Solvent vapor-induced polarity and ferroelectricity switching

Abstract

A new example of vapor-induced reversible polarity and ferroelectricity switching system has been demonstrated in mononuclear iron(iii) complexes.

Polarity and Dielectric Property Control Triggered by a Coordinated Solvent Molecule Exchange in Luminescent Mononuclear Aluminium(III) Complexes

“…These observed PXRD patterns correspond to the pattern for [Fe(sap)(acac)(DMSO)] which was reported previously by us. [9] This result is in accordance with the replacement of the coordinated solvent by the DMSO upon exposure to DMSO vapour, resulting in structural rearrangements to the polar (Cc) structure. Notably, although the crystals were opacified, their crystal shape remained (Figure S7).…”

“…The structure of 1 was found to be similar to the previously reported structure of the iron(III) complex [Fe(sap)(acac)(MeOH)] (Figure S1). [9] The aluminium(III) centre has a NO 5 -donor coordination sphere with a distorted octahedral geometry. The metal centre has a coordinated NO 3 donor set equatorially arising from the H 2 sap and acac ligands, while the axial positions are occupied by O and O' donors form acac and MeOH, respectively.…”

“…In our previous study, we demonstrated that mononuclear iron(III) complexes of type [Fe(sap)(acac)(sol)] (H 2 sap = 2-salicylideneaminophenol; acac = acetylacetonate and sol = MeOH, DMSO, pyridine), incorporating a substitution-prone coordination site, could switch ferroelectric behaviour and polarity, which was attributed to the structural transformations triggered by exposure to solvent vapour. [9] This involved the use of [Fe(sap)(acac)(DMSO)], which belongs to the SHG-active polar Cc space group. The study provided a novel example of vapourinduced reversible ferroelectric switching systems, wherein coordinated solvent substitution was the "trigger" for the corresponding structural rearrangements.…”

Vapor-Induced Conversion of a Centrosymmetric Organic–Inorganic Hybrid Crystal into a Proton-Conducting Second-Harmonic-Generation-Active Material

“…Chemical-responsive materials have attracted much attention due to their switchable physical properties. However, in contrast with the extensive research efforts that have been devoted to the synthesis of materials exhibiting switchable luminescent − and magnetic properties, − polarity-switchable materials are still limited. − Polar materials with noncentrosymmetric structures show ferroelectric and second-harmonic-generation (SHG) properties, which are important in memory and nonlinear optical devices. − More recently, multifunctional polar materials have been developed by realizing proton conduction and magnetic properties in noncentrosymmetric structures. However, switching the polarity of materials, that is, the SHG properties, under chemical stimuli remains largely challenging due to the difficulty in chemically controlling the breaking inversion symmetry of the crystal structure.…”

Ferroelectric coordination metal complexes based on structural and electron dynamics

“…6a). 90 [Fe(sap)(acac)(MeOH)] crystallized in the triclinic (centrosymmetric) space group. Each iron( iii ) centre has a distorted octahedral geometry being coordinated equatorially by a doubly deprotonated H 2 sap ligand and one oxygen from a deprotonated Hacac ligand, while one axial position is occupied by an O donor from MeOH, while the second axial site is occupied by the remaining oxygen of the deprotonated Hacac ligand.…”