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Updated: Dec 8, 2025
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Enhanced dielectricity coupled to spin-crossover in a one-dimensional polymer iron(ii) incorporating
Ya-Ru Qiu1, Long Cui1, Pei-Yu Cai1
1State Key Laboratory of Coordination Chemistry , School of Chemistry and Chemical Engineering , Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210023 , P. R. China .
Abstract:
In designing multifunctional materials for potential switches that can be used as memory devices, the high-spin (HS) to low-spin (LS) crossover (SCO) one-dimensional polymer, [FeII(L)(4,4'-bpy)] n , was constructed from a designed redox-active tetrathiafulvalene (TTF) functionalized Schiff-base and the ditopic linker 4,4'-bipyridine (bpy). It exhibits an 8 K hysteretic SCO centred at T 1/2 = 325 K which is coupled to changes in its dielectric constant. The crystal structures above and below the transition temperature reveal similar parallel linear ···Fe-bpy-Fe-bpy··· chains displaying expansion of the FeII octahedron in the HS state. Density functional theory (DFT) calculations reveal a concerted electronic charge and spin change represented by the Mülliken charge of the Fe and the magnitude and direction of the dipole moment which substantiate the experimental observations.
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