GREEN AND ORANGE CRYSTALLINE FORMS OF [VO(N-SALICYLIDENE-N'-3-ETHOXYSALICYLIDENE-(R,R)-1,2-CYCLOHEXANEDIAMINE)], SEPARATION OF THE DIASTEREOMERIC PAIR, AND ISOMERIZATION BETWEEN THEM IN THE SOLID-STATE

A pair of diastereomers, I and II, of the titled complex were separated by liquid chromatography, and each of them crystallized in two different colors, green and orange. I(green) and II(green) were assigned to a mononuclear square pyramidal structure, while I(orange) and II(orange) to a polynuclear linear chain structure. The orange complexes turned green by heating at 195 degrees C in a few minutes. All of the four complexes undergo isomerization at 195 degrees C in the solid state to give an equilibrium mixture, I:II approximate to 1:1.