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