title: Anionic platinum complexes with 2-pyridylphosphines as ligands for rhodium: synthesis of zwitterionic Pt-Rh organometallic compounds.
abstract: Bimetallic zwitterionic platinum(II)-rhodium(I) complexes of the type [(C(6)F(5))(3)Pt(micro-PPy(n)Ph(3)(-)(n)Rh(CO)(2))] and [(C(6)F(5))(3)Pt(micro-PPy(n)Ph(3)(-)(n)())Rh(diene))] (n = 2, 3; Py = 2-pyridyl) have been prepared. The P end of the bridging ligands (micro-PPy(n)Ph(3)(-)(n)) is always coordinated to the Pt center, while the N-donor ends chelate the Rh atom, giving metallacycles comparable to pyrazolylborate-Rh complexes. These metallacycles can adopt two conformations, either with the Pt complex in pseudoaxial position approaching the Rh center or with the Pt complex in a remote position. The preferred conformation depends on the steric hindrance at the rhodium center. In less sterically demanding Rh-carbonyl complexes the Pt moiety gets close to the Rh moiety as this brings closer the opposite charges of the zwitterion. For diene complexes mixtures of conformers are obtained. The X-ray structures of [(C(6)F(5))(3)Pt(micro-PPhPy(2))Rh(COD)] (COD = 1,5-cyclooctadiene) and [(C(6)F(5))(3)Pt(micro-PPhPy(2))Rh(CO)(2)] are reported.
authors.affiliation: Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, E-47005 Valladolid, Spain.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Casares
authors.forename: Pablo
authors.initials: P
authors.lastname: Espinet
authors.forename: José M
authors.initials: JM
authors.lastname: Martín-Alvarez
authors.forename: Verónica
authors.initials: V
authors.lastname: Santos