Electron-poor olefin polymerization catalysts based on semi-fluorinated bis(phosphane)s

Two semi-fluorinated bis(phosphane)s, P,P'-(1,2-ethanediyl)-bis[bis(2,4,5-trifluorophenyl)phosphane] (3a), P,P'-(1,2-ethanediyl)bis[bis(2,4-difluorophenyl)phosphane] (3b), and their corresponding Pd(II) and Pt(II)-dichloro complexes (4a,b and 6a,b) have been synthesized. Complexation of P,P'-(1,2-ethanediyl)bis{bis[3,5-di(trifluoromethyl)phenyl]phosphane} (3c) and P,P'-(1,2-ethanediyl)bis[bis(pentafluorophenyl)phosphane] (3d) afforded the related compounds 4c,d and 6c. The Pd(II)-diiodo complexes 5c,d have been obtained from 4c,d by halide exchange with NaI. The solid-state structures of compounds 4b and 5c,d have been determined by single-crystal X-ray diffraction analysis. Activation of 4b-d with MAO produced efficient catalysts for the polymerization of 2-norbornene, which have proved to be superior to the Pd(II)-dichlorides derived from the more electron-rich, structurally related P,P'-(1,2-ethanediyl)bis(diphenylphosphane) (DPPE) or P,P'-(1,3-propanediyl)bis(diphenylphosphane) (DPPP).