Stereoselective synthesis, molecular structure and NBO analyses of cis-3,5-di(chloromethyl)-1,4-oxatellurane(IV) 4,4-dichloride

Tellurium tetrachloride and diallyl ether give stereoselectively cis-3,5-di(chloromethyl)-1,4-oxa-tellurane(IV) 4,4-dichloride. The structure was determined by single crystal X-ray diffraction. The coordination around the Te-IV ion is a distorted psi trigonal bipyramid with two chlorine atoms in the axial positions. Two of the equatorial sites are occupied by carbon atoms, with the lone electron pair located at the third position. The six-membered heterocycle displays a chair conformation. The crystal structure consists of ribbons with Te ... Cl contacts. The NBO (Natural Bond Order) analyses carried out by both HF/STO-3G* and HF/LANL1DZ level of theory gave different results. No intermolecular interaction (> 1 kcal mol(-1)) was found by HF/STO-3G*, whereas the main interaction can be seen between a lone pair of Cl(2) and the antibonding orbital between Tell) and C(1) by RHF/LANL1DZ (1.1 kcal mol(-1)). (C) 1997 Elsevier Science Ltd.