Catalysts

1. A catalyst of formula (I):

wherein:

M 1 and M 2 are independently selected from Zn(II), Cr(II), Co(II), Cu(II), Mn(II), Mg(II), Ni(II), Fe(II), Ti(II), V(II), Cr(III)-X, Co(III)-X, Mn(III)-X, Ni(III)-X, Fe(III)-X, Ca(II), Ge(II), Al(III)-X, Ti(III)-X, V(III)-X, Ge(IV)-(X) 2 or Ti(IV)-(X) 2 ;

wherein at least one of M 1 or M 2 is selected from Ni(II) and Ni(III)-X;

R 1 and R 2 are independently selected from hydrogen, halide, a nitro group, a nitrile group, an imine, an amine, an ether group, a silyl group, a silyl ether group, a sulfoxide group, a sulfonyl group, a sulfinate group or an acetylide group or an optionally substituted alkyl, alkenyl, alkynyl, haloalkyl, aryl, heteroaryl, alkoxy, aryloxy, alkylthio, arylthio, alicyclic or heteroalicyclic group;

R 3 is independently selected from optionally substituted alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene, arylene, heteroarylene or cycloalkylene, wherein alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene and heteroalkynylene, may optionally be interrupted by aryl, heteroaryl, alicyclic or heteroalicyclic;

R 5 is independently selected from H, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl;

E 1 is C, E 2 is O, S or NH or E 1 is N and E 2 is O;

E 3 , E 4 , E 5 and E 6 are selected from N, NR 4 , O and S, wherein when E 3 , E 4 , E 5 or E 6 are N, is , and wherein when E 3 , E 4 , E 5 or E 6 are NR 4 , O or S, is ;

R 4 is independently selected from hydrogen, or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, heteroaryl, alkylheteroaryl or alkylaryl;

X is independently selected from OC(O)R x , OSO 2 R x , OSOR x , OSO(R x ) 2 , S(O)R x , OR x , phosphinate, halide, nitrate, hydroxyl, carbonate, amino, nitro, amido or optionally substituted aliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl or heteroaryl;

R x is independently hydrogen, or optionally substituted aliphatic, haloaliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, alkylaryl or heteroaryl; and

G is absent or independently selected from a neutral or anionic donor ligand which is a Lewis base.

2. The catalyst of claim 1 , wherein at least one of M 1 or M 2 is Ni(II).

3. The catalyst of claim 1 , wherein one of M 1 or M 2 is selected from Ni(II) and Ni(III)-X and the remaining occurrence of M 1 and M 2 is selected from Zn(II), Cr(III)-X, Cr(II), Co(III)-X, Co(II), Cu(II), Mn(III)-X, Mn(II), Mg(II), Ni(II), Ni(III)-X, Fe(II), Fe(III)-X, Ti(II), Ti(III)-X, V(II), V(III)-X, Ge(IV)-(X) 2 and Ti(IV)-(X) 2 .

4. The catalyst of claim 3 , wherein the remaining occurrence of M 1 and M 2 is selected from Zn(II), Cr(III)-X, Co(II), Cu(II), Mn(II), Mg(II), Ni(II), Ni(III)-X, Fe(II), Fe(III)-X and V(II).

5. The catalyst of claim 3 , wherein the remaining occurrence of M 1 and M 2 is selected from Zn(II), Cr(III)-X, Co(II), Mn(II), Mg(II), Ni(II), Ni(III)-X, Fe(II), and Fe(III)-X.

6. The catalyst of claim 3 , wherein the remaining occurrence of M 1 and M 2 is selected from any of: Zn(II), Mg(II), Ni(II), Co(II), Co(III)-X and Ni(III)-X.

7. The catalyst of claim 1 , wherein both M 1 and M 2 are Ni(II).

8. The catalyst of claim 1 , wherein R 3 is selected from substituted or unsubstituted alkylene and substituted or unsubstituted arylene.

9. The catalyst of claim 1 , wherein R 3 is selected from substituted or unsubstituted alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene, arylene, and cycloalkylene.

