Enhanced dielectricity coupled to spin-crossover in a one-dimensional polymer iron(ii) incorporating tetrathiafulvalene. Issue 24 (8th June 2020)

• Record Type: Journal Article
• Authors: Qiu, Ya-Ru; Cui, Long; Cai, Pei-Yu; Yu, Fei; Kurmoo, Mohamedally; Leong, Chanel F.; D'Alessandro, Deanna M.; Zuo, Jing-Lin
• Is Part Of: Chemical science. Volume 11:Issue 24(2020)
• Page Start: 6229
• Page End: 6235
• Publication Date: 2020-06-08
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc02388d
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A concerted bending–flattening motion of the redox-active TTF within constructed one-dimensional Fe II –TTF–Schiff-base chain with bridging 4, 4′-bpy enhances the dielectric constant coupled to its spin-crossover transition above room temperature. 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, [Fe II (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 Fe II 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.