REVERSIBLE BREAKING AND FORMING OF METAL-LIGAND COORDINATION BONDS: TEMPERATURE TRIGGERED SINGLE-CRYSTAL-TO-SINGLE-CRYSTAL TRANSFORMATION IN A METAL–ORGANIC FRAMEWORK

M. C. BERNINI; F. GÁNDARA; M. IGLESIAS; N. SNEJKO; E. GUTIERREZ PUEBLA; E.V.BRUSAU; G.E.NARDA; M.A.MONGE

Chemistry. An european journal

Wiley- VCH

Lugar: Weinheim; Año: 2009 vol. 15 p. 4896 - 4905

1521-3765

Abstract: [Yb(C4H4O4)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, inwhich the stoichiometry of the compound remains unchanged. The transformation occurs on heating the crystal at 130 8C. This uncommon behavior was also studied by thermal methods, FTIR spectroscopy, and thermodiffractometry. Both polymorphs, a (roomtemperature form) and b (high-temperature form), are proven to be active heterogeneous catalysts; the higher catalytic activity of b is owed to a decrease in the Yb coordination number. A mechanism based on spectroscopic evidence and involving formation of the active species YbOOH is proposed for the sulfide oxidation.