title: A Recoverable Ruthenium Aqua Complex Supported on Silica Particles: An Efficient Epoxidation Catalyst.
abstract: The preparation and characterization of complexes with a phosphonated terpyridine (trpy) ligand (trpy-P-Et) and a bidentate pyridylpyrazole (pypz-Me) ligand, with formula [RuII(trpy-P-Et)(pypz-Me)X]n+(2: X=Cl, n=1; 3: X=H2O, n=2), is described, together with the anchoring of 3 on two types of supports: mesoporous silica particles (SP) and silica-coated magnetic particles (MSP). Aqua complex 3 is easily obtained by heating 2 in refluxing water and exhibits a two-electron RuIV/IIredox process. It was anchored on SP and MSP supports by two different synthetic strategies, yielding the heterogeneous systems SP@3 and MSP@3, which were fully characterized by IR and UV/Vis spectroscopy, SEM, cyclic voltammetry, and differential pulse voltammetry. Catalytic olefin epoxidation was tested with molecular complex 3 and its SP@3 and MSP@3 heterogeneous counterparts, including reuse of the heterogeneous systems. The MSP@3 material can be easily recovered by a magnet, which facilitates its reusability.
authors.affiliation: Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, Campus de Montilivi, 17003, Girona, Spain.
authors.forename: Íngrid
authors.initials: Í
authors.lastname: Ferrer
authors.affiliation: Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, Campus de Montilivi, 17003, Girona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Fontrodona
authors.affiliation: Institut de Ciència de Materials de Barcelona, ICMAB (CSIC), Campus UAB, 08193, Bellaterra, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Roig
authors.affiliation: Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, Campus de Montilivi, 17003, Girona, Spain.
authors.forename: Montserrat
authors.identifier: http://orcid.org/0000-0002-2949-8178
authors.initials: M
authors.lastname: Rodríguez
authors.affiliation: Departament de Química and Serveis Tècnics de Recerca, Universitat de Girona, Campus de Montilivi, 17003, Girona, Spain.
authors.forename: Isabel
authors.identifier: http://orcid.org/0000-0003-4805-8394
authors.initials: I
authors.lastname: Romero
keywords: N ligands; epoxidation; heterogeneous catalysis; ruthenium; supported catalysts