SYNTHESIS, STRUCTURE AND SPECTRA OF AMMONIUM (SALICYLALDEHYDES<i>S</i>-METHYLTIOSEMIC ARBAZONATO) DIOXOVANADATE(V) MONOHYDRATE

Abstract

Abstract Crystals of ammonium (salicylaldehyde S-methylthiosemicarbazonato)dioxovanadate(V)monohydrate, NH4[VO2L]·H2O were synthesized from ammonia–ethanol solution of VCl3 and salicylaldehyde S-methylthiosemicarbazone (H2L). They belong to the monocyclic system, space group P21/c, a, = 5.864(2), b = 16.382(7), c = 13.931(5)Å, β = 97.60(3)°, Dm = 1.62, Dc = 1.63. The position of the vanadium atom was determined on the basis of the distribution of Patterson function, coordinates of the other atoms on the basis of Fourier synthesis. Vanadium occurs in the complex within the VO2 + group, lacking d-electrons. The coordination polyhedron has the form of a deformed square pyramid. The bands in infrared spectrum indicate the existence of valence oscillations of O=V=O group. Absorption spectra of the complex and ligand were calculated from the measured reflectance spectra by the application of Kubelka-Munk theory. Two out of the seven absorption maxima in the spectrum, result from intraligand transitions and the others are most likely related to the transitions involving charge transfer from the ligand π and n orbitals to vacant d orbitals of vanadium.