10. The catalyst of claim 1 , wherein R 3 is selected from 2,2-dimethylpropylenyl, —CH 2 CH 2 CH 2 —, —CH 2 CH(CH 3 )CH 2 —, —CH 2 C(CH 2 C 6 H 5 ) 2 CH 2 —, phenylene, —CH 2 CH 2 —, —CH 2 CH 2 CH 2 CH 2 —. —CH 2 CH 2 N(CH 3 )CH 2 CH 2 —, 1,4-cyclohexandiyl, —CH 2 CH 2 CH (C 2 H 5 )— or —CH 2 C(C 2 H 5 ) 2 CH 2 —.

11. The catalyst of claim 1 , wherein R 3 is selected from is selected from 2,2-dimethylpropylenyl, —CH 2 CH 2 CH 2 , —CH 2 CH(CH 3 )CH 2 —, —CH 2 C(Ch 2 C 6 H 5 ) 2 CH 2 —, —CH 2 CH 2 CH(C 2 H 5 )—, or —CH 2 CH 2 CH 2 CH 2 —.

12. The catalyst of claim 1 , wherein R 3 is selected from a 2,2-dimethylpropylenyl, —CH 2 C(CH 2 C 6 H 5 ) 2 CH 2 —, —CH 2 C(C 2 H 5 ) 2 CH 2 — and —CH 2 CH 2 CH (C 2 H 5 )—.

13. The catalyst of claim 1 , wherein R 3 is a 2,2-dialkylpropylenyl.

14. The catalyst of claim 1 , wherein both occurrences of R 3 are the same.

15. The catalyst of claim 1 , wherein E 1 is C and E 2 is O, S, or NH.

16. The catalyst of claim 1 , wherein E 3 , E 4 , E 5 and E 6 are NR 4 .

17. The catalyst of claim 1 , wherein R 4 is selected from hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, aryl or heteroaryl.

18. The catalyst of claim 1 , wherein each occurrence of R 4 is the same.

19. The catalyst of claim 1 , wherein E 3 , E 4 , E 5 and E 6 are the same.

20. The catalyst of claim 1 , wherein R 1 is selected from hydrogen, halide, amino, nitro, sulfoxide, sulfonyl, sulfinate, silyl, silyl ether, and optionally substituted alkyl, alkenyl, aryl, heteroaryl, alkoxy, aryloxy, arylthio or alkylthio.

21. The catalyst of claim 1 , wherein R 1 is selected from halide, sulfoxide, silyl, and an optionally substituted alkyl, heteroaryl or alkoxy.

22. The catalyst of claim 1 , wherein R 1 is selected from t-butyl, methoxy, triethylsilyl, bromide, SO 2 CH 3 , or piperidinyl.

23. The catalyst of claim 22 , wherein R 1 is selected from t-butyl or triethylsilyl.

24. The catalyst of claim 1 , wherein both occurrences of R 1 are the same.

25. The catalyst of claim 1 , wherein X is selected from OC(O)R x , OSO 2 R x , OS(O)R x , OSO(R x ) 2 , S(O)R x , OR x , phosphinate, halide, nitrate, hydroxyl, carbonate, amino, nitro, amido, and optionally substituted alkyl, heteroalkyl, alicyclic, heteroalicyclic, aryl or heteroaryl.

26. The catalyst of claim 1 , wherein X is selected from OC(O)R x , OR x , halide, carbonate, amino, nitro, alkyl, aryl, heteroaryl, phosphinate or OSO 2 R x .

27. The catalyst of claim 1 , wherein X is selected from OC(O)R x , OR x , halide, alkyl, aryl, heteroaryl, phosphinate or OSO 2 R x .

28. The catalyst of claim 1 , wherein X is OC(O)R x .

29. The catalyst of claim 1 , wherein X is selected from OAc, O 2 CCF 3 , or O 2 C(CH 2 ) 3 Cy.

30. The catalyst of claim 1 , wherein both occurrences of X are the same.

31. The catalyst of claim 1 , wherein R x is an optionally substituted alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, cycloalkyl or alkylaryl.

32. The catalyst of claim 1 , wherein R x is selected from hydrogen, or an optionally substituted aliphatic, haloaliphatic, heteroaliphatic, alicyclic, heteroalicyclic, aryl, alkylaryl or heteroaryl.

33. The catalyst of claim 1 , wherein R x is selected from an optionally substituted alkyl, alkenyl, heteroalkyl, or cycloalkyl.

