TY - JOUR
T1 - Manipulation of the molecular spin crossover transition of Fe(H2B(pz)2)2(bipy) by addition of polar molecules
AU - Costa, Paulo S.
AU - Hao, Guanhua
AU - N'Diaye, Alpha T.
AU - Routaboul, Lucie
AU - Braunstein, Pierre
AU - Zhang, Xin
AU - Zhang, Jian
AU - Ekanayaka, Thilini K.
AU - Shi, Qin Yin
AU - Schlegel, Vicki
AU - Doudin, Bernard
AU - Enders, Axel
AU - Dowben, P. A.
N1 - Publisher Copyright:
© 2019 IOP Publishing Ltd.
PY - 2020
Y1 - 2020
N2 - The addition of various dipolar molecules is shown to affect the temperature dependence of the spin state occupancy of the much studied spin crossover Fe(II) complex, [Fe{H2B(pz)2}2(bipy)] (pz = pyrazol-1-yl, bipy = 2,2′-bipyridine). Specifically, the addition of benzimidazole results in a re-entrant spin crossover transition, i.e. the spin state starts in the mostly low spin state, then high spin state occupancy increases, and finally the high spin state occupancy decreases with increasing temperature. This behavior contrasts with that observed when the highly polar p -benzoquinonemonoimine zwitterion C6H2(..NH2)2(..O)2 was mixed with [Fe{H2B(pz)2}2(bipy)], which resulted in locking [Fe{H2B(pz)2}2(bipy)] largely into a low spin state while addition of the ethyl derivative C6H2(..NHC2H5)2(..O)2 did not appear to perturb the spin crossover transition of [Fe{H2B(pz)2}2(bipy)].
AB - The addition of various dipolar molecules is shown to affect the temperature dependence of the spin state occupancy of the much studied spin crossover Fe(II) complex, [Fe{H2B(pz)2}2(bipy)] (pz = pyrazol-1-yl, bipy = 2,2′-bipyridine). Specifically, the addition of benzimidazole results in a re-entrant spin crossover transition, i.e. the spin state starts in the mostly low spin state, then high spin state occupancy increases, and finally the high spin state occupancy decreases with increasing temperature. This behavior contrasts with that observed when the highly polar p -benzoquinonemonoimine zwitterion C6H2(..NH2)2(..O)2 was mixed with [Fe{H2B(pz)2}2(bipy)], which resulted in locking [Fe{H2B(pz)2}2(bipy)] largely into a low spin state while addition of the ethyl derivative C6H2(..NHC2H5)2(..O)2 did not appear to perturb the spin crossover transition of [Fe{H2B(pz)2}2(bipy)].
KW - X-ray absorption spectroscopy
KW - dipolar heteromolecular molecular interactions
KW - re-entrant transition
KW - spin crossover metal organic molecules
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U2 - 10.1088/1361-648X/ab468c
DO - 10.1088/1361-648X/ab468c
M3 - Article
C2 - 31639105
AN - SCOPUS:85075813185
VL - 32
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 3
M1 - 034001
ER -