Synthesis and structure of a new dinuclear oxomolybdate complex containing a linear OMoOMoO unit

Abstract A new dinuclear oxomolybdate complex [(C 6 H 4 OCHN(CH 2 ) 3 NHCOC 6 H 4 ) 2 Mo 2 O 3 ]·2H 2 O was obtained as black needle crystals by the reaction of MoCl 3 ·3H 2 O with a specially designed tetradentate Schiff base ligand under solvothermal conditions. Single-crystal X-ray diffraction analysis indicates that it crystallizes in a monoclinic P 2 1 / c space group with a rare oxo-bridged dinuclear molybdenum structure. The structure is characterized by two MoO 4 N 2 octahedra sharing a corner oxygen atom in a completely linear MoOMo arrangement. In addition to being the first example of nearly linear OMoOMoO arrangements, the present structure features a MoO single bond at two ends, in sharp contrast with the known OMOMO (M=W, Re) units that contain MO double bonds for terminal oxygen, due to the spatial chelating requirement of the long tetradentate Schiff base ligand. The completely linear MoOMo structure together with the relatively short MoO distance of 1.8819(7) A suggests the involvement of metal–oxygen π bonding.