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Spin‐Crossover and Field‐Induced Single‐Molecule Magnet Behaviour in Metal(II)‐Dipyrazolylpyridine Complexes
Author(s) -
Douib Haiet,
Cornet Louis,
Gonzalez Jessica Flores,
Trzop Elzbieta,
Dorcet Vincent,
Gouasmia Abdelkrim,
Ouahab Lahcène,
Cador Olivier,
Pointillart Fabrice
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800819
Subject(s) - chemistry , spin crossover , spin transition , crystallography , single molecule magnet , magnet , atmospheric temperature range , condensed matter physics , magnetic field , magnetization , thermodynamics , physics , quantum mechanics
The reaction between the 2,6‐di(pyrazol‐1‐yl)‐4‐(bromomethyl)pyridine ( L ) ligand and divalent transition metal salts led to the formation of three mononuclear complexes of formula [M( L ) 2 ](BF 4 ) 2 · x MeNO 2 [M = Fe II ( 1· x MeNO 2 ), x = 0 and 4, M = Co II , x = 2 ( 2·2MeNO 2 ) and]. Static magnetic measurements highlighted thermal spin crossover at high temperature (320–340 K) for the two Fe II solvatomorphs nevertheless both the solvation degree and crystal packing had drastic influence on the shape and width of the hysteresis loop. Thus the 1 displayed abrupt and straight (6 K) hysteresis loop while for 1·4MeNO 2 the thermal spin transition could be described as a six‐step gradual transition with the widest magnetic bistability range (35 K) for this kind of complexes. Irradiation at 530 nm of 1·4MeNO 2 provoked an efficient LIESST effect at low temperature (T LIESST = 55 K). Finally dynamic magnetic measurements of 2·2MeNO 2 shown a field‐induced mononuclear Single‐Molecule Magnet behavior with Δ = 14.6(4) cm –1 and τ 0 = 6.28(8) × 10 –7 s.