Crystal structures of the first diselenophosphinate molybdenum(II) allyl complexes: [Mo(CH3CN)(κ3-C3H5)](CO)2(κ2-Se2PPh2)] and [Mo(κ3-C3H5)(CO)2(κ2-Phen)(κ1-Se2PPh2)]

A reaction of [Mo(CH3CN)2(κ3-C3H5)(CO)2(Br)] (complex 1) and (Et4N)[Se2PPh2] (complex 2) produces a κ2-diselenophosphinate molybdenum [Mo(CH3CN)(κ3-C3H5)(CO)2(κ2-Se2PPh2)] complex (complex 3). Treatment of 3 with 1,10-phenanthroline, C12H8N2, yields a κ1-diseleno­phosphinate [Mo(κ3-C3H5)(CO)2(κ2-Phen)(κ1-Se2PPh2)] complex (complex 4). The coordination geometry around the molybdenum atom of complexes 3 and 4 is octahedral with aceto­nitrile, allyl, two carbonyls, and two selenium atoms and allyl, two carbonyls, two nitrogen atoms of the 1,10-phenanthroline ligand, and one selenium atom, occupying six-coordination sites, respectively. To the best of our knowledge, complexes 3 and 4 are the first diselenophosphinate molybdenum allyl complexes. Complexes 3 and 4 are characterized through the elemental analysis, fast atom bombardment mass spectrometry, 31P NMR spectroscopy, and single crystal X-ray diffraction.