Adducts of Tellurium Tetrachloride with Allyl Alcohol and Allyl Acetate: 1,2- vs 1,3-Addition and Structure and Dynamics of Te···O Interactions in Different Phases

Abstract

The compounds Cl3Te[CH2CH(Cl)CH2O(H)···]·Cl2Te[−CH2CH(Cl)CH2O−] (1) and Cl3Te[CH2CH(CH2Cl)OC(CH3)O···] (2) were prepared by the reaction of TeCl4 with allyl alcohol and allyl acetate, respectively. Their molecular and crystal structures were investigated by single-crystal X-ray analysis, 1H−1H-NOESY experiments, IR spectroscopy, and ab initio geometry optimization. 1 is a composite compound, whose subunits Cl2Te[−CH2CH(Cl)CH2O−] (1A) and Cl3Te[CH2CH(Cl)CH2O(H)···] (1B) are linked in the solid state via Te···Cl−Te and O···H−O bridges. Both Te atoms are involved in similar five-membered rings, having a covalent Te−O bond in one case (1A) and a dative Te···O bond in the other (1B). In the solid state, both Te atoms are pentacoordinate with pseudo-octahedral configurations. Formation of 2 is accompanied by a 3,2-migration of the acetate group, leading to a 1,3-addition of TeCl4 to allyl acetate and a six-membered ring via an intramolecular dative Te···O interaction. In the solid state, single molecules of 2 are linked by weak CH2Cl···Te contacts, the Te atom being hexacoordinate with a distorted-octahedral configuration. Since reaction of 1 with acetyl chloride also gives 2, the 1,3-addition product of TeCl4 with allyl acetate must be thermodynamically more stable than the corresponding 1,2-addition product, a conclusion that is supported by ab initio calculations. Ab initio calculations (MP2/LANL2DZP) for Cl3Te[CH2CH(Cl)CH2O(H)···] (1B) and 2 revealed strong n(O)−σ*(Te−Cl) and Coulombic interactions for the Te···O bonds, which are significantly longer in the isolated molecules than in the solid state. Multinuclear NMR spectroscopy and 1H−1H-NOESY experiments show the cyclic structures to exist in solution as well, with little changes in their geometry compared to the solid state.