title: Reversible breaking and forming of metal-ligand coordination bonds: temperature-triggered single-crystal to single-crystal transformation in a metal-organic framework.
abstract: Yb(C(4)H(4)O(4))(1.5)] undergoes a temperature-triggered single-crystal to single-crystal transformation. Thermal X-ray single-crystal studies showed a reversibly orchestrated rearrangement of the atoms generated by the breaking/formation of coordination bonds, in which the stoichiometry of the compound remains unchanged. The transformation occurs on heating the crystal at approximately 130 degrees C. This uncommon behavior was also studied by thermal methods, FTIR spectroscopy, and thermodiffractometry. Both polymorphs, alpha (room-temperature form) and beta (high-temperature form), are proven to be active heterogeneous catalysts; the higher catalytic activity of beta is owed to a decrease in the Yb coordination number. A mechanism based on spectroscopic evidence and involving formation of the active species Yb-O-OH is proposed for the sulfide oxidation.
authors.affiliation: Area de Química General e Inorgánica Dr. G. F. Puelles, Facultad de Química, Bioquímica y Farmacia, Chacabuco y Pedernera, Universidad Nacional de San Luis, 5700 San Luis, Argentina.
authors.forename: María C
authors.initials: MC
authors.lastname: Bernini
authors.forename: Felipe
authors.initials: F
authors.lastname: Gándara
authors.forename: Marta
authors.initials: M
authors.lastname: Iglesias
authors.forename: Natalia
authors.initials: N
authors.lastname: Snejko
authors.forename: Enrique
authors.initials: E
authors.lastname: Gutiérrez-Puebla
authors.forename: Elena V
authors.initials: EV
authors.lastname: Brusau
authors.forename: Griselda E
authors.initials: GE
authors.lastname: Narda
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Monge