DIOXOMOLYBDENUM(VI) COMPLEXES OF TRIPODAL NITROGEN-DONOR LIGANDS - SYNTHESES AND SPECTROSCOPIC, STRUCTURAL, AND ELECTROCHEMICAL STUDIES, INCLUDING THE GENERATION OF EPR-ACTIVE MOLYBDENUM(V) SPECIES IN SOLUTION

Abstract

The dioxo-Mo(VI) complexes LM0O2X [L = hydrotris(3,5-dimethylpyrazol-l-yl) borate (La), hydrotris(3-isopropylpyrazol-l-yl) borate (Lb), hydrotris(3,5-dimethyl-l,2,4-triazol-1-yl) borate (Lc); X = Cl, Br, NCS, OMe, OEt, OPh, SPri, SPh, SCH2Ph] have been synthesized and characterized by spectroscopic and structural methods. The infrared spectra of the complexes exhibit v(MoO2) bands at 940−920 and 910−890 cm−1, and the 1H NMR spectra are indicative of molecular Cs symmetry in solution. The X-ray crystal structures of three complexes are reported. LaMoO2(SPh) : monoclinic space group P21/c, a = 18.265(6) Å,b = 8.110(3) Å, c = 18.299(3) Å, β = 117.06(2) °, V = 2414(1) Å3 with Z = 4. LbMoO2(OMe) ..