Synthesis, structure and norbornene polymerization behavior of neutral palladium complexes

• DOI: 10.1016/j.poly.2004.03.017
• Publication Date: 2004-04-29T05:50:57Z
• Authors: Hua Liang; Jingyu Liu; Xiaofang Li; Yuesheng Li
• Keywords: Methylaluminoxane; Norbornene; Pyrrole

A series of neutral palladium(II) complexes bearing non-symmetric bidentate pyrrole-iminato or salicylaldiminato chelate ligands have been synthesized, and the structure of representative complexes (3a, 4a, and 5a) have been confirmed by X-ray crystallographic analysis. These palladium complexes have been investigated as catalysts for the polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display high activities and produce vinyl-addition polynorborenes. Catalytic activity of up to 8.52 x 10(3) kg/mol(Pd) h has been observed. Wide-angle X-ray diffraction (WAXD) has been used to investigate the polymer microstructure and it has been found that they are non-crystalline.