Synthesis, spectroscopic and structural studies of O-methyl and O-isopropyl monothiocarbonate (monoxanthate) derivatives of dimethyl- and diphenyltellurium(IV). Crystal structures of Me(2)Te[SCO2(i-Pr)](2), Ph(2)Te[SCO2(i-Pr)](2), Me(2)TeCl[SCO(2)Me], and Me(2)TeBr[SCO2(i-Pr)]

Monothiocarbonate derivatives of diorganotellurium(IV), R(2)Te[SCO(2)R'](2), and R(2)TeX[SCO(2)R'], where R = Me, Ph; R' = Me, i-Pr; X = Cl, Br, and I, have been prepared and characterized by vibrational and H-1, C-13, and Te-125 NMR spectroscopy. Me(2)Te[SCO2(i-Pr)](2) (2): P2(1)/n (No. 14) with cell parameters a = 6.942(6) Angstrom, b = 25.599(3) Angstrom, c = 9.404(6) Angstrom, beta = 94.48(6)degrees, V = 1666(1) Angstrom(3), Z = 4, R = 0.0618, R(w) = 0.0624; Ph(2)Te[SCO2(i-Pr)](2) (4): P2(1)/n (No. 14) with a = 12360(4) Angstrom, b = 12.277(3) Angstrom, c = 15.066(3) Angstrom, beta = 102.82(2)degrees, V = 2229.1(9) Angstrom(3). Z = 4, R = 0.0368, R(w) = 0.0312; Me(2)TeCl[SCO(2)Me] (5); P2(1)/c (No. 14) with a = 5.193(2) Angstrom, b = 18.118(4) Angstrom, c = 9.613(5) Angstrom, beta = 91.31(6)degrees, V = 901.2(6) Angstrom(3), Z = 4, R = 0.0396, R(w) = 0.0361; and Me(2)TeBr[SCO2(i-Pr)] (8): P2(1)/n (No. 14) with a = 11.701(2) Angstrom, b = 6.250(2) Angstrom, c = 16.152(2) Angstrom, beta = 98.43(1)degrees, V = 1168.4(4) Angstrom(3), Z = 4, R = 0.0359, R(w) = 0.0325. In all molecules, the immediate environment about tellurium is that of the sawhorse structure in which the lone pair is assumed to be stereochemically active and occupying an equatorial position in a distorted trigonal bipyramid. In 2 and 5, the terminal oxygen atoms are oriented toward tellurium, whereas in 4, one O(i-Pr) group is oriented toward tellurium, as it is in 8. In the latter cases, the terminal oxygen atoms act as weak bridges to form a pseudo dimeric species in 4 and a pseudo polymer in 8. Supramolecular interactions in 2 and 5 lead to a sulfur-bridged dimer in the former and a chlorine-bridged polymer in the latter.