RADICAL CATION RADICAL ANION SALTS - MOLYBDENUM COMPLEXES CONTAINING THE [TCNQ](CENTER-DOT-) OR [TCNE](CENTER-DOT-) RADICAL-ANIONS - X-RAY CRYSTAL-STRUCTURE OF [MO(ET(2)NCS(2))(4)](TCNQ)

The reactions between the molybdenum(IV) complexes [Mo(dtc)(4)] 1 (dtc = Et(2)NCS(2) for 1a and Me(2)NCS(2) for 1b) and TCNQ produced the 1:1 derivatives [Mo(dtc)(4)](TCNQ) 2. Subsequent reaction of 2 with TCNQ gave the 1:2 complexes 3 [Mo(dtc)(4)](TCNQ)(2). Complexes 1 reacted with TCNE under nitrogen to give the 1:1 compounds [Mo(dtc)(4)](TCNE) 4 while under ambient conditions the pentacyanopropenide derivatives [Mo(dtc)(4)][(NC)(2)C-C(CN)-C(CN)(2)] 5 were obtained. In solution, cyclic voltammetry and ESR studies revealed the presence for all types of complexes of the molybdenum(V) radical cation [Mo(dtc)(4)](.+) which is associated with the radical anion TCNX(.-) in 2 (X = Q) and 4 (X = E) and with a 1:1 mixture of neutral and anionic TCNQ species in 3. Complex 2a has been studied by single crystal X-ray diffraction. The crystal structure consists of monomeric TCNQ(.-) radical anions and [Mo(dtc)(4)](.+) cations with a triangular dodecahedral arrangement of S atoms and a point group symmetry which is approximately D-2d.