TRIS(PHENYLTHIOMETHYL)PHOSPHANE SULFIDE AND SELENIDE, (PHSCH(2))(3)PX(X=S, SE), AS AMBIDENTATE LIGAND SYSTEMS IN COPPER(I) COMPLEXES

Triphenylphosphite has been converted into tris(phenylthiomethyl)phosp hane (1) by reaction with LiCH(2)SPh/DABCO, and subsequently into the corresponding sulfide (2) and selenide (3) by treatment with elemental sulfur or selenium, respectively. Ligands 2 and 3 react with copper(I ) halides CuX (X = Cl, Br, I) in polar organic solvents to give either 1:1 (X = Cl: 4, 7, X = Br: 5, 8) or 1:2 complexes (X = Br: 9, X = I: 6, 10). The crystal structures of five of these complexes have been de termined by single crystal X-ray diffraction studies. All compounds of the type [(PhSCH(2))(3)P = S/Se]CuX (X = Cl, Br) form centrosymmetric al dinuclear complexes featuring a four-membered ring core Cu-2[S/Se]( 2) fused to two five-membered rings Cu[S/Se]PCS through common trans e dges. Only one of the three phenyl-thiomethyl functions is involved in coordination to a metal center. The compound [(PhSCH(2))(3)P=S](CuI)( 2) (6) is associated into a centrosymmetrical tetranuclear complex con taining two four-membered rings (ICu2S) bridged via iodine atoms in 1, 3-cis positions. The ligand is found to employ two of its PhSCH(2) fun ctions for metal coordination, giving rise to two five-membered rings fused to the four-membered rings via neighbouring edges. In all cases, therefore, the P=S/Se functions of the ligands are the preferred dono r sites, which are used for the building of bridgehead structural unit s of polynuclear complexes.