Metal complexes

1. A metallosalenate complex comprising a cationic bicyclic guanidinium group, wherein the cationic bicyclic guanidinium group has no free amines.

2. The metallosalenate complex of claim 1 , wherein the metallosalenate complex is of formula I:

wherein,

R 1a and R 1a′ independently a hydrogen or an optionally substituted radical selected from the group consisting of C 1-12 aliphatic; C 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 d is independently a -L-CG group, halogen, —OR, —NR 2 , —SR, —CN, —NO 2 , —SO 2 R, —SOR, —SO 2 NR 2 ; —CNO, —NRSO 2 R, —NCO, —N 3 , —SiR 3 ; or an optionally substituted radical selected from the group consisting of C 1-20 aliphatic; C 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 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 d is a -L-CG group;

each L is independently a covalent bond or an optionally substituted, saturated or unsaturated, straight or branched, bivalent C 1-12 hydrocarbon chain, wherein one or more methylene units of L are optionally and independently replaced by -Cy-, —CR 2 —, —NR—, —N(R)C(O)—, —C(O)N(R)—, —N(R)SO 2 —, —SO 2 (R)—, —O—, —C(O)—, —OC(O)—, —OC(O)O—, —C(O)O—, —N(R)C(O)O—, —SiR 2 —, —S—, —SO—, or —SO 2 —;

each CG is independently a cationic bicyclic guanidinium 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 4b is selected from the group consisting of:

where

R c at each occurrence is independently hydrogen, halogen, —OR, —NR 2 , —SR, —CN, —NO 2 , —SO 2 R, —SOR, —SO 2 NR 2 ; —CNO, —NRSO 2 R, —NCO, —N 3 , —SiR 3 ; or an optionally substituted radical selected from the group consisting of C 1-20 aliphatic; C 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 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 1-20 aliphatic; C 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 2 —, —SiR 2 —, —C(═S)—, —C(═NR)—, or —N═N—; a polyether; a C 3 to C 8 substituted or unsubstituted carbocycle; and a C 1 to C 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.

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

4. The metallosalenate complex of claim 3 , wherein the metallosalenate complex is of formula II-aa, II-bb, II-cc, II-dd, II-ee, II-ff, II-gg, or II-hh:

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

6. The metallosalenate complex of claim 2 , wherein M is selected from the group consisting of Cr, Mn, V, Fe, Co, Mo, W, Ru, Al, and Ni.

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

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

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

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

11. The metallosalenate complex of claim 2 , wherein -L- is selected from the group consisting of:

where * represents the site of attachment to the salen ligand, each # represents a site of attachment guanidinium group, and R y is —H, or an optionally substituted radical selected from the group consisting of C 1-6 aliphatic, 3- to 7-membered heterocyclic, phenyl, and 8- to 10-membered aryl.

12. The metallosalenate complex of claim 8 , wherein CG is selected from the group consisting of:

wherein:

R 1 is —S(O)R, —S(O) 2 R, —CO 2 R, —C(O)R, —C(O)NR 2 , —C(O)SR, or R; and

each R is independently an optionally substituted moiety selected from the group consisting of C 1-20 aliphatic; C 1-20 heteroaliphatic; 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.

13. The metallosalenate complex of claim 12 , wherein CG is selected from the group consisting of:

14. The metallosalenate complex of claim 2 , wherein the ligand portion of the metal complex comprises a substructure selected from the group consisting of:

15. The metallosalenate complex of claim 2 , wherein the metal complex is of formula III:

wherein:

R 1 is —S(O)R, —S(O) 2 R, —CO 2 R, —C(O)R, —C(O)NR 2 , —C(O)SR, or R;

each R is independently an optionally substituted moiety selected from the group consisting of C 1-20 aliphatic; C 1-20 heteroaliphatic; 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; and

each X is independently a suitable counterion; 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.

16. The metallosalenate complex of claim 15 , wherein the metal complex is of formula III-a:

17. The metallosalenate complex of claim 15 , wherein R 1 is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, and neohexyl.

18. The metallosalenate complex of claim 17 , wherein R 1 is methyl.

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

20. The metallosalenate complex of claim 19 , wherein Y is chloro, bromo, or iodo.

21. The metallosalenate complex of claim 20 , wherein Y is chloro.

22. The metallosalenate complex of claim 2 , wherein X is selected from the group consisting of —OR x , —O(C═O)R x , —O(C═O)OR x , —O(C═O)N(R x ) 2 , —NC, —CN, —NO 3 , halogen, —N 3 , —O(SO 2 )R x and —OPR x 3 , wherein each R x is, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl and optionally substituted heteroaryl.

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

24. The metallosalenate complex of claim 2 , wherein k is 2.

25. The metallosalenate complex of claim 24 , wherein X is carbonate.

26. The metallosalenate complex of claim 15 , wherein R 1 is methyl, X is carbonate, and k is 2.

27. The metallosalenate complex of claim 2 , wherein M is cobalt.

28. The metallosalenate complex of claim 15 having the structure:

29. A metallosalenate complex comprising a cationic bicyclic guanidinium group, wherein the cationic bicyclic guanidinium group has no free amines, and wherein the guanidinium group is covalently bonded to a polymer.

30. The metallosalenate complex of claim 29 , wherein cationic bicyclic guanidinium group is selected from the group consisting of:

wherein R 1 is a polymer.

31. 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 guanidine-containing portion thereof.

32. 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 isolated polycarbonate polymer composition.

33. The method of claim 32 , wherein the isolated polycarbonate polymer composition is pure.

34. The method of claim 32 , wherein the isolated polycarbonate polymer composition is substantially free of the metal complex or any guanidine-containing portion thereof.

35. 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.