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An Investigation of Photo‐ and Pressure‐Induced Effects in a Pair of Isostructural Two‐Dimensional Spin‐Crossover Framework Materials
Author(s) -
Sciortino Natasha F.,
Neville Suzanne M.,
Desplanches Cédric,
Létard JeanFrançois,
Martinez Victor,
Real José Antonio,
Moubaraki Boujemaa,
Murray Keith S.,
Kepert Cameron J.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201400367
Subject(s) - isostructural , spin crossover , spin transition , metastability , excited state , trapping , chemistry , crystallography , spin states , atmospheric temperature range , materials science , condensed matter physics , atomic physics , crystal structure , thermodynamics , inorganic chemistry , physics , ecology , organic chemistry , biology
Two new isostructural iron(II) spin‐crossover (SCO) framework (SCOF) materials of the type [Fe(dpms) 2 (NCX) 2 ] (dpms=4,4′‐dipyridylmethyl sulfide; X=S ( SCOF‐6(S) ), X=Se ( SCOF‐6(Se) )) have been synthesized. The 2D framework materials consist of undulating and interpenetrated rhomboid (4,4) nets. SCOF‐6(S) displays an incomplete SCO transition with only approximately 30 % conversion of high‐spin (HS) to low‐spin iron(II) sites over the temperature range 300–4 K ( T 1/2 =75 K). In contrast, the NCSe − analogue, SCOF‐6(Se) , displays a complete SCO transition ( T 1/2 =135 K). Photomagnetic characterizations reveal quantitative light‐ induced excited spin‐state trapping (LIESST) of metastable HS iron(II) sites at 10 K. The temperature at which the photoinduced stored information is erased is 58 and 50 K for SCOF‐6(S) and SCOF‐6(Se) , respectively. Variable‐pressure magnetic measurements were performed on SCOF‐6(S) , revealing that with increasing pressure both the T 1/2 value and the extent of spin conversion are increased; with pressures exceeding 5.2 kbar a complete thermal transition is achieved. This study confirms that kinetic trapping effects are responsible for hindering a complete thermally induced spin transition in SCOF‐6(S) at ambient pressure due to an interplay between close T 1/2 and T (LIESST) values.