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.

Graphical abstractHydroxo-bridged dimers of [(acacen)CrOH]2 and [(salen)CrOH]2 have been isolated from hydrolysis of the corresponding (acacen)CrCl and (salen)CrOMe derivatives. X-ray crystallography reveals the octahedral coordination polyhedra around the chromium centers to be distorted. The (acacen)CrCl derivative in the presence of either PCy3 or [PPN][Cl] was shown to be an effective catalyst for the production of completely alternating copolymer from cyclohexene oxide and carbon dioxide.Figure optionsDownload full-size imageDownload as PowerPoint slide