Elucidating the mechanism of a two-step spin transition in a nanoporous metal−organic framework
Language
en
Article de revue
This item was published in
Journal of the American Chemical Society. 2008, vol. 130, n° 51, p. 17552-17562
American Chemical Society
English Abstract
The nanoporous metal−organic framework, Fe(bpe)<sub>2</sub>(NCS)<sub>2</sub>·3(acetone), <b>SCOF-4(Ac)</b> (where bpe is 1,2-bis(4′-pyridyl)ethane), displays a two-step spin crossover (SCO) transition (65−155 K) that is ...Read more >
The nanoporous metal−organic framework, Fe(bpe)<sub>2</sub>(NCS)<sub>2</sub>·3(acetone), <b>SCOF-4(Ac)</b> (where bpe is 1,2-bis(4′-pyridyl)ethane), displays a two-step spin crossover (SCO) transition (65−155 K) that is sensitive to the presence of acetone guest molecules. Structural analyses have revealed a structural phase transition, from tetragonal (<i>P</i>2<sub>1</sub><i>c</i>) to orthorhombic (<i>P</i>2<sub>1</sub>2<sub>1</sub>2), associated with the spin transition that defines a checkerboard-like ordering of spin sites at the high-spin:low-spin plateau. The reversible desorption of the acetone guest species is accompanied by a complex series of structural phase transitions that describe a dramatic flexing of the structure. The thermal trapping of a metastable state with 20−25% high-spin character was observed both magnetically and structurally upon rapid quenching of <b>SCOF-4(Ac)</b> to 10 and 25 K, respectively. The light-induced excited spin state trapping (LIESST) effects for <b>SCOF-4(Ac)</b> show a 55% excitation of a metastable HS state at 10 K and a characteristic <i>T</i>(LIESST) value of 52 K.Read less <
English Keywords
Spin transition
Nanoporous materials
Framework
Metal
Organic compounds
Origin
Hal imported