Complexation of unsaturated carbon-carbon bonds in pi-conjugated polymers with transition metals

The present paper explores the possibility of preparing pi -conjugated orga nometallic polymer hybrid systems based on a poly(p-phenylene ethynylene) ( PPE) derivative, in which the ethynylene moieties of the polymer are coordi nated to platinum(II) centers. The use of the "bifunctional" [Pt-Cu-(Cl)Cl( PhCH=CH2)](2) (2) allows, under appropriate conditions, the formation of th ree-dimensionally cross-linked, conjugated PPE-platinum(II) networks. The s ynthesis of [Pt-(mu -Cl)Cl(PhC equivalent to CPh)](2),as a model compound, and a series of model reactions of 2 with diphenylacetylene (3) have enable d an NMR study which has revealed a number of equilibria, and suggests a mi xed Pt-styrene-acetylene complex as a key structure. As expected, the coord ination of Pt markedly influences the photophysical characteristics of the PPE. The photoluminescence is efficiently quenched, and the absorption maxi mum in the visible regime experiences a hypsochromic shift upon complexatio n with 2.