A Methyl Substituted Thiophenic-TTF Donor and its Salts

α-Methyldithiophene–tetrathiafulvalene (α-mDT-TTF), the first alkyl-substituted thiophene–tetrathiafulvalene electronic donor, and some of its charge-transfer salts were explored. The crystal structure of α-mDT-TTF is composed of molecular stacks aligned parallel to each other. Its cyclic voltammetry shows higher electron-donor ability than the unsubstituted analogue. This material was employed as a semiconductor in an organic field-effect transistor and showed a mobility of 4 10–4 cm2V–1 s–1. Two charge-transfer salts of this donor with [M(mnt)2]– anions (mnt = maleonitriledithiolate), M = Co and Au, were obtained by electrocrystallization; they present unusual stoichiometries: (α-mDTTTF)[ Co(mnt)2] and (α-mDT-TTF)3[Au(mnt)2]2. In the cobalt compound, the donor molecules are fully oxidized and the Co complex is dimerized; it presents semiconducting behavior (7 10–3 Scm–1). The gold compound is composed of alternating stacks of donor trimers and pairs of anions.This work was supported by Portuguese Fundação do Ministério de Ciência e Tecnologia (FCT) through contract PTDC/QEQ-SUP/ 1413/2012, UID/Multi/04349/2013, RECI/QEQ-QIN/0189/2012 and PhD grant SFRH/BD/86131/2012.We also acknowledge financial support of the European Union (EU) project ERC StG 2012- 306826 e-GAMES and the Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), the Spanish Ministerio de Ciencia e Innovación (MICINN), and Fondos Europeos para el Desarrollo Regional (FEDER) with project BE-WELL CTQ2013-40480-R and the Generalitat de Catalunya with project 2014-SGR. We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities, and we would like to thank Jonathan Wright for assistance in using beamline ID11. [Peer reviewe