of: i. contacting an epoxide and carbon dioxide with a metallosalenate complex to form a polycarbonate polymer composition; and ii. performing chromatography, filtration, or precipitation to obtain isolated polycarbonate polymer composition.
In some embodiments, an isolated polycarbonate polymer composition is pure. In some embodiments, an isolated polycarbonate polymer composition is 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% pure. In some embodiments, an isolated polycarbonate polymer composition is substantially free of the metallosalenate complex or any portion thereof.

(61) In some embodiments, the present invention provides a method comprising the steps of: i. contacting an epoxide and carbon dioxide with a metallosalenate complex to form a polycarbonate polymer composition; and ii. performing chromatography to obtain substantially isolated, intact metallosalenate complex.

EXEMPLIFICATION

Example 1

(62) This example describes the synthesis of catalyst A.

(63) ##STR00025##

(64) A 10 wt % ethanolic solution of aldehyde 6 (6 is made according to Example 9 of WO 2012/040454, substituting 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)), is contacted with an equimolar amount of the known ammonium salt 7 (described in Chemical Communications (2010), 46(17), 2935-2937) in the presence of NaOH to provide ligand 8. The ligand is treated with cobalt(II) acetate to afford the cobalt(II) complex and liberate two equivalents of acetic acid. This complex is oxidized in the presence of air to provide the desired catalyst.

Example 2

(65) This example describes the synthesis of additional catalysts of the present invention having alternate substitution patterns on the aryl rings of the salcy ligands. Compounds 2a through 2n are synthesized according to conditions of Example 1, except ammonium salts with alternate substitution patterns on the aryl ring are employed in place of the 2,4-di-t-butyl analog 7 used in Example 1. Compounds 2o through 2q are synthesized according to conditions of Example 1, except that 1,8-diazabicyclo[5.4.0]undec-7-ene is substituted with 1,5-diazabicyclo[4.3.0]non-5-ene. The required ammonium salts are obtained by condensing racemic trans 1,2 cyclohexanediamine monohydrochloride with salicaldehyde analogs having the desired substituents at the 2- and/or 4-positions. In each example, the catalyst is isolated as its carbonate salt, (i.e. X and Y are taken together to be CO.sub.3.sup.2−).

(66) ##STR00026## ##STR00027## ##STR00028## ##STR00029## ##STR00030## ##STR00031##

Example 3

(67) This example describes the synthesis of catalysts of the present invention having alternate bridging groups between the imine nitrogen atoms of the salen ligands. Catalysts 3a and 3d through 3f are produced according to the method of Example 1, except the required ligand is made by sequential addition of the appropriate salicylaldehyde and aldehyde 6 to isobutylene diamine in the presence of 3-angstrom molecular sieves.

(68) Catalysts 4b and 4c are produced according to the method of Example 1, by condensing aldehyde 6 with appropriate hydrochloride salts analogous to the 1,2 cyclohexane diamine-derived salt 7 used in Example 1. The required hydrochloride salts are produced in a separate step by sequential addition of one equivalent of HCl, and one equivalent of 2,4-di-tert butyl salicylaldehyde to ethylene diamine (3b) or 1,3 diaminopropane (3c).

(69) ##STR00032## ##STR00033##

Example 4

(70) An alternative synthesis of Catalyst A is depicted in the scheme below.

(71) ##STR00034##

Other Embodiments

(72) The foregoing has been a description of certain nonlimiting embodiments of the invention. Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.