Charge‐Transfer Salts Based on a Dissymmetrical Cyano‐Substituted Tetrathiafulvalene Donor

Abstract

AbstractThree salts of the dissymmetrical TTF derivative cyanobenzene‐ethylenedithio‐tetrathiafulvalene (CNB‐EDT‐TTF) with different anions, namely, (CNB‐EDT‐TTF)2[M(mnt)2] [M = Ni (1), Au (2); mnt = maleonitriledithiolate] and (CNB‐EDT‐TTF)FeBr4 (3) were prepared and characterized by single‐crystal X‐ray diffraction, magnetic susceptibility, and electrical conductivity measurements. Compounds 1 and 2 are isostructural with a crystal structure characterized by segregated chains of side‐by‐side donor dimers and acceptors, and compound 3 presents donors in dimerized stacks. In spite of the different structural types and stoichiometries, all of these compounds have C–N···H pairing interactions associated with R22(10) synthons between donors in nearby chains. All compounds are poor semiconductors, and the magnetic susceptibility of 1 is dominated by the contribution of the paramagnetic [Ni(mnt)2] anions with small antiferromagnetic interactions. The magnetic susceptibility of 3 is dominated by the paramagnetic FeBr4 anions and follows a Curie–Weiss law with a Weiss temperature θ = –19 K, which denotes significant antiferromagnetic interactions that are most likely mediated by the donors.