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Hierarchical Frameworks of Metal–Organic Cages with Axial Ferroelectric Anisotropy
Author(s) -
Yadav Ashok,
Kulkarni Priyangi,
Praveenkumar Balu,
Steiner Alexander,
Boomishankar Ramamoorthy
Publication year - 2018
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.201803863
Subject(s) - ferroelectricity , counterion , anisotropy , materials science , dipole , chemical physics , crystallography , metal , tetragonal crystal system , ligand (biochemistry) , ion , dielectric , crystal structure , chemistry , optics , optoelectronics , physics , organic chemistry , biochemistry , receptor , metallurgy
Designing molecular crystals with switchable dipoles for ferroelectric applications is challenging and often serendipitous. Herein, we show a systematic approach toward hierarchical 1D, 2D and 3D frameworks that are assembled through successive linkage of metal–organic cages [Cu 6 (H 2 O) 12 (TPTA) 8 ] 12+ with chloride ions. Their ferroelectric properties are due to the displacement of channel‐bound nitrate counterions and solvated water molecules relative to the framework of cages. Ferroelectric measurements of crystals of discrete and 1D‐framework assemblies showed axial ferroelectric anisotropy with high remnant polarisation. Both, the reversible formation of cage‐connected networks and the observation of ferroelectric anisotropic behaviour are rare among metal–ligand cage assemblies.