MONONUCLEAR AND DINUCLEAR OXOMOLYBDENUM COMPLEXES CONTAINING THE [TCNQ](.-) RADICAL-ANION - CRYSTAL-STRUCTURE OF [MOO(ET(2)NCS(2))(3)]TCNQ-CENTER-DOT-THF, AN EXAMPLE OF AN ALMOST PERFECTLY ECLIPSED [(TCNQ)(2)](2-) DIMER

The reactions between TCNQ and the molybdenum (V) dinuclear complexes [Mo2O3(dtc)(4)] 1a-c (dtc = Et(2)NCS(2) for la; Me(2)NCS(2) for 1b; Pr 2NCS2 for 1c) afford the molybdenum (VI) mononuclear complexes [MoO(dt c)(3)]TCNQ 2a-c. 2a can also be obtained from the molybdenum (IV) comp lex [MoO(dtc)(2)] 4a by reaction with Et(2)NC(S)SSC(S)NEt(2) and TCNQ or from the molybdenum (VI) complex [MoO(dtc)(3)]BF4 3a by treatment w ith LiTCNQ. 2a reacts with TCNQ to give the TCNQ complex salt [MoO(dtc )(3)](TCNQ)(2) 5a and with triphenylphosphine to yield the mixed-oxida tion state dinuclear complex [Mo2O(dtc)(6)](TCNQ) 7a; the reaction of 7a with TCNQ gives back 2a. The electrochemical and magnetic propertie s of these complexes are presented and discussed. The crystal structur e of 2a has been determined by X-ray diffraction methods. Least-square s refinement of the structure based on 3489 unique data led to final d iscrepancy indices of R = 0.025 and R(W) = 0.024. The crystal structur e consists of [(TCNQ)(2)](2-) anions with an unusual and quasi-perfect eclipsed geometry associated with [MoO(dtc)(3)](+) cations having a d istorted pentagonal bipyramid geometry.