Preparation, Structure, and Redox Behavior of Bis(diarylmethylene)dihydrothiophene and Its π‑Extended Analogues

The preparation, X-ray structure, and optoelectronic properties of bis­(diarylmethylene)­dihydrothiophene <b>1</b> and its π-extended analogues <b>2</b> are described. The development of a simple, short-step synthetic route allowed us to prepare derivatives with different aryl units. X-ray crystallographic analysis of <b>1b</b> and <b>2b</b> revealed their quinoidal structures, which exhibit strong electronic absorption in the visible region. Cyclic voltammetry measurements revealed their strong electron-donating properties. <b>1b</b> showed two-step electrochromic behavior between the corresponding radical cation and dication

Preparation, Structure, and Redox Behavior of Bis(diarylmethylene)dihydrothiophene and Its π‑Extended Analogues

The preparation, X-ray structure, and optoelectronic properties of bis­(diarylmethylene)­dihydrothiophene <b>1</b> and its π-extended analogues <b>2</b> are described. The development of a simple, short-step synthetic route allowed us to prepare derivatives with different aryl units. X-ray crystallographic analysis of <b>1b</b> and <b>2b</b> revealed their quinoidal structures, which exhibit strong electronic absorption in the visible region. Cyclic voltammetry measurements revealed their strong electron-donating properties. <b>1b</b> showed two-step electrochromic behavior between the corresponding radical cation and dication

Thermosalient Effect of 5‑Fluorobenzoyl-4-(4-methoxyphenyl)ethynyl-1-methylimidazole without Phase Transition

5‑Fluorobenzoyl-4-(4-methoxyphenyl)ethynyl-1-methylimidazole 1 exhibited a thermosalient effect without phase transition. The crystal of 1 was jumped by heating to about 80 °C using a hot plate. No phase transition peak was observed at this temperature range according to DSC measurement, unlike renowned thermosalient crystals. Variable-temperature X-ray crystal structure analyses revealed that anisotropical cell constant expansion resulting from the torsion angle change between the imidazole group and carbonyl moiety induced unit cell constant expansion and the thermosalient effect

Thermosalient Effect of 5‑Fluorobenzoyl-4-(4-methoxyphenyl)ethynyl-1-methylimidazole without Phase Transition

5‑Fluorobenzoyl-4-(4-methoxyphenyl)ethynyl-1-methylimidazole 1 exhibited a thermosalient effect without phase transition. The crystal of 1 was jumped by heating to about 80 °C using a hot plate. No phase transition peak was observed at this temperature range according to DSC measurement, unlike renowned thermosalient crystals. Variable-temperature X-ray crystal structure analyses revealed that anisotropical cell constant expansion resulting from the torsion angle change between the imidazole group and carbonyl moiety induced unit cell constant expansion and the thermosalient effect

Protonic Conductivity and Hydrogen Bonds in (Haloanilinium)(H₂PO₄) Crystals

Brønsted acid–base reactions between phosphoric acid (H₃PO₄) and haloanilines in alcohols formed 1:1 proton-transferred ionic salts of (X-anilinium⁺)­(H₂PO₄^–) and 2:1 ones of (X-anilinium⁺)₂(HPO₄^2–) (X = F, Cl, Br, and I at o, m, and p positions of anilinium). Only the former 1:1 single crystals showed proton conductivity under the N₂ condition, and the latter 2:1 crystals became protonic insulators. In crystals, diverse hydrogen-bonding structures from 1D to 2D networks were achieved by modification of the molecular structure of X-anilinium cations. The protonic conductivity was associated with the connectivity of H₂PO₄^– anions in the hydrogen-bonding networks. The hydrogen-bonding ladder chains in (<i>o</i>-cloroanilinim)­(H₂PO₄^–) and (<i>o</i>-bromoanilinim)­(H₂PO₄^–) resulted in the highest protonic conductivity of ∼10^–3 S cm^–1. The protonic conductivity of the ladder-chain (H₂PO₄^–) arrangements was higher than that of 2D sheets. The motional freedom of protons was analyzed by difference Fourier analysis of the single-crystal X-ray structure. The 2D layer, including (H₂PO₄^–)₂ dimers and (H₂PO₄^–)₄ tetramers, showed relatively low protonic conductivity, and the activation energy for proton conductivity was lowered by increasing the hydrogen-bonding connectivity and uniformity between H₂PO₄^– anions

