A thallium(I) tetranuclear cubic cage unit in an interpenetrated supramolecular polymer: A new precursor for the preparation of Tl2O3 nanostructures

A new thallium(I) supramolecular polymer, [Tl-4(mu(3)-4-BN)(4)](n) (1) [9-HBN = 4-hydroxy benzonitrile], with a disordered cubic cage structural unit has been synthesized and characterized. The single-crystal X-ray data of compound 1 shows one type of Tl-I ion in the tetranuclear cubic cage structure with a coordination number of three. In addition to two intra cage thallophilic interactions in 1, each thallium(I) atom has a weak Tl center dot center dot center dot N secondary interaction with the nitrile group of the 4-BN- ligand. Finally the Tl-ions attain the O3Tl center dot center dot center dot NTl2 coordination sphere with a stereo-chemically 'active' electron lone pair on the metal. The self assembly between the benzonitrile groups of one cubic cage structure with an adjacent one with a Tl center dot center dot center dot N short contact, by pi-pi stacking and weak hydrogen bonding interactions, results in the formation of a new interpenetrating thallium(I) supramolecular polymer. The thermal stability of 1 was studied by thermo gravimetric (TG) and differential thermal analyses (DTA). Nanostructures of thallium(III) oxide were prepared from a calcination process of compound 1 fine powder at 743 K. These nanostructures were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). (C) 2011 Elsevier Ltd. All rights reserved.