2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (TTP) derivatives having four long alkylthio chains

pi-Electron donors having four long alkylthio chains, TTCn- TTP (2,5-bis[4,5-bis(alkylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene; n=2-5; 1a-d) have been synthesized. Crystals consisting of the neutral donors show moderately low resistivities (6x10(3)-6x10(7) Omega cm). Origins of the low resistivities are investigated by X-ray analyses; TTC3-TTP (1b) displays so-called theta-type donor arrangement in contrast to TTC4-TTP (1c) with uniform-stacked one, both of which indicate fastener effect. (C) 2002 Elsevier Science Ltd. All rights reserved.