title: Transition metal complexes of the chelating phosphine borane ligand Ph2PCH2Ph2P.BH3.
abstract: Chromium and ruthenium complexes of the chelating phosphine borane H(3)B.dppm are reported. Addition of H(3)B.dppm to [Cr(CO)(4)(nbd)](nbd = norbornadiene) affords [Cr(CO)(4)(eta1-H(3)B.dppm)] in which the borane is linked to the metal through a single B-H-Cr interaction. Addition of H(3)B.dppm to [CpRu(PR(3))(NCMe)(2)](+)(Cp =eta5)-C(5)H(5)) results in [CpRu(PR(3))(eta1-H(3)B.dppm)][PF(6)](R = Me, OMe) which also show a single B-H-Ru interaction. Reaction with [CpRu(NCMe)(3)](+) only resulted in a mixture of products. In contrast, with [Cp*Ru(NCMe)(3)](+)(Cp*=eta5)-C(5)Me(5)) a single product is isolated in high yield: [Cp*Ru(eta2-H(3)B.dppm)][PF(6)]. This complex shows two B-H-Ru interactions. Reaction with L = PMe(3) or CO breaks one of these and the complexes [Cp*Ru(L)(eta1-H(3)B.dppm)][PF(6)] are formed in good yield. With L = MeCN an equilibrium is established between [Cp*Ru(eta2-H(3)B.dppm)][PF(6)] and the acetonitrile adduct. [Cp*Ru (eta2-H(3)B.dppm)][PF(6)] can be considered as being "operationally unsaturated", effectively acting as a source of 16-electron [Cp*Ru (eta1-H(3)B.dppm)][PF(6)]. All the new compounds (apart from the CO and MeCN adducts) have been characterised by X-ray crystallography. The solid-state structure of H(3)B.dppm is also reported.
authors.affiliation: Department of Chemnistry, University of Bath, Bath BA2 7AY, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Merle
authors.forename: Gabriele
authors.initials: G
authors.lastname: Koicok-Köhn
authors.forename: Mary F
authors.initials: MF
authors.lastname: Mahon
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Frost
authors.forename: Giuseppe D
authors.initials: GD
authors.lastname: Ruggerio
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Weller
authors.forename: Michael C
authors.initials: MC
authors.lastname: Willis