Abstract
A series of new charge transfer salts of electron donors based on tetrathiafulvalene, TTF, with the anion [Cr(NCS)4(phen)]~ (phen = 1,10-phenanthroline) have been prepared. Single crystal X-ray diffraction provided structures for salts with donors TTF, TMTTF, tetramethyltetrathiafulvalene, and TMTSF, tetramethyltetraselenafulvalene. The salts were found to be [TTF][Cr(NCS)(phen)] at 293 K, [TMTTF][Cr(NCS)(phen)]-CHCl2 at 250 K and rrMTSF][Cr(NCS)(phen)]2-0.5CHCl at 293 K. For the TMTSF compound the solvent is disordered at 293 K so the structure was also solved at 120 K when the solvent becomes ordered. All of the salts have multiple S ⋯S or S ⋯Se close contacts between the anions and cations. The TTF salt is a bulk ferrimagnet with Tc = 9 K and is an insulator whereas the TMTTF salt is an antiferromagnetic (TN = 3.0 K) insulator. Both have close atomic interactions of the phen-donor n-stacking type, but the TMTTF salt also contains close anion-anion contacts and dimerised cations whereas the TTF salt consists of stacks of alternating cations and anions. The TMTSF salt is a paramagnetic semiconductor and does not display n stacking but has close inter-donor Se ⋯Se contacts and isolated anions which afford the magnetic and transport properties. © The Royal Society of Chemistry 2000.