NEW ARYLTELLURIUM(II) DIORGANOPHOSPHINODITHIOATES - CRYSTAL-STRUCTUREOF RED (294-K) AND YELLOW (173-K) (1)(INFINITY)[PHTES(S)PPH(2)], A SUPRAMOLECULAR POLYMER DISPLAYING AN UNUSUAL COORDINATION PATTERN OF THEPHOSPHINODITHIOATO LIGAND

Aryltellurium(II) diorganophosphinodithioates, ArTeS(2)PR(2), were pre pared by treating Ar2Te2 with R(2)P(S)-S-S-P(S)R(2) (Ar = Ph, p-tolyl; R = Me, Et, Ph) (method (a)) or PhTeCl(3) with NaS(2)PR(2).2H(2)O (R = Me, Et) (method (b)). The compounds were characterized by IR, H-1 an d P-31 NMR, and mass spectroscopy. The compound PhTeS(S)PPh(2) display s thermochromism; a yellow form is observed below -60 degrees C and a red form at room temperature. The crystal structure of PhTeS(S)PPh, wa s investigated using X-ray diffraction, at both low and room temperatu re. In both cases the molecules are associated in polymeric chains thr ough unusual monodentate biconnective phosphinodithioato bridges, in w hich the sulfur atom single bonded to phosphorus of the molecule units is involved in secondary bonding to the tellurium atoms of a symmetry related molecule (Te-S(-P) 2.406 Angstrom, Te...S(-P) 3.383 Angstrom at 173 K and, respectively, Te-S(-P) 2.401 Angstrom, Te...S(-P) 3.422 Angstrom at 294 K). The sulfur atoms doubly bonded to phosphorus are n ot involved in coordination to tellurium (non-bonding Te...S(=P) 3.989 Angstrom at 173 K, and 3.964 Angstrom at 294 K, respectively).