Synthesis, characterisation, and X ray structures of Zn(II) complexes containing bis camphoryldiimine ligands: Application to polymerisation of rac lactide
Abstract Novel Zn(II) complexes, (N1E,N2E) N1,N2 bis(1,7,7 trimethylbicyclo [2.2.1]heptan 2 ylidene)butane 1,2 diamine (BCE) ZnCl2 and (N1E,N3E) 2,2 dimethyl N1,N3 bis(1,7,7 trimethylbicyclo [2.2.1]heptan 2 ylidene)pentane 1,3 diamine (BCP) ZnCl2, were synthesised. X ray diffraction analysis revealed that the geometry around the Zn(II) centre is distorted tetrahedral. The alkoxy derivatives, generated in situ, were highly efficient catalysts for ring opening polymerisation (ROP) of rac lactide (rac LA) yielding polylactide (PLA) with good number average molecular weights and narrow polydispersity indices. (BCP)Zn(OCHMe2)2 exhibited activity for stereoselective ROP of rac LA, and complete conversion occurred within 8 min to attain heterotactic PLA (Pr 0.78)