Synthesis, photophysics and pyrolytic ceramization of a platinum(II)-containing poly(germylacetylene) polymer

A synthetic route to a new polymeric platinum(II)-containing germylacetylene has been developed. Soluble and thermally stable platinum(II) polyyne polymer trans-[–Pt(PBu3)2Ctriple bond; length of mdashCGePh2Ctriple bond; length of mdashC–]n (P1) was prepared in good yield by CuI-catalyzed polymerization of trans-[Pt(PBu3)2Cl2] and Ph2Ge(Ctriple bond; length of mdashCH)2. We report the optical absorption and photoluminescence spectra of P1 and the results are compared with platinum(II) polyynes with purely acetylenic and other (hetero)aromatic conjugated units. Harvesting of organic triplet emission harnessed through the strong heavy-atom effect of Pt and Ge was examined. Polymer P1 was found to have a high optical bandgap (ca. 3.84 eV). The influence of metal and sp3-hybridized germyl-based conjugation interrupter on the intersystem crossing rate and the spatial extent of the lowest singlet and triplet excitons were fully elucidated. Our investigations indicate that a high-bandgap polymer P intrinsically gives rise to a very efficient phosphorescence with fast radiative decay. Remarkably, a simple single-step method was also established for the synthesis of platinum–germanium (PtGe) alloy nanoparticles using P1 as the polymer precursor and the resulting ceramic metal alloys have been characterized by powder X-ray diffraction, energy dispersive X-ray analysis and transmission electron microscopy.