Binuclear copper(I) complexes containing bis(diphenylphosphino)ethane bridges: the crystal structure of bis[{mu-bis(diphenylphosphino)ethane} (pyridine-2-thione)copper(I) bromide]

Treatment of copper(I) bromide with one equivalent of 1.2-bis(diphenylphosp hino)ethane (dppe), followed by the addition of one equivalent of heterocyc lic thione L {L = pyridine-2-thione (py2SH), pyrimidine-2-thione (pymtH), i midazole-2-thione (imtH), benz-1,3-imidazoline-2-thione (bzimtH(2)), benz-1 ,3-thiazoline-2-thione (bztztH), 2-mercapto-1-methylimidazole (meimtH), 4,6 -dimethylpyrimidine-2-thione (dmpymtH), and 6-ethoxybenz-1,3-thiazoline-2-t hione (etObztztH) in dry acetone affords the dinuclear complexes [CuBr(dppe )(L)](2) in ca. 60-80% yield. These compounds have been characterized by th eir IR, far-IR, UV-Vis and H-1 NMR spectroscopic data. The crystal structur e of [CuBr(dppe)(py2SH)](2) has been determined by single-crystal X-ray dif fraction methods. In the dinuclear complex in which the two monomers are re lated by inversion, each Cu(I) centre exhibits a tetrahedral coordination s phere involving, besides the bromine, the exocyclic sulfur of one thione mo lecule and two phosphor atoms from two different diphosphine units. Vibrati onal, electronic and H-1 NMR spectral data of the complexes are discussed i n relation to the structure. (C) 2000 Elsevier Science Ltd. All rights rese rved.