Synthesis of π-conjugated organometallic polymer networks

The present paper reports the synthesis of pi-conjugated organometallic polymer networks based on poly[2,5-dioctylocy-1,4-diethynyl-phenylene-alt-2,5,-bis-(2'-ethylhexyloxy)-1,4-phenylene] (EHO-OPPE), a soluble poly(p-phenylene ethynylene) (PPE) derivative. The ethynylene moieties of the polymer coordinate to Pt-0 centers, which act as conjugated cross-links. These materials are readily accessible through ligand-exchange reactions between the linear PPE and Pt(styrene)(3). the in-situ NMR investigation of model reactions of Pt(styrene)(3) with di-phenylacetylene (DPA) has shown that the ethynlene moieties comprised in the PPE readily coordinate to Pt-0 centers under release of the relatively weakly-bound styrene ligands. Spin-coating has resulted in cross-linked films of good optical quality. We also have been able to produce PPE-Pt-gels with high solvent content (>95 wt.-%). As expected, the coordination of Pt markedly influences the photophysical characteristics of the PPE. The photoluminescence is efficiently quenched, and the absorption maximum in the visible regime experiences a hyposochromic shift.