Adducts of tellurium tetrachloride with allyl alcohol and allyl acetate: 1,2-vs 1,3-addition and structure and dynamics of Te center dot center dot center dot O interactions in different phases

摘要

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, H-1-H-1-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)-sigma*(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 H-1-H-1-NOESY experiments show the cyclic structures to exist in solution as well, with little changes in their geometry compared to the solid state. [References: 38]