Polydiacetylenes and analogies to inorganic semiconductors and graphite

Abstract The crystallography and one-dimensional electronic structure of polydiacetylenes (PDAs) stimulate a variety of chemical and physical studies. 13 C CP-MAS n.m.r. studies of the PDAs from PTS and TCDU as well as 1, 1, 4,-4-tetraphenylbutatriene establish the en-yne bond representation for TCDU and rule out a significant contribution from a butatriene form to the ground state at room temperature. The current status of third-order non-linear optical phenomena in PDAs and the conversion of PDAs to conductive materials by ion implantation is presented. Our anisotropic chemical modification of poly-DCH is conceptually distinguished from the usual charge transfer doping of non-crystalline polymers.