abstract
Two new families of charge transfer solids based on transition metal bis-maleonitrile dithiolate complexes [M(mnt)(2)](n-) and two tetrathiatulvalene (TTF) derivatives containing external sulfur atoms have been synthesized and characterized as (BMDT-TTF)(2)[M(mnt)(2)] and (EDT-TTF)[M(mnt)(2)], where BMDT-TTF stands for bis(methylenedithio)-tetrathiafulvalene, EDT-TTF for ethylenedithio-tetrathiafulvalene and M = Au, Pt and Ni. The salts of the series (BMDT-TTF)(2)[M(mnt)(2)] are quasi-isostructural and crystallize forming mixed ADDA stacks along a + b. In the (BMDT-TTF)(2)[Au(Mnt)(2)] salt, the anion complex is diamagnetic and has a formal charge of -1, whereas in Ni salt the anion has a charge of -2, being also diamagnetic. The magnetic properties of the An salt follow a ID antiferromagnetic Heisenberg model modified with a molecular field. The salt with Ni displays very strong antiferromagnetic interactions. The (EDT-TTF)[M(mnt)(2)] salts with M = Ni and Pt are isostructural and crystallize forming alternated DADA stacks. The anions, with a formal charge of -1, are paramagnetic with a spin 1 Their magnetic susceptibility can be successfully simulated within the antiferromagnetic uniform chain model of Heisenberg. Lastly, (EDT-TTF)[Au(mnt)(2)] crystallizes in the triclinic space group P(-1) forming also alternated stacks along c in which the EDT-TTF molecules are 50% disordered. (C) 2002 Elsevier Science (USA).
keywords
CRYSTAL-STRUCTURE; MOLECULAR CONDUCTORS; COMPLEXES; SALTS; METALS; (PER)2M(MNT)2; THERMOPOWER; LIGAND; LADDER
subject category
Chemistry
authors
Mas-Torrent, M; Alves, H; Lopes, EB; Almeida, M; Wurst, K; Vidal-Gancedo, J; Veciana, J; Rovira, C