Ferroelectric metallomesogens composed of achiral spin crossover molecules

Akiyoshi, Ryohei; Hirota, Yuma; Kosumi, Daisuke; Tsutsumi, Mayu; Nakamura, Masaaki; Lindoy, Leonard F.; Hayami, Shinya

doi:10.1039/c9sc01229j

Cited by 37 publications

(28 citation statements)

References 53 publications

(28 reference statements)

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“…The molecular length calculated by the time‐dependent density functional theory (TD‐DFT) for Pt‐L 1 16 is 29 Å (Supporting Information, Figure S10), which is commensurate with that estimated from X‐ray diffraction (28.8 Å), indicating that the mesophases belong to a non‐tilted lamellar phase. Combined with the characteristics of three high‐order diffraction peaks in a small‐angle range, we assume that there are intercalated structures in LCs phase [46–48] . Two molecules pack antiparallelly to form a tail‐to‐tail dimer, the rigid metalloaromatic units form the layers and the peripheral phenoxyalkyl chains are disorderly distributed between the layers.…”

Section: Figurementioning

confidence: 99%

Biased Symmetry Breaking and Chiral Control by Self‐Replicating in Achiral Tetradentate Platinum (II) Complexes

et al. 2021

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Obtaining homochirality from biased symmetry‐breaking of self‐assembly in achiral molecules remains a great challenge due to the lack of ingenious strategies and controlling their handedness. Here, we report the first case of biased symmetry breaking from achiral platinum (II) liquid crystals which self‐organize into an enantiomerically enriched single domain without selection of handedness in twist grain boundary TGB [*] phase. Most importantly, the chiral control of self‐organization can be achieved by using above the homochiral liquid crystal films with determined handedness (P or M) as a template. Moreover, benefiting from self‐assembled superhelix, these complexes exhibit prominent circularly polarized luminescence with high |glum| up to 3.4×10−3 in the TGB [*] mesophase. This work paves a neoteric avenue for the development of chiral self‐assemblies from achiral molecules.

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Section: Figurementioning

confidence: 99%

Biased Symmetry Breaking and Chiral Control by Self‐Replicating in Achiral Tetradentate Platinum (II) Complexes

et al. 2021

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“…Magnetic switching accompanied by nonpolar-polar structural transition has been observed for several compounds. 28,29,34,54,55 However, ferroelectricity accompanied by magnetic switching in a single-phase molecular material remains to be demonstrated. In the compound prepared in this study, the ferroelectric phase transition as actuated by the motion of sulfate anions is due to a minute structural change in the Co(II) complex cations.…”

Section: Mechanism Discussionmentioning

confidence: 99%

“…Consequently, the development of molecular materials that exhibit correlated magnetic switching and ferroelectric properties is highly desired. [28][29][30][31][32][33][34] Our previous study on single-crystal [Co II (en) 3 ](ox) (en = ethylenediamine; ox 2− = oxalate dianions) revealed that the unquenched orbital angular momentum of [Co II (en) 3 ] 2+ cations is highly susceptible to minor changes in coordination configuration. 35 In this compound, the order-disorder phase transition of ox 2− dianions in cavities encapsulated by five complex cations is reminiscent of the perovskite compounds that exhibit ferroelectric properties, which are derived from the polarization of dynamic molecular cations in their frameworks.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Crystal Shows Multiple Correlated Magnetic and Ferroelectric Switchings

Wang

et al. 2021

CCS Chem

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Simultaneous control of the magnetic and electric properties of materials is crucial for their application in next-generation memory and sensor devices. Herein, we report a single-crystal Co(II) complex that exhibits unprecedented two-step magnetic switching accompanied by paraelectric-ferroelectric-paraelectric phase transition. The ferroelectricity of the material is governed by changes in the directionality of the sulfate dianions therein that trigger nonpolarpolar-nonpolar variation of the crystal symmetry and induce slight structural changes in the Co(II) complex. The unquenched orbital angular momentum of the Co(II) ion, which has trigonal antiprismatic coordination geometry, is susceptible to the coordination environment. Accordingly, two-step magnetic switching accompanied by ferroelectric phase transitions is demonstrated, and the detailed mechanism of the paraelectric-ferroelectric-paraelectric phase transitions and the consequent magnetic switching are investigated. Thus, this study presents a unique multifunctional material as well as a viable strategy for the development of superior molecular magnetoelectric materials.

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“…Molecular functional materials exhibiting both SCO behavior and ferroelectric property are of significant interest because of the potential that resulting magnetoelectric (ME) effects might be anticipated. However, to the best of our knowledge, there is a general lack of reports concerned with the synthesis and investigation of such ferroelectric SCO compounds [4f, 8] . Recently in a solid‐state SCO ferroelectric study it was shown that a hydrated iron(II) complex of type [Fe(bpp) 2 ](isonic) 2 ⋅2H 2 O (bpp=2,6‐bis‐(pyrazol‐3‐yl)pyridine; isonic=isonicotinate) was driven by structural transformation from a non‐polar to polar space group through the removal of water [8] .…”

Section: Methodsmentioning

confidence: 99%

Ferroelectric and Spin Crossover Behavior in a Cobalt(II) Compound Induced by Polar‐Ligand‐Substituent Motion

et al. 2021

Self Cite

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Ferroelectric spin crossover (SCO) behavior is demonstrated to occur in the cobalt(II) complex, [Co(FPhterpy) 2 ](BPh 4 ) 2 •3ac (1•3 ac; FPh-terpy = 4'-((3-fluorophenyl)ethynyl)-2,2':6',2''-terpyridine) and is dependent on the degree of 1808 flip-flop motion of the ligands polar fluorophenyl ring. Single crystal X-ray structures at several temperatures confirmed the flip-flop motion of fluorobenzene ring and also gave evidence for the SCO behavior with the latter behavior also confirmed by magnetic susceptibility measurements. The molecular motion of the fluorobenzene ring was also revealed using solid-state 19 F NMR spectroscopy. Thus the SCO behavior is accompanied by the flip-flop motion of the fluorobenzene ring, leading to destabilization of the low spin cobalt(II) state; with the magnitude of rotation able to be controlled by an electric field. This first example of spin-state conversion being dependent on the molecular motion of a ligand-appended fluorobenzene ring in a SCO cobalt(II) compound provides new insight for the design of a new category of molecule-based magnetoelectric materials.

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Ferroelectric metallomesogens composed of achiral spin crossover molecules

Abstract: We report for the first time ferroelectricity induced by spin transition associated with a crystal – liquid crystal phase transition in achiral spin crossover molecules.

Cited by 37 publications

References 53 publications

Biased Symmetry Breaking and Chiral Control by Self‐Replicating in Achiral Tetradentate Platinum (II) Complexes

Biased Symmetry Breaking and Chiral Control by Self‐Replicating in Achiral Tetradentate Platinum (II) Complexes

A Molecular Crystal Shows Multiple Correlated Magnetic and Ferroelectric Switchings

Ferroelectric and Spin Crossover Behavior in a Cobalt(II) Compound Induced by Polar‐Ligand‐Substituent Motion

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