Mono- and dinuclear oxomolybdenum complexes containing the [TCNQ].- radical anion. Crystal structure of [MoO(Et2NCS2)3]TCNQ.THF, an example of an almost perfectly eclipsed [(TCNQ)2]2- dimer

Abstract : The reactions between TCNQ and the molybdenum (V) dinuclear complexes [Mo2O3(dtc)4] 1a-c (dtc = Et2NCS2 for 1a; Me2NCS2 for 1b; Pr2NCS2 for 1c) afford the molybdenum (VI) mononuclear complexes [MoO(dtc)3]TCNQ 2a-c. 2a can also be obtained from the molybdenum (IV) complex [MoO(dtc)2] 4a by reaction with Et2NC(S)SSC(S)NEt2 and TCNQ or from the molybdenum (VI) complex [MoO(dtc)3]BF4 3a by treatment with LiTCNQ. 2a reacts with TCNQ to give the TCNQ complex salt [MoO(dtc)3](TCNQ)2 5a and with triphenylphosphine to yield the mixed-oxidation state dinuclear complex [Mo2O(dtc)6](TCNQ) 7a; the reaction of 7a with TCNQ gives back 2a. The electrochemical and magnetic properties of these complexes are presented and discussed. The crystal structure of 2a has been determined by X-ray diffraction methods. Least-squares refinement of the structure based on 3489 unique data led to final discrepancy indices of R = 0.025 and Rw = 0.024. The crystal structure consists of [(TCNQ)2]2- anions with an unusual and quasi-perfect eclipsed geometry associated with [MoO(dtc)3]+ cations having a distorted pentagonal bipyramid geometry. © CNRS-Gauthier-Villars.