Structure and thermal behavior of two bimetallic carboxylates: Cs[M(CCl3COO)3(H2O)3], M = Co, Ni

Abstract

Bimetallic trichloroacetates of the composition Cs[M(CCl3COO)3(H2O)3], where (I: M = Co, II: Ni) were synthesized. The structures of these compounds have been determined by the single crystal X-ray diffraction. The compounds are isostructural and crystallize in the trigonal system, sp.gr. $$ R\overline{3} $$ . а = b = 10.5770(6), c = 32.8213(2) A, α = β = 90°, γ = 120°, Z = 6, V = 3179.9(4) A3 (for Со compound), а = b = 10.5404(4), c = 32.7116(7) A, α = β = 90°, γ = 120°, Z = 6, V = 3147.4(2) A3 (for Ni compound). The structure contains [M(CCl3COO)3(H2O)3] anions, where (M = Co, Ni). The d-metal atom is located in the distorted octahedral environment of oxygen atoms in the anion. These compounds have nearly the same IR spectra. The thermal stability of the compounds was studied. The thermal behavior of these compounds is similar to each other, but the difference is in the stage of loss of crystallization water—for the nickel compound, this process starts at 20 °C higher than for the cobalt compound. The high-temperature process of the transition of metal chlorides to the gas phase differs: for the cobalt compound, the mass loss begins at 600 °C, whereas for the nickel compound, the mass loss begins at 720 °C. The compounds obtained are the first examples of alkaline metal—transition metal trichloroacetates.