Chromium(III) heterocomplexes—IV Isothiocyanato-complexes of chromium(III) with some monodentate imidazoles

Abstract

Inner complexes of the general formulae, [Cr L 3(NCS) 3] and [Cr L 3(NCS)(OH) 2] ( L = imidazole, and its 1-methyl, 1-ethyl and 1-vinyl derivatives), have been prepared by substitution in K 3[Cr(NCS) 6] and characterised. The 2-alkyl (methyl, ethyl and isopropyl) imidazoles from complexes of the types [Cr L 3(NCS) 3] and [Cr L 2(NCS) 3H 2O] by similar substitutions. The room-temperature magnetic moments (3.64–3.94 B.M.) are characteristic of chromium(III) in octahedral site symmetry. The N-bonding of thiocyanate has been suggested on the basis of v-CN (2130-2105 cm −1), v-CS (865-795 cm −1) and δ-NCS (495-485 cm −1). The electronic spectral bands have been analysed to determine the parameters, 10Dq, B and β, on the bases of which the relative positions of the ligands have been suggested in the spectrochemical and nephelauxetic series.