American Chemical Society
ic9511736_si_001.pdf (321.1 kB)

Synthesis and Spectroscopic Characterization of Halodimethyl(O-alkyl dithiocarbonato)tellurium(IV) Compounds. Crystal Structures of Me2TeCl[S2COEt] and Me2TeI[S2CO(i-Pr)]

Download (321.1 kB)
journal contribution
posted on 1996-05-08, 00:00 authored by John E. Drake, Robert J. Drake, Layla N. Khasrou, Raju Ratnani
O-Alkyl dithiocarbonate (xanthate) derivatives of halodimethyltellurium(IV), Me2TeX[S2COR], where R = Me, Et, and i-Pr and X = Cl, Br, and I, have been prepared in 75−88% yields by the reaction of the potassium salt of the appropriate dithiocarbonic acid with dimethyltellurium dihalide in equimolar ratio. The compounds were characterized by infrared, Raman, and 1H, 13C, and 125Te NMR spectroscopy. The crystal structures of Me2TeCl[S2COEt] (2) and Me2TeI[S2CO(i-Pr)] (9) were determined. Me2TeCl[S2COEt] (2), which crystallizes in the monoclinic space group P21/a (No. 14), has the cell parameters a = 9.583(2) Å, b = 10.264(3) Å, c = 22.502(2) Å, β = 97.86(1)°, V = 2192.4(8) Å3, and Z = 8, and Me2TeI[S2CO(i-Pr)] (9), which crystallizes in the triclinic space group P1̄ (No. 2), has the cell parameters a = 11.332(5) Å, b = 11.83(2) Å, c = 10.19(2) Å, α = 94.8(2)°, β = 105.53(7)°, γ = 85.10(7)°, V = 1309(3) Å3, and Z = 2. The immediate environment about tellurium in both molecules can be described as that of a sawhorse structure in which the lone pair is apparently stereochemically active and occupying an equatorial position in a distorted trigonal bipyramid. The two methyl groups occupy the other equatorial positions with a sulfur atom of the dithiocarbonate group and a halogen atom occupying the axial positions. However, intermolecular Te--I interactions between the two molecules of the asymmetric unit of 9 suggest that it is better described as dimeric, whereas the intermolecular Te--Cl associations in 2 lead to polymeric strands rather than dimers. Supramolecular associations are discussed in terms of Pauling bond orders.