title: Monodentate phosphine substitution in [Pd(κ3-dppf)(PR3)][BF4]2(dppf = 1,1'-bis(diphenylphosphino)ferrocene) compounds.
abstract: The ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf) is commonly employed in a variety of catalytic systems. There are a variety of coordination modes known for dppf, the least studied being the κ3coordination mode, in which both phosphorus atoms and the iron atom of dppf interact with another metal center. One such compound is the previously reported [Pd(κ3-dppf)(PPh3)]2+. A series of related compounds, [Pd(κ3-dppf)(P(p-C6H4R)3)]2+(R = OCH3, CH3, F and CF3), has been synthesized and characterized. The X-ray crystal structure of [Pd(dppf)(P(p-C6H4F)3)][BF4]2was determined. Electrochemical and computational studies indicate that the electron donor ability of the P(p-C6H4R)3ligands influences the properties of these compounds. Substitution reactions of the P(p-C6H4R)3ligands have been examined, and, in general, the more electron donating P(p-C6H4R)3ligands completely replace the less electron donating ones. The kinetics of the reaction of [Pd(κ3-dppf)(P(p-C6H4F)3)]2+with P(p-C6H4OCH3)3indicate that the reaction proceeds through a dissociative mechanism, contrary to the associative substitutions prevalent in square planar palladium(ii) chemistry.
authors.affiliation: Department of Chemistry, Lafayette College, Easton, PA 18042, USA. nataroc@lafayette.edu.
authors.forename: K D
authors.initials: KD
authors.lastname: Cabrera
authors.forename: A T
authors.initials: AT
authors.lastname: Rowland
authors.forename: J M
authors.initials: JM
authors.lastname: Szarko
authors.forename: P L
authors.initials: PL
authors.lastname: Diaconescu
authors.forename: M W
authors.initials: MW
authors.lastname: Bezpalko
authors.forename: W S
authors.initials: WS
authors.lastname: Kassel
authors.forename: C
authors.initials: C
authors.lastname: Nataro