Reaction of large-bite ligands with various tellurium compounds: Synthesis and structural characterization of [Te 2(μ-Cl) 2{(SPPh 2) 2N} 2], [(4-MeOC 6H 4TeCl 3) 2{μ-Ph 2P(S)CH 2CH 2P(S)Ph 2}] and [Te 2(μ-Ph 2PS 2) 2] representing novel types of tellurium complexes

Abstract

The three title compounds have been synthesized and their structures determined by X-ray crystallography. [Te 2(μ-Cl) 2{(SPPh 2) 2N} 2], 1, is a dinuclear square planar Te(II) complex where each Te atom is coordinated to the two sulfur atoms of the bidentate dithiolate ligand and to the two bridging chloride ligands. The Te–S bond lengths are 2.4980(8) and 2.5054(8) Å, while the Te–Cl bond lengths are 2.9065(9) and 2.9230(9) Å. In [(4-MeOC 6H 4TeCl 3) 2{μ-Ph 2P(S)CH 2CH 2P(S)Ph 2}], 2, the dithio ligand is neutral and adds a molecule of [4-MeOC 6H 4TeCl 3] at each sulfur atom, thus bridging the two Te(IV) atoms. The coordination of both tellurium atoms is ψ-octahedral with the anisyl group and a lone pair of electrons in axial positions. The Te–S bonds, 2.7747(6) and 2.8198(5) Å, are surprisingly weak while the Te–Cl bonds lie in the range 2.4247(5) to 2.5343(6) Å, those trans to Te–S being shortest. [Te 2(μ-Ph 2PS 2) 2], 3, is a binuclear Te(I) complex, mainly held together by a Te–Te bond of 2.7298(5) Å. Both anisobidentate diphenyldithiophosphinate ligands bridge the two tellurium atoms. The resulting coordination around each tellurium is best described as T-shaped with the Te–Te bond along the stem. In the asymmetric near linear S–Te–S system, the short Te–S bonds are 2.487(2) and 2.495(2) Å while the long bonds are 2.947(2) and 3.033(2) Å, respectively. The strongly different trans influences of the dithio ligands of 1 and 2 are discussed and it is suggested that they are dependent upon the basicity of the sulfur atoms.