SINGLE-CRYSTAL ELECTRON-PARAMAGNETIC-RESONANCE OF MATO-S,S')[HYDROTRIS(3,5-DIMETHYLPYRAZOLYL)BORATO] OXOVANADIUM(IV) (ALKYL = ETHYL OR N-PROPYL)

The single-crystal EPR spectra, at room temperature and 0-band frequen cies, of [VO(L)(R2dtc)] diluted in the isostructural molybdenum compou nd are reported [L = hydrotris(3,5-dimethylpyrazolyl)borato, R2dtc = d ialkyldithiocarbamato (R = Et or Pr(n))] . The relative orientations o f the principal axes of the g and A tensors show small angles of non-c oincidence, The relationships between the EPR parameters and the molec ular geometries are considered. Of the eight possible interpretations of the single-crystal data for each compound, those which give the mos t consistent interpretation between the structurally similar molecules are: for R = Et, g11 = 1.958, g22 = 1.983, g33 = 1.986, A11 = -151.9 x 10(-4) CM-1, A22 = -53.0 x 10(-4) cm-1, A33 = -51.0 x 10(-4) CM-1, w ith g11 and A11 at 15.8-degrees and 12.9-degrees from V = O, respectiv ely R = Pr(n), g11 = 1.956, g22 = 1.982, g33 = 1.985, A11 = -153.4 x 1 0(-4) CM-1, A22 = -56.6 x 10(-4) Cm-1, A33 = -48.7 x 10(-4) CM-1, with g11 and A11 at 6.0-degrees and 2.1-degrees from V = O, respectively. These EPR parameters and the molecular geometries, in conjunction with a parametrised angular overlap model, have been used to discuss the e lectronic structures of both molecules. A corresponding treatment of t he literature data on [VO(Et2dtC)2] is also given for comparison.