34. The catalyst of claim 1 , wherein R x is selected from an optionally substituted alkyl, heteroalkyl, or cycloalkyl.

35. The catalyst of claim 1 , wherein R x is an optionally substituted alkyl.

36. The catalyst of claim 1 , wherein both occurrences of R x are the same.

37. The catalyst of claim 1 , wherein each occurrence of R 2 and R 5 is hydrogen.

38. The catalyst of claim 1 , wherein both occurrences of R 1 are the same, and are selected from hydrogen, halide, amino, nitro, sulfoxide, sulfonyl, sulfinate, silyl, silyl ether and an optionally substituted alkyl, alkenyl, aryl, heteroaryl, alkoxy, aryloxy or alkylthio;

R 2 is hydrogen;

both occurrences of R 3 are the same, and are selected from substituted or unsubstituted alkylene and substituted or unsubstituted arylene;

E 1 is C and E 2 is O;

E 3 , E 4 , E 5 and E 6 are NR 4 ;

R 4 is hydrogen;

each X is the same, and is selected from OC(O)R x , OR x , halide, carbonate, amino, nitro, alkyl, aryl, heteroaryl, phosphinate or OSO 2 R x , each R x is the same and is selected from alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl or alkylaryl;

each G, where present, is the same and is selected from halide; water; a heteroaryl optionally substituted by alkyl, alkenyl, alkynyl, alkoxy, halogen, hydroxyl, nitro or nitrile; and

one of M 1 and M 2 is Ni(II) or Ni(III)-X, and the remaining M 1 or M 2 is selected from Mg(II), Zn(II), Cr(III)-X, Co(II), Co(III)-X Mn(II), Ni(II), Ni(III)-X, Fe(II), and Fe(III)-X.

39. The catalyst of claim 38 , wherein both occurrences of M 1 and M 2 are selected from Ni(II) and Ni(III)-X.

40. The catalyst of claim 38 , wherein R 1 is hydrogen, halide, silyl, silyl ether, sulfonyl or optionally substituted alkyl or alkoxyl.

41. The catalyst of claim 1 , of the formula (lb):

wherein:

both occurrences of R 1 are the same, and are selected from hydrogen, halide, amino, nitro, sulfoxide, sulfonyl, sulfinate, silyl, silyl ether and an optionally substituted alkyl, alkenyl, aryl, heteroaryl, alkoxy, aryloxy or alkylthio;

R 3 is selected from substituted or unsubstituted alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene or heteroalkynylene, cycloalkylene or arylene;

each X is the same, and is selected from OC(O)R x , OR x , halide, carbonate, amino, nitro, alkyl, aryl, heteroaryl, phosphinate or OSO 2 R x , R x is alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl or alkylaryl;

R x is alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl or alkylaryl;

each G, where present, is independently selected from halide; water; a heteroaryl optionally substituted by alkyl, alkenyl, alkynyl, alkoxy, halogen, hydroxyl, nitro or nitrile; and

one occurrence of M 1 and M 2 is Ni(II) or Ni(III)-X, and the remaining occurrence of M 1 or M 2 is selected from Mg(II), Zn(II), Cr(III)-X, Co(II),

Co(III)-X, Mn(II), Ni(II), Ni(III)-X, Fe(II), and Fe(III)-X.

42. The catalyst of claim 41 , wherein R 1 is hydrogen, halide, silyl, silyl ether, sulfonyl, and optionally substituted alkyl or alkoxy.

43. The catalyst of claim 41 , wherein R 3 is selected from propylenyl, 2,2-dimethylpropylenyl, and substituted or unsubstituted phenylenyl or biphenylenyl.

44. The catalyst of claim 41 , wherein M 1 and M 2 are selected from Ni(II) and Ni(III)-X.

45. The catalyst of claim 41 , wherein X is OC(O)R x , OR x , halide, alkyl, aryl, heteroaryl, phosphinate or OSO 2 R x .

46. The catalyst of claim 41 , wherein R x is alkyl, alkenyl, alkynyl, heteroalkyl, aryl, heteroaryl, or alkylaryl.

47. The catalyst of claim 41 , wherein G is absent.

48. The catalyst of claim 1 of the formula:

49. A process for the reaction of:

a. carbon dioxide with an epoxide;

b. an epoxide and an anhydride; and/or

c. a lactide and/or a lactone, in the presence of the catalyst of claim 1 .

50. The process of claim 49 , wherein the epoxide is ethylene oxide, butylene oxide, propylene oxide or cyclohexene oxide.