Phase transformations in<i>t</i>-butylcalix[4]arene inclusion compounds at elevated temperatures

Abstract

Cl2[C16H12Cl2]2 Te(IV)(1) and Br2[C16H12Br2]2 Te(IV) (2). In both compounds the primary geometry about the Te(IV) atom is disphenoidal, with the halides in the apical positions and the lone pair of electrons and C atoms in the equatorial plane. In (1), the Te(IV) atom participates in a -C6H5 interaction with one of the peripheric phenyl rings of a neighbouring molecule (Te ... centroid = 3.757 ), resulting in the self-assembly of a chain like supramolecular arrangement. The chains are packed by van der Waals interactions between the dangling phenyl rings of the second phenylchlorovinyl substituent. In (2) a Te ... Br [3.253(1) ] secondary bond links the molecules in a chain fashion. The adjacent chains are extended into a three dimensional supramolecular array by a Br .. -C6H5 inter-chain interaction (3.680 ). Due to the secondary interactions, which includes intramolecular Te ... X secondary bonds, the polyhedron around the tellurium can be best described as a distorted pseudo-pentagonal bipyramid, with two halides in axial positions and the centriod of a phenyl ring in (1) and a bromine in (2) occupying the fifth equatorial position. Acknowledgements