Structure and electronic structure of transition metal-containing poly-ynes

Poly-ynes containing sigma-bonded transition metals in the main chain have been synthesised by a novel route. The polymers are soluble in common solvents (e.g. toluene, dichloromethane) thus permitting the production of thin films for evaluation by optical spectroscopy, electron microscopy and conductivity measurements. Results indicate the formation of microcrystalline films, often sufficiently thin for high resolution electron microscopy. Spectroscopic measurements indicate an energy gap of ≈3 eV for the π-π^* bands and the formation of intra-band states by doping or photo-excitation. Evidence for the existence of π-metal hybridisation is presented.