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RESEARCH PRODUCT

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

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The compounds Cl 3 Te[CH 2 CH(Cl)CH 2 O(H)...].Cl 2 Te[-CH 2 CH(Cl)CH 2 O-] (1) and Cl 3 Te-[CH 2 CH(CH 2 Cl)OC(CH 3 )=O...] (2) were prepared by the reaction of TeCl 4 with allyl alcohol and allyl acetate, respectively. Their molecular and crystal structures were investigated by single-crystal X-ray analysis, 1 H- 1 H-NOESY experiments, IR spectroscopy, and ab initio geometry optimization. 1 is a composite compound, whose subunits Cl 2 Te[-CH 2 CH(Cl)-CH 2 O-] (1A) and Cl 3 Te[CH 2 CH(Cl)CH 2 O(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 TeCl 4 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 CH 2 Cl...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 TeCl 4 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 Cl 3 Te[CH 2 CH(Cl)CH 2 O(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 1 H- 1 H-NOESY experiments show the cyclic structures to exist in solution as well, with little changes in their geometry compared to the solid state.