Premium
A Spin Transition Molecular Material with a Wide Bistability Domain
Author(s) -
Garcia Yann,
Moscovici Jacques,
Michalowicz Alain,
Ksenofontov Vadim,
Levchenko Georg,
Bravic Georges,
Chasseau Daniel,
Gütlich Philipp
Publication year - 2002
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 - 10.1002/1521-3765(20021104)8:21<4992::aid-chem4992>3.0.co;2-8
Subject(s) - extended x ray absorption fine structure , spin crossover , spin transition , hysteresis , bistability , spectroscopy , materials science , cooperativity , thermal hysteresis , chemistry , crystallography , condensed matter physics , absorption spectroscopy , phase transition , physics , optics , biochemistry , optoelectronics , quantum mechanics
[Fe(hyptrz) 3 ](4‐chloro‐3‐nitrophenylsulfonate) 2 ⋅ 2 H 2 O ( 1 ; hyptrz=4‐(3′‐hydroxypropyl)‐1,2,4‐triazole) has been synthesized and its physical properties have been investigated by several physical techniques including magnetic susceptibility measurements, calorimetry, and Mössbauer, optical, and EXAFS spectroscopy. Compound 1 exhibits a spin transition below room temperature, together with a very wide thermal hysteresis of about 50 K. This represents the widest hysteresis loop ever observed for an Fe II ‐1,2,4‐triazole spin transition material. The cooperativity is discussed on the basis of temperature‐dependent EXAFS studies and of the structural features of a Cu II analogue. The EXAFS structural model of ( 1 ) in both spin states is compared to that obtained for a related material whose spin transition occurs above room temperature. EXAFS spectroscopy suggests that 1,2,4‐triazole chain compounds retain a linear character whatever the spin state of the iron( II ).