Tetraorganodichalcogenoimidodiphosphinato derivatives of dimethyltellurium(IV) compounds.: Crystal structures of Me2Te[(SPPh2)2N]2, Me2TeCl[(SPPh2)2N], Me2TeI[(SPPh2)2N], and Me2TeCl[(OPPh2)(SPPh2)N]

Isolation of Me2Te[(SPPh2)(2)N](2), Me2Te[(OPPh2)(SPPh2)N](2), and the halo derivatives Me2TeX[(SPPh2)(2)N] and Me2TeX[(OPPh2)(SPPh2)N], where X = Cl, Br, I, was attempted. Four of these were characterized by single crystal X-ray diffraction, while the formation of the others was confirmed by multinuclear NMR spectroscopy. Me2Te[(SPPh2)(2)N](2), 1; P2(1)/n (No. 14) with cell parameters a = 14.908(3) Angstrom, b = 11.122(5) Angstrom, c = 30.384(6) Angstrom, beta = 92.67(2)degrees, V = 5032(2) Angstrom(3), Z = 4, R = 0.0661, R-w = 0.0696. Me2TeCl[(SPPh2)(2)N], 2; P (1) over bar (No. 2) with cell parameters a = 10.553(2) Angstrom, b = 15.512(2) Angstrom, c = 8.769(3) Angstrom, alpha = 103.19(2)degrees, beta = 94.27(2)degrees, gamma = 85.76(2)degrees, V = 1391.3(7) Angstrom(3), Z = 2, R = 0.0377, R-w = 0.0328. Me2TeI[(SPPh2)(2)N], 4; P (1) over bar (No. 2) with cell parameters a = 10.954(3) Angstrom, b = 15.580(3) Angstrom, c = 8.751(3) Angstrom, alpha = 103.49(2)degrees, beta = 93.11(3) Angstrom, gamma = 87.33(2)degrees, V = 1449.3(7) Angstrom(3), Z = 2, R = 0.0586, R-w = 0.0613. Me2TeCl[(OPPh2)(SPPh2)N], 6; P2(1)/c (No. 14) with cell parameters a = 10.441(9) Angstrom, b = 13.672(10) Angstrom, c = 19.521(9) Angstrom, beta = 97.16(6)degrees, V = 2764(3) Angstrom(3), Z = 4, R = 0.0546, R-w = 0.0572. The immediate environment about Te is that of a sawhorse structure in which the lone pair is apparently stereochemically active and occupying an equatorial position in a distorted trigonal bipyramid. In 1, 2, and 4, one sulfur atom of (SPPh2)(2)N occupies an axial position. If the second sulfur atom is included in the coordination sphere, then the environment about Te becomes distorted octahedral, for 1, and square pyramidal, for 2 and 4. By contrast, in Me2TeCl[(OPPh2)(SPPh2)N], 6, the oxygen atom, rather than sulfur, is bound to tellurium in the axial position, with the S atom, at best, having a very weak interaction with Te.