Synthesis Electrochemistry Geometric and Electronic Structure of Oxo-Molybdenum Compounds Involved in an Oxygen Atom Transferring System

摘要

The oxygen atom transfer reactivity of Tp*MoO2(SPh) (>1) (where Tp* = hydrotris-(3,5-dimethylpyrazol-1-yl)borate) with trimethyl phosphine (PMe3) has been investigated. The reaction proceed through a diamagnetic phosphoryl intermediate complex, Tp*MoO(SPh)(OPMe3) (>2), which has been isolated and characterized by IR, NMR, UV-visible spectroscopy, and mass spectrometry. The molecular structure of >2 has been determined by X-ray crystallography. The complex crystallizes in monoclinic (P21) space group, a = 19.81 (1) Å, b = 11.1 (4) Å, c = 18.416 (5) Å, β= 121.2 (3)°, V = 3463.8(25) ų with Z = 4. In acetonitrile, complex >2 exchanges its phosphoryl ligand with a solvent molecule resulting in Tp*MoO(SPh)(MeCN) (>3), which has been isolated and also characterized spectroscopically and by X-ray crystallography. Compound >3 crystallizes in triclinic (P-1) space group, a = 10.159 (6) Å, b = 18.563 (5) Å, c = 7.986 (3) Å, α = 96.22(3)°, β = 121.2 (3)°, γ = 84.64(3)°, V = 1452.4(11) ų with Z = 2. The electronic structures of the complexes have been investigated by density functional theory and the redox chemistry has been investigated by cyclic and differential pulse voltammetry. In acetonitrile, complex >2 spontaneously transforms to complex, >3 at a rate of 5.6 × 10⁻⁴ s⁻¹.