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X‐ray study of the light‐induced metastable state of a spin‐crossover compound
Author(s) -
Kusz Joachim,
Spiering Hartmut,
Gütlich Philipp
Publication year - 2000
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889899014739
Subject(s) - spin crossover , metastability , chemistry , spin states , excited state , crystallography , isostructural , spin transition , atomic physics , crystal structure , materials science , physics , inorganic chemistry , organic chemistry
Iron(II) complexes exhibiting thermal spin crossover may be converted from the 1 A 1 low‐spin (LS) state to the 5 T 2 high‐spin (HS) state by irradiation with green light (light‐induced excited spin‐state trapping, LIESST). The lifetime of the metastable LIESST state may be sufficiently long for X‐ray diffraction study. The lattice parameters of a single crystal of [Fe(ptz) 6 ](BF 4 ) 2 (ptz = propyltetrazole) were measured between 300 and 10 K, while the crystal changed from the HS to the LS state near 135 K. Using the green light (514 nm) of an argon‐ion laser, the crystal was quantitatively converted to the metastable LIESST state at 10 K; its lattice parameters were measured up to 50 K, at which point the LIESST state begins to decay on a minute timescale. The change of the lattice parameters can be interpreted by a superposition of a normal temperature dependence, for which the isostructural zinc compound served as a reference, and an almost temperature‐independent part which is proportional to the fraction of molecules in the HS state.