title: Synthesis and characterization of neutral and anionic carbonyl derivatives of palladium(II).
abstract: The action of CO on the solvento-complexes cis-[PdR2(thf)2] [R = C6F5 (1), C6Cl5 (2)] at low temperature gives cis-[PdR2(CO)2] [R = C6F5 (3), C6Cl5 (4)] in good yield by simple replacement of the highly labile thf molecules. These are rare cases of Pd(II) dicarbonyl compounds, whose characterization relies on spectroscopic and analytic data. The crystal structure of the square-planar platinum homologue cis-[Pt(C6Cl5)2(CO)2] is also presented. CO can split the double bridging-system in the dinuclear species [{PdR2}2(mu-X)2]2- giving the homologous series of anionic monocarbonyl Pd(II) derivatives with formula [cis-PdR2X(CO)]- (5-10: R = C6F5, C6Cl5; X = Cl, Br, I), which were isolated (except for the R = C6F5 and X = I) and suitably characterized. Characterization includes the crystal and molecular structure of [PPh3Me][cis-Pd(C6F5)2Br(CO)] (6'). The anionic species [NBu4][cis-Pd(C6F5)2Cl(CO)] (5) reacts with neutral cis-[Pd(C6F5)2(CO)2] (3) under CO extrusion, affording the dinuclear derivative [NBu4][{Pd(C6F5)2(CO)}2(mu-Cl)] (11), which contains a single unsupported halide bridge (X-ray diffraction). Complex 11 can be considered as modelling a possible intermediate step in intermolecular CO substitution reactions that are easily undergone by Pd(II) halo carbonyl species.
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, Facultad de Ciencias, Universidad de Zaragoza-C.S.I.C, C/Pedro Cerbuna 12, E-50009, Zaragoza, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Ara
authors.forename: Juan
authors.initials: J
authors.lastname: Forniés
authors.forename: Antonio
authors.initials: A
authors.lastname: Martín
authors.forename: L Francisco
authors.initials: LF
authors.lastname: Martín
authors.forename: Babil
authors.initials: B
authors.lastname: Menjón
authors.forename: Helvia
authors.initials: H
authors.lastname: Miedes