Metallo-Supramolecular Polymers: Design, Function, and Device Application

Higuchi, Masayoshi

doi:10.1007/978-4-431-56429-4_12

Cited by 6 publications

(7 citation statements)

References 60 publications

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“…MSPs 22,23 with metal ions and multitopic organic ligands, such as bis-terpyridine, have been recently reported as the fourth generation of EC materials, following the first (metal oxides, e.g., tungsten oxide), second (transition metal complexes, e.g., Prussian blue), and third (π-conjugated polymers, e.g., PEDOT and PANI) generation of the EC materials. 34−41 MSPs demonstrate absorption in the visible region because of the metal-to-ligand charge transfer (MLCT, d → π*) from the metal ion center to the organic ligand.…”

Section: ■ Introductionmentioning

confidence: 99%

Electrochromic Ru-Based Metallo-Supramolecular Polymer with a Layered Inorganic−Organic Hybrid Nanocomposite for Improved Electrochemical Properties

Fujii,

Santra,

Bera

et al. 2023

ACS Appl. Polym. Mater.

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Herein, we report improving the electrochromic (EC) properties of metallo-supramolecular polymers (MSPs) via forming nanocomposite with a layered inorganic-imidazoline covalently bonded hybrid (LIIm). Polymer-based nanocomposites exhibit improvements in mechanical, optical, gas barrier properties, etc. Clay minerals and organoclays are beneficial additives in synthesizing nanocomposites. However, only a few investigations of their EC properties have been reported. We have prepared the nanocomposites of Ru(II)-based metallo-supramolecular polymer (polyRu) and LIIm by mixing them in various polyRu/LIIm ratios in methanol. Then, the EC properties and structural features of the resulting red nanocomposites (polyRu−LIIm composites) were analyzed. The polyRu− LIIm composites exhibited strong metal-to-ligand charge transfer (MLCT) absorptions at ∼530 nm with a slight red shift (4−7 nm) than that of pristine polyRu. The MLCT absorptions of polyRu−LIIm composites were more intense than that of polyRu. Spin-coated polyRu−LIIm composite films showed a reversible pair of redox waves at half-wave potentials (E 1/2 ) of 0.9 V in cyclic voltammetry (CV) curves and reversible EC changes between red and pale green caused by the redox of Ru(II/III) upon applied potential. The E 1/2 and peak currents do not drastically change compared to those of polyRu. Furthermore, the composite thin films exhibited coloration efficiencies (CE) of 640−810 cm 2 /C higher than the 597 cm 2 /C of polyRu. The high optical contrasts (ΔT) of >70% and fast switching times were maintained. Scanning electron microscopy (SEM)−energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses revealed the characteristic structural features of polyRu−LIIm composites where polyRu-coated LIIm forms agglomerate (200 nm−10 μm), which varied with the polyRu/LIIm ratios. Furthermore, the EC memory times were improved to 26 min for one of the polyRu−LIIm composites from 170 s of polyRu.

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Section: ■ Introductionmentioning

confidence: 99%

Electrochromic Ru-Based Metallo-Supramolecular Polymer with a Layered Inorganic−Organic Hybrid Nanocomposite for Improved Electrochemical Properties

Fujii,

Santra,

Bera

et al. 2023

ACS Appl. Polym. Mater.

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“…, absorbance or transmittance changes in the visible spectrum) by applying an external voltage is defined as electrochromism . Some electrochromic (EC) materials are utilized in various technological aspects such as smart windows, − displays, − antiglare mirrors, − and adaptive camouflages. − Diverse EC materials have been reported so far, including organic conducting polymers, − redox-active organic small molecules, − metal oxides, − transition metal–organic complexes, − and metallo-supramolecular polymers (MSPs). − MSPs are recently developed EC materials with an intense metal-to-ligand charge transfer (MLCT) band in the visible region. The MLCT band gap depends on the electronic state of the d orbital in the metal and the π-conjugated structure of the ligand. − MSPs are synthesized from various metal ions and ditopic ligands, which have two metal-coordination sites.…”

Section: Introductionmentioning

confidence: 99%

Ru(II)-Based Metallo-Supramolecular Polymer with Tetrakis(N-methylbenzimidazolyl)bipyridine for a Durable, Nonvolatile, and Electrochromic Device Driven at 0.6 V

