Patent ID: 6870004

Claim:
A method of using a metal-ligand complex to prepare a polycarbonate compound having a low polydispersity index, said method comprising: providing an epoxide substrate; admixing a metal-ligand complex with said substrate, said complex having the structural formula wherein R′, R″, R 2 , and R 2 ′ are independently selected from the group consisting of hydrogen, methyl, alkyl, substituted alkyl, phenyl, aryl, substituted phenyl, substituted aryl; wherein L is a linker moiety (CR 5 R 6 ) n where n=0-4 and R 5 and R 6 are selected from the group consisting of hydrogen, methyl, alkyl, substituted alkyl, phenyl, aryl, substituted phenyl, substituted aryl and combinations of said moieties; wherein A and B are ligands selected from the group consisting of neutral ligands, anionic ligands and a combination thereof, said selection determined by the oxidation state of M, and wherein A and B are optionally present, and A and B are independently selected from the group consisting of Cl, OAc, NO 3 , p-CH 3 SO 3 , BF 4 , O 4 Cl, CF 3 SO 3 , SbF 6 , and a combination thereof, and wherein M is a metal selected from the group consisting of Co, Cr, Fe, Ni, Ti, Cu, Zn, Sn and Al. wherein R 3 is selected from the group consisting of hydrogen, alkyl, substituted alkyl, phenyl, aryl, substituted phenyl, substituted aryl, alkoxy, halide and nitro moieties; and wherein R 4 is selected from the group consisting of hydrogen, alkyl, substituted alkyl, phenyl, aryl, substituted phenyl, substituted aryl, alkoxy, halide, and nitro moieties, introducing gaseous carbon dioxide to said substrate and complex admixture; and isolating a polycarbonate composition as the reaction product of said substrate and carbon dioxide.