Chirality and reversible solid state phase transition of a tetranuclear titanium oxido cluster

Abstract

The tetranuclear titanium oxido cluster (μ₄-oxido)-hexakis(μ-thiophene-2-methoxido)-octakis(thiophene-2-methoxido)-tetra-titanium (1), which has been obtained by the reaction of Ti(OiPr)₄ with thiophene-2-methanol in the presence of moisture, consists of a Ti₄(μ₄-O)(μ-O)₆-core and crystallizes as a racemic mixture of two different chiral enantiomers. Compound 1 undergoes a reversible phase transition at 163–168 K in the solid state as evidenced by Powder X-Ray Diffraction (PXRD) and Differential Scanning Calorimetry (DSC). Single-crystal X-ray diffraction studies have been carried out to establish the molecular structure of the high and low temperature phase of 1.