title: Synthesis and structural characterization of novel Re(i) tricarbonyl complexes anchored on a phosphinoarylbenzylamine and a phosphinoaryloxazoline generated in situ.
abstract: Reduction of the amide or replacement of the hydroxyl by a bromide in 2-(diphenylphosphanyl)-N-(2-hydroxyethyl)benzamide (H2PNO) yielded the compounds 2-(diphenylphosphanyl)-N-(2-hydroxyethyl)benzylamine (H2CH2PNO, 1) and N-(2-bromoethyl)-2-(diphenylphosphanyl)benzamide (HPNBr, 2), respectively. Compound 2 is obtained in low yield and, depending on the reaction conditions, is mixed with starting material or with a product which has been identified as 2-(2-diphenylphosphinophenyl)oxazoline (PPh3oxaz, 3). Compounds 1 and 2 react with (NEt(4))(2)[ReBr(3)(CO)(3)], leading to the complexes [Re(CO)(3)(kappa(2)-H(2)CH(2)PNO)Br] (4) and [Re(CO)(3)(kappa(2)-PPh(3)oxazBr)] (5), fully characterized by (1)H and (31)P NMR spectroscopy and X-ray crystallographic analysis. Complex 5 is the first example of a Re(I) tricarbonyl anchored on a phosphorus-oxazoline ligand, which has been generated during the course of complex formation. In the unexpected and unusual complex 5, the Re atom is stabilized by a bidentate 2-(2-diphenylphosphinophenyl)oxazoline, by a bromide, and by three facially arranged carbonyl groups. In complex 4, the carbonyl groups are also facially coordinated to the metal center and the other three remaining coordination positions are occupied by a bromide and by the bidentate (P, N) ligand 2-(diphenylphosphanyl)-N-(2-hydroxyethyl)benzylamine.
authors.affiliation: Departamento de Química, ITN, Estrada Nacional 10, 2686-953 Sacavém Codex, Portugal.
authors.forename: Torsten
authors.initials: T
authors.lastname: Kniess
authors.forename: João D G
authors.initials: JD
authors.lastname: Correia
authors.forename: Angela
authors.initials: A
authors.lastname: Domingos
authors.forename: Elisa
authors.initials: E
authors.lastname: Palma
authors.forename: Isabel
authors.initials: I
authors.lastname: Santos