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Magnetic bistability in a cobalt bis(dioxolene) complex: long-lived photoinduced valence tautomerism
Robert D Schmidt1, David A Shultz, James D Martin
1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
Abstract:
The thermal- and photoinduced valence tautomerism of a cobalt bis(dioxolene) complex is described. The thermal conversion is precipitous, complete within 10 K, and is accompanied by a 5 K hysteresis loop (107 K < T(1/2) < 112 K). Rapid thermal quenching (300 K --> 10 K in ca. 5 s) and photoinduced valence tautomerism result in trapping of the metastable Co(II)-state at low temperatures through intermolecular hydrogen bonding. This lattice stabilization results in unmatched kinetic and thermal stability for a valence tautomer from 10-50 K, with residual hs-Co(II) persisting until about 90 K.
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