Santra

Mondal

Yoshida

et al. 2021

ACS Appl. Mater. Interfaces

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Low-voltage operation, high durability, and long memory time are demanded for electrochromic (EC) display device applications. Metallo-supramolecular polymers (MSPs), composed of a metal ion and ditopic ligand, are one of the recently developed EC materials, and the ligand modification is expected to tune the redox potential of MSP. In order to lower the redox potential of MSP, tetrakis(N-methylbenzimidazolyl)bipyridine (L Bip ) was designed as an electronically rich ligand. Ru-based MSP (polyRu-L Bip ) was successfully synthesized by 1:1 complexation of RuCl2(DMSO)4 with L Bip . The molecular weight (M w) was high (8.8 × 106 Da) enough to provide a simple 1H NMR spectrum, of which the proton peaks could be assigned by the comparison with the spectrum of the corresponding mono-Ru complex. The redox potential (E 1/2) between Ru(II/III) was 0.51 V versus Ag/Ag+, which was much lower than the redox potential of previously reported Ru-based MSP with bis(terpyridyl)benzene (0.95 V vs Ag/Ag+). The polymer film exhibited reversible, distinct color changes between violet and light green-yellow upon applying very low potentials of 0 and 0.6 V vs Ag/Ag+, respectively. The appearance and disappearance of the metal-to-ligand charge transfer absorption by the electrochemical redox between Ru(II/III) were confirmed using in situ spectro-electrochemical measurement. A solid-state EC device with polyRu-L Bip was revealed to have large optical contrast (ΔT 54%), fast response time (1.37 s for bleaching and 0.67 s for coloration), remarkable coloration efficiency (571 cm2/C), and high durability for the repeated color changes more than 20,000 cycles. The device also showed a long optical memory time of up to 19 h to maintain 40% to the initial contrast under the open circuit conditions. It is considered that the stabilization of the Ru(III) state by L Bip suppressed the self-coloring to Ru(II) inside the device.

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“…1−8 Metal centers in MSPs supply unique optical, electrochemical, photochemical, magnetic, and catalytic properties, which organic polymers cannot provide. 3,9,10 An MSP is obtained by the 1:1 complexation between a metal ion and a ditopic ligand. A linear MSP is prepared using the linear and rigid ligand, and a macrocyclic MSP tends to be formed when the bent or flexible ligand is used.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Metallo-supramolecular polymers (MSPs) have engrossed huge considerations of polymer/inorganic chemists owing to the wide potential applications including sensors, memories, rectifier diodes, light emitting and photovoltaic devices, electrochromic displays, nanolithography, redox-tunable photonic crystals, stimulus-responsive materials, drug delivery and release systems, and molecular motors. − Metal centers in MSPs supply unique optical, electrochemical, photochemical, magnetic, and catalytic properties, which organic polymers cannot provide. ,, An MSP is obtained by the 1:1 complexation between a metal ion and a ditopic ligand. A linear MSP is prepared using the linear and rigid ligand, and a macrocyclic MSP tends to be formed when the bent or flexible ligand is used.…”

Section: Introductionmentioning

confidence: 99%

Helical Fe(II)-Based Metallo-Supramolecular Polymers: Effect of Crown Ether Groups Located outside the Helix on Hydrous Proton Channel Formation

Chakraborty

Rana

Narayana

et al. 2020

ACS Appl. Polym. Mater.

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Helical Fe(II)-based metallo-supramolecular polymers with/without crown ether groups (polyFe-C and polyFe-H, respectively) were synthesized by the 1:1 complexation of an Fe(II) salt and chiral bisterpyridine ligands with/without 18-crown-6. The stoichiometric complexation of Fe(II) and the ligand was confirmed by the UV−vis spectral titration experiment. PolyFe-C and polyFe-H showed a similar molecular weight (9.2 × 10 4 and 9.83 × 10 4 Da, respectively) and metal-to-ligand charge transfer absorption at the same wavelength (572 nm) in solution. It was revealed by scanning electron microscopy that polyFe-C with the crown ether groups has a highly porous structure unlike polyFe-H. PolyFe-C showed about 50 times higher proton conductivity (3.0 × 10 −4 S cm −1 ) than polyFe-H (6.4 × 10 −6 S cm −1 ) at 95% RH and 25 °C. The conductivity of polyFe-C was enhanced up to 5.8 × 10 −3 S cm −1 with increasing temperature to 75 °C. The calculated activation energy (0.46 eV) suggested that proton transfer in polyFe-C at 95% RH occurred according to the mixed state of the Grotthuss and vehicle mechanisms. The Fourier transform infrared spectrum of polyFe-C unveiled the formation of [H + (H 2 O) n ]. It was concluded that hydronium stabilized by the crown ether groups aligned outside the helical polymer accelerated the incorporation of water molecules to the polymer under humid conditions and assisted the proton channel formation by [H + (H 2 O) n ] in the polymer.

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Metallo-Supramolecular Polymers: Design, Function, and Device Application

Cited by 6 publications

References 60 publications

Electrochromic Ru-Based Metallo-Supramolecular Polymer with a Layered Inorganic−Organic Hybrid Nanocomposite for Improved Electrochemical Properties

Electrochromic Ru-Based Metallo-Supramolecular Polymer with a Layered Inorganic−Organic Hybrid Nanocomposite for Improved Electrochemical Properties

Ru(II)-Based Metallo-Supramolecular Polymer with Tetrakis(N-methylbenzimidazolyl)bipyridine for a Durable, Nonvolatile, and Electrochromic Device Driven at 0.6 V

Helical Fe(II)-Based Metallo-Supramolecular Polymers: Effect of Crown Ether Groups Located outside the Helix on Hydrous Proton Channel Formation

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