SYNTHESIS AND ELECTRONIC-STRUCTURE OF 1,2-HETEROARYLETHYNES - POTENTIAL MONOMERS FOR LOW BANDGAP CONDUCTIVE POLYMERS

A series of 1,2-heteroarylethynes which are potential monomers to low bandgap materials were synthesized and their He I photoelectron spectr a measured and assigned with the aid of empirical arguments and semi-e mpirical MO calculations. The electronic structure analysis reveals th at C equivalent to C bond is an efficient ''relay'' of pi-electrons an d that it supports inter-ring conjugation. The efficiency depends on t he nature of ring heteroatom, but not on its position within the ring. The importance of C equivalent to C bond relay is discussed in the br oader context of conjugated polymer applications. (C) 1997 Published b y Elsevier Science Ltd.