Chromium-Lanthanide Multi-Ligand Complexes as Precursors of New Materials

Abstract

Thermochromic properties were found in bimetallic hybrid inorganic-organic complex compounds of hexa (thiocyanate-N) chromates (III) of IIIb-group rare-earth metals and lanthanides complexes with dimethylsulfoxide [M(C2H6SO)8]L, dimethylformamide [M (C3H7NO)8]L, ε-caprolactam [M(εC6H11NO)8]L and nicotinic acid [M(C5H5NCOO)3(H2O)2]L·nH2O, n=1,2, L=[Cr (NCS)6]3-, M=Sc3+, Y3+, Ln3+, obtained by means of direct synthesis from the aqueous solutions, the composition of substances was studied by methods of chemical and electron microscopic analyzes, solubility and chemical resistance were determined. Radiographic and thermogravimetric characteristics, IR spectra, magnetic properties are studied. The experimental data obtained indicate the antiferromagnetic nature of the interaction between paramagnetic centers in the studied ionic compounds, the crystallographic parameters of which were determined by the method of X-ray diffraction analysis of single crystals at low temperatures. In the temperature range of 383-493 K, substances, without changing the physicochemical characteristics, reversibly change color, withstanding many heating-cooling cycles.