Further studies related to the copolymerization of cyclohexene oxide and carbon dioxide catalyzed by chromium Schiff base complexes. Crystal structures of two μ-hydroxo-bridged Schiff base dimers of chromium(III)

Hydroxo-bridged dimers of [(acacen)CrOH]2 (acacen = N,N′-bis(t-butylacetylacetone)-1,2-ethylenediimine) and [(salen)CrOH]2 have been isolated from hydrolysis of the corresponding (acacen)CrCl and (salen)CrOMe derivatives. Structural studies reveal the octahedral coordination around the chromium centers to be distorted. The (acacen)CrCl complex in the presence of cocatalysts PCy3 or [PPN][Cl] is an effective catalyst for the production of polycarbonate from cyclohexene oxide and carbon dioxide, albeit less so than its salen analog.