Two tetrathiafulvalene salts of a new thiophene-functionalised ferracarborane: electrical conductivity as a function of crystal composition

Two tetrathiafulvalenium (TTF) salts of the new sandwich complex commo-[3,3′-Fe{1-(thiophene-2-yl)-1,2-C2B9H10}2]–, [TTF][Fe(C2B9H10C4H3S)2] and [TTF]5[Fe(C2B9H10C4H3S)2]2, are synthesized; while the 1 : 1 salt is an insulator, the 5 : 2 salt is a semiconductor featuring a conducting superlattice associated with a sublattice that shows ferromagnetic interactions between the ferracarborane complexes; single crystal X-ray studies of the 5 : 2 salt indicate that the electrical conductivity originates from a unique mixed-valence TTF network.