New Insights into the Berg−Holm Oxomolybdoenzyme Model

Abstract

Reaction of MoO2(L-NS2) [L-NS2 = 2,6-bis(2,2-diphenyl-2-thioethyl)pyridinate(2−)] with PPh3 in N,N-dimethylformamide (dmf), chloroform, or mixtures thereof results in the formation of purple, dinuclear, μ-oxo-Mo(V) compounds, Mo2O3(L-NS2)2·2sol (sol = dmf, CHCl3, or mixtures thereof), which can be dried at 80 °C under vacuum to give Mo2O3(L-NS2)2. 31P NMR experiments were consistent with the following reaction: 2MoVIO2(L-NS2) + PPh3 → MoV2O3(L-NS2)2 + OPPh3. The compounds have been characterized by microanalysis, IR, and UV−visible spectroscopy, electrospray ionization mass spectrometry, and X-ray diffraction studies of Mo2O3(L-NS2)2·2dmf and Mo2O3(L-NS2)2·2CHCl3. Dinuclear Mo2O3(L-NS2)2 is comprised of five-coordinate, trigonal-bipyramidal Mo centers bridged by a strictly linear Mo−O−Mo unit with Mo−O = 1.8639(6) A for the dmf disolvate [1.8703(4) A for the CHCl3 disolvate]. Each Mo center is further coordinated by a tridentate L-NS2 ligand and a terminal oxo ligand (MoO = 1.681(5) A [1.696(4) A]). The ...