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A Ferroelectric Iron(II) Spin Crossover Material
Author(s) -
JornetMollá Verónica,
Duan Yan,
GiménezSaiz Carlos,
Tang YuanYuan,
Li PengFei,
Romero Francisco M.,
Xiong RenGen
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201707401
Subject(s) - acentric factor , spin crossover , crystallography , monoclinic crystal system , ferroelectricity , chemistry , pyridine , hydrogen bond , crystal structure , crystal (programming language) , materials science , molecule , organic chemistry , dielectric , optoelectronics , computer science , programming language
A dual‐function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well‐known iron(II) spin crossover complex [Fe(bpp) 2 ] 2+ (bpp=2,6‐bis(pyrazol‐3‐yl)pyridine), a four‐fold noncentrosymmetric H‐bond donor, was combined with a disymmetric H‐bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp) 2 ](isonic) 2 ⋅2 H 2 O. This low‐spin iron(II) compound crystallizes in the acentric nonpolar I 4 ‾ space group and shows piezoelectricity and SHG properties. Upon dehydration, it undergoes a single‐crystal to single‐crystal structural rearrangement to a monoclinic polar Pc phase that is ferroelectric and exhibits spin crossover.