Synthesis, structure and catalytic activity of phosphine-substituted zirconium salicylaldiminato complexes

Abstract

The reaction of the lithium iminophenolate LiOC 6H 3-2-Bu t -6-CH NAr, where Ar = 3-C 6H 4P{C 6H 3(CF 3) 2-3,5} 2, [Li(O–N P)] with ZrCl 4 affords ZrCl 2(O–N P) 2. Whereas previously reported zirconium bis(salicylaldiminato) complexes are typified by the trans orientation of the O-atoms, the molecular structure ZrCl 2(O–N P) 2 is unusual in adopting an all- cis arrangement of N, O and Cl donors. The crystal structure of the parent ligand, HOC 6H 3-2-Bu t -6-CH NC 6H 4PPh 2-3, is reported for comparison. Upon activation with methylaluminoxane the complex is highly active for the polymerisation of ethylene to oligomers and low-molecular weight polymers. Notably, the catalytic activity is unaffected by the presence of phosphine donors.