Highly distorted octahedral molybdenum(II) complexes: Synthesis, crystal structure, and properties of [Mo(S2C6H4)(CO)2(PMenPh3-n)2](n=0-3)

Four hexacoordinated molybdenum complexes, [Mo(S2C6H4)(CO)2(PMenPh3-n)(2)] (n = 0 (1), 1 (2), 2 (3), 3 (4)), were synthesized via the one-pot reaction of [Mo(eta(3)-C3H5)(Br)(CH3CN)(2)(CO)(2)], 1,2-H(2)bdt (bdt = benzenedithiolate), and phosphines. The structure of all complexes was successfully characterized by single crystal X-ray diffraction. For the stabilization these complexes, the bdt ligand and the axial phosphine ligands are not located on the ideal vertexes of octahedron in order to reduce the destabilizing overlapping of molecular orbitals. Therefore, six-coordinated complexes generally adopt an octahedral geometry, the complexes 1-4 showed structures intermediate between a distorted octahedron and a regular trigonal prism, i.e. configurations far from the ideal octahedral geometry. All complexes underwent a two-step 2e(-) reduction reaction, with the reduction potential of the Mo center shifting towards negative values moving from compound 1 to compound 4. (C) 2016 Elsevier Ltd. All rights reserved.