Collective In-Plane Molecular Rotator Based on Dibromoiodomesitylene π‑Stacks

Interest in artificial solid-state molecular rotator systems is growing as they enable systems to be designed for achieving specific physical functions. The phase transition behavior of four halomesitylene crystals indicated dynamic in-plane molecular rotator characteristics in dibromoiodomesitylene, tribromomesitylene, and dibromomesitylene crystals. Such molecular rotation in diiodomesitylene crystals was suppressed by effective I···I intermolecular interactions. The in-plane molecular rotation accompanied by a change in dipole moment resulted in dielectric phase transitions in polar dibromoiodomesitylene and dibromomesitylene crystals. No dielectric anomaly was observed for the in-plane molecular rotation of tribromomesitylene in the absence of this dipole moment change. Typical antiferroelectric–paraelectric phase transitions were observed in the dibromomesitylene crystal, whereas the dielectric anomaly of dibromoiodomesitylene crystals was associated with the collective in-plane molecular rotation of polar π-molecules in the π-stack. We found that the single-rope-like collective in-plane molecular rotator was dominated by intermolecular I···I interactions along the π-stacking column of polar dibromoiodomesitylene

Carrier Concentration Dependent Conduction in Insulator-Doped Donor/Acceptor Chain Compounds

On the basis of the concept that the design of a mixed valence system is a key route to create electronic conducting frameworks, we propose a unique idea to rationally produce mixed valency in an ionic donor/acceptor chain (i.e., D⁺A^– chain). The doping of a redox-inert (insulator) dopant (P) into a D⁺A^– chain in place of neutral D enables the creation of mixed valency A⁰/A^– domains between P units: P–(D⁺A^–)_<i>n</i>A⁰–P, where <i>n</i> is directly dependent on the dopant ratio, and charge transfer through the P units leads to electron transport along the framework. This hypothesis was experimentally demonstrated in an ionic DA chain synthesized from a redox-active paddlewheel [Ru₂^II,II] complex and TCNQ derivative by doping with a redox-inert [Rh₂^II,II] complex

Carrier Concentration Dependent Conduction in Insulator-Doped Donor/Acceptor Chain Compounds

On the basis of the concept that the design of a mixed valence system is a key route to create electronic conducting frameworks, we propose a unique idea to rationally produce mixed valency in an ionic donor/acceptor chain (i.e., D⁺A^– chain). The doping of a redox-inert (insulator) dopant (P) into a D⁺A^– chain in place of neutral D enables the creation of mixed valency A⁰/A^– domains between P units: P–(D⁺A^–)_<i>n</i>A⁰–P, where <i>n</i> is directly dependent on the dopant ratio, and charge transfer through the P units leads to electron transport along the framework. This hypothesis was experimentally demonstrated in an ionic DA chain synthesized from a redox-active paddlewheel [Ru₂^II,II] complex and TCNQ derivative by doping with a redox-inert [Rh₂^II,II] complex

Carrier Concentration Dependent Conduction in Insulator-Doped Donor/Acceptor Chain Compounds

On the basis of the concept that the design of a mixed valence system is a key route to create electronic conducting frameworks, we propose a unique idea to rationally produce mixed valency in an ionic donor/acceptor chain (i.e., D⁺A^– chain). The doping of a redox-inert (insulator) dopant (P) into a D⁺A^– chain in place of neutral D enables the creation of mixed valency A⁰/A^– domains between P units: P–(D⁺A^–)_<i>n</i>A⁰–P, where <i>n</i> is directly dependent on the dopant ratio, and charge transfer through the P units leads to electron transport along the framework. This hypothesis was experimentally demonstrated in an ionic DA chain synthesized from a redox-active paddlewheel [Ru₂^II,II] complex and TCNQ derivative by doping with a redox-inert [Rh₂^II,II] complex

Carrier Concentration Dependent Conduction in Insulator-Doped Donor/Acceptor Chain Compounds

On the basis of the concept that the design of a mixed valence system is a key route to create electronic conducting frameworks, we propose a unique idea to rationally produce mixed valency in an ionic donor/acceptor chain (i.e., D⁺A^– chain). The doping of a redox-inert (insulator) dopant (P) into a D⁺A^– chain in place of neutral D enables the creation of mixed valency A⁰/A^– domains between P units: P–(D⁺A^–)_<i>n</i>A⁰–P, where <i>n</i> is directly dependent on the dopant ratio, and charge transfer through the P units leads to electron transport along the framework. This hypothesis was experimentally demonstrated in an ionic DA chain synthesized from a redox-active paddlewheel [Ru₂^II,II] complex and TCNQ derivative by doping with a redox-inert [Rh₂^II,II] complex