Diphenyl(1-pyridyl)phosphine sulfide as a ligand in mono- and binuclear coinage metal complexes

Diphenyl(1-pyridyl)phosphine sulfide, Ph₂pyPS, 1, gives a 1:1 complex (2) with AuCl upon treatment with (C₄H₈S)AuCl. According to an X-ray diffraction analysis, this compound is isomorphous with the Ph₃PS complex. [Ph₃PAu]BF₄ and 1 give the cationic complex [Ph₃PAuSPPyPh₂]BF₄ (3). With two equivalents of the same reagent the binuclear complex 4 is generated, in which the metal atoms are S- and N-bonded. The reaction of 2 equivalents of 1 with [(tetrahydrothiophene)₂Au]ClO₄ affords the 2:1 complex 5 with the gold atom exclusively S-bonded. The analogous reaction with AgBF₄ gives the 2:1 complex 6, the structure of which has also been determined by X-ray diffraction. The silver atom is engaged in coordinative bonding with both sulfur and both nitrogen atoms in a quasi-tetrahedral environment. Addition of AgClO₄ to compound 5, and of [(MeCN)₄Cu]BF₄ to 6, gives mixed-metal complexes (7, 8) with head-to-head structures, the silver atoms being exclusively S-bonded.