title: Synthesis and dynamic behaviour of zwitterionic [M(η(6)-C6H5-BPh3)(coe)2] (M = Rh, Ir) cyclooctene complexes.
abstract: The synthesis and structural characterization of zwitterionic [(η(6)-C6H5-BPh3)M(coe)2] (M = Rh, Ir) cyclooctene complexes is described. Both complexes exhibit an unusual exo-endo conformation of both cyclooctene ligands in the solid state. However, an equilibrium between the endo-endo and exo-endo rotational isomers arising from the hindered rotation about the metal-cyclooctene bond is observed in solution. Rotational barriers of around 65 kJ mol(-1) (Rh) and 84 kJ mol(-1) (Ir) have been determined by 2D EXSY NMR spectroscopy. The rotation process has also been studied by DFT calculations that showed that the dynamic behaviour is a consequence of the oscillation of the cyclooctene ligands about the metal-olefin bond instead of completing a full rotation.
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea-ISQCH, Universidad de Zaragoza-CSIC, Facultad de Ciencias, C/Pedro Cerbuna, 12, 50009 Zaragoza, Spain. perez@unizar.es.
authors.forename: Jesús J
authors.initials: JJ
authors.lastname: Pérez-Torrente
authors.forename: Marta
authors.initials: M
authors.lastname: Angoy
authors.forename: Daniel
authors.initials: D
authors.lastname: Gómez-Bautista
authors.forename: Adrián
authors.initials: A
authors.lastname: Palacios
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Jiménez
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Modrego
authors.forename: Ricardo
authors.initials: R
authors.lastname: Castarlenas
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Lahoz
authors.forename: Luis A
authors.initials: LA
authors.lastname: Oro