NEW CYCLIC TELLURIDES - SYNTHESIS, REACTION AND LIGAND PROPERTIES OF 2,2,6,6-TETRAMETHYL-1-OXA-4-TELLURA-2,6-DISILACYCLOHEXANE (C6H16OSI2TE) - X-RAY STRUCTURE DETERMINATION OF C6H16OSI2TEI2

A new tellurium-containing heterocyclic compound, 2,2,6,6-tetramethyl-1-oxa-4-tellura-2,6-disilacyclohexane (C6H16OSi2Te) (1), has been prepared by treatment of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane with sodium telluride. Mononuclear and dinuclear palladium complexes of this telluride have been prepared by the reaction of 1 with PdCl2(PhCN)2 and Na2PdCl4, respectively. The following new derivatives of 1 have also been produced: C6H16OSi2TeI2 (2), C6H16OSi2TeBr2, C6H16OSi2TeCl2, C6H16OSi2Te(CH3)I, and C6H16OSi2Te(CH2Ph)Br. IR, H-1 and C-13 NMR and mass spectral data of these new compounds are reported and discussed. H-1 NMR studies revealed that in CDCl3 solution both telluronium salts reductively eliminate alkyl halide. The crystal structure of compound 2 has been determined by X-ray diffraction. The compound crystallizes in the monoclinic space group, P2(1)/c, with four molecules in a unit cell of dimensions a 12.960(3), b 8.846(2), c 13.754(4) angstrom, beta 92.44(2)-degrees, R = 0.049, and R(w) = 0.067 for 3599 unique reflections with \F0\ > 3-sigma-(F0). The compound forms a six-membered ring of a slightly displaced boat type. The geometry about the Te atom is pseudo-octahedral, with two carbon atoms (Te-C = 2.156(7) and 2.137(6) angstrom) and two iodine atoms of the neighbouring molecules (weak intermolecular bonds, Te...I = 3.769 and 3.806 angstrom) in the equatorial positions and two iodine atoms (Te-I = 2.909(1) and 2.913(1) angstrom) in the axial positions.