Synthesis, structural and spectral investigations of new types of dioxovanadium(V) complexes withS-methylthiosemicarbazones derived from salicyl and 2,4-dihydroxybenzaldehydes. X-ray structure of ammonium(salicylaldehydeS-methylthiosemicarbazonato) dioxovanadate(V) monohydrate

Summary

The x-ray crystal structure of [VO₂(HL¹)] (where L¹ denotes the dianion of theS-methylthiosemicarbazone of salicylaldehyde) has been determined and refined to R=0.058 (R_w=0.063) for 3377 observed reflections.

There are two symmetrically independent molecules in the asymmetric unit, showing no significant differences in their geometries. The vanadium atom is pentacoordinated in a distorted square-pyramidal arrangement.

Absorption spectra of [VO₂(HL¹)] and [VO₂(HL²)], in the 10000–45000 cm⁻¹ range, were calculated from the measured reflectance spectra, applying Kubelka-Munk's theory. The extinction coefficients were determined from the absorption spectra of the solutions of these complexes in methanol. The observed maxima are interpreted on the basis of intraligand transition and charge-transfer spectra on the basis of the presence of approximate groupC _2v for both complexes.