Silver(I) bromide complexes of the rigid diphosphanes 1,2-bis(diphenylphosphano)benzene (dppbz) and 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene (xantphos): Crystal structures of [Ag(μ 2-Br)(dppbz)] 2, [AgBr(xantphos)] and [AgBr(xantphos)(py2SH)]

• Published in: Polyhedron 2007-05, Vol.26 (8), p.1634-1642
• Main Authors: Kaltzoglou, A., Cox, P.J., Aslanidis, P.
• Format: Article
• Language: English
• Subjects: Crystal structures; Pyridine-2-thione; Rigid diphosphanes; Silver(I) complexes
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2006.12.006

The behaviour of the diphos ligands 1,2-bis (diphenylphosphano)benzene (dppbz) and 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene (xantphos) towards coordination of Ag(I) bromide in the presence of pyridine-2-thione has been investigated. Both diphosphanes adopt the chelating coordination mode, however two types of products have been obtained, namely a halide bridged dimer with tetrahedrally coordinated Ag I centers for dppbz and monomeric trigonal complexes in the case of xantphos. Reaction of silver(I) bromide with equimolar amounts of the rigid diphos ligands 1,2-bis(diphenylphosphano)benzene (dppbz) and 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene (xantphos) in acetone and acetonitrile led to the corresponding chelates [Ag(μ 2-Br)(dppbz)] 2 ( 1) and [AgBr(xantphos)] ( 2). Treatment of 1 and 2 with pyridine-2-thione (py2SH) in ethanol gave the mixed-ligand complexes [AgBr(dppbz)(py2SH)] ( 3) and [AgBr(xantphos)(py2SH)] ( 4), respectively. Compounds 1, 2 and 4 have been characterized by X-ray diffraction, establishing distorted tetrahedral or trigonal planar coordination geometries of the silver atoms.