title: Step-by-step uncoordination of the pyrazolyl rings of hydrotris(pyrazolyl)borate ligands in comlexes of Rh and RhIII.
abstract: Compounds of rhodium(I) and rhodium(III) that contain ancillary hydrotris(pyrazolyl)borate ligands (Tp') react with monodentate and bidentate tertiary phosphanes in a step-wise manner, with incorporation of P-donor atoms and concomitant replacement of the Tp' pyrazolyl rings. Accordingly, [Rh(kappa3-TpMe2)(C2H4)(PMe3)] (1b), converts initially into [Rh(kappa2-TpMe2)-(PMe3)2] (3), and then into [Rh(kappa1-TpMe2)-(PMe3)3] (2) upon interaction with PMe3 at room temperature, in a process which can be readily reversed under appropriate experimental conditions. Full disengagement of the Tp' ligand is feasible to give Tp' salts of rhodium(I) complex cations, for example, [Rh(CO)(dppp)2]-[TpMe2,4-Cl] (5; dppp = Ph2P(CH2)3PPh2), or [Rh(dppp)2][TpMe2,4-Cl] (6). Bis(hydride) derivatives of rhodium(III) exhibit similar substitution chemistry, for instance, the neutral complex [Rh(Tp)-(H)2(PMe3)] reacts at 20 degrees C with an excess of PMe3 to give [Rh(H)2-(PMe3)4][Tp] (9b). Single-crystal X-ray studies of 9b, conducted at 143 K, demonstrate the absence of bonding interactions between the [Rh(H)2(PMe3)4]+ and Tp ions, the closest Rh...N contact being at 4.627 A.
authors.affiliation: Instituto de Investigaciones Químicas, Departamento de Química Inorgánica, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Spain. paneque@cica.es/guzman@cica.es
authors.forename: M
authors.initials: M
authors.lastname: Paneque
authors.forename: S
authors.initials: S
authors.lastname: Sirol
authors.forename: M
authors.initials: M
authors.lastname: Trujillo
authors.forename: E
authors.initials: E
authors.lastname: Carmona
authors.forename: E
authors.initials: E
authors.lastname: Gutiérrez-Puebla
authors.forename: M A
authors.initials: MA
authors.lastname: Mongue
authors.forename: C
authors.initials: C
authors.lastname: Ruiz
authors.forename: F
authors.initials: F
authors.lastname: Malbosc
authors.forename: C
authors.initials: C
authors.lastname: Serra-Le Berre
authors.forename: P
authors.initials: P
authors.lastname: Kalck
authors.forename: M
authors.initials: M
authors.lastname: Etienne
authors.forename: J C
authors.initials: JC
authors.lastname: Daran