The reaction between Pt- and Pd-cis di-chloro complexes and 4,4 '-diethynylbiphenyl: synthesis and characterisation of a 'zigzag' metal/poly-yne polymer

The synthesis of poly-yne polymers containing transition metals inserted in the main chain has been attempted by reacting a dialkyne molecule, 4,4'-di ethynylbiphenyl (or DEBP), with [PtCl2(dppe)] and [PdCl2(dppe)], the platin um- and palladium-cis square-planar dichlorine complexes containing dipheny lphosphine ethane (dppe) as bidentate ligand. The aim of this work was to o btain organometallic polymers ([Pt(dppe)DEBP](n) and [Pd(dppe)DEBP](n), res pectively) having an all-cis 'zigzag' structure, by formation of a sigma -a cetylide bond between the transition metal complexes and the dialkyne molec ule. When [PtCl2(dppe)] was reacted with DEBP, the formation of a chlorine- terminated [Pt(dppe)DEBP], oligomer was evidenced in the reaction involving the Pd(II) complex, on the other hand, [PdCl2(dppe)] seems to catalyse the polymerisation of DEBP via opening of the triple bond, producing a poly-DE BP polymer containing Pd(II) atoms inserted in the main chain. (C) 2001 Els evier Science Ltd. All rights reserved.