Nuclear Quadrupole Perturbations in 51V NMR Spectra of Oxovanadium(+V) Complexes

Abstract

Abstract Nuclear electric quadrupole coupling constants e2qQ/h have been obtained by evaluation of quadrupole perturbations in 51V NMR spectra of various vanadyl esters and esterchlorides of the general formula VOCl3-n(OR)n (n=0-3; R = Me, Prn , Prn, Bun and Bui). e2qQ/h values have been calculated from (i) 2nd. order quadrupole splittings of the 51V NMR signals in pseudo-polycrastalline samples, (ii) 1st. order quadrupole splittings in nematic liquid crystals and (iii) line widths A ⊿ν1/2 of the 51V and 35Cl NMR signals in the liquid isotropic state and e2qQ/h(35Cl) obtained by pure NQR measurements. The influences of the asymmetry parameter η and the orientation of the crystallites in powder spectra are considered, and temperature and concentration effects upon ⊿ν1/2 and 51V shielding (isotropic phases) and the ordering factor Sa (meso-phases) are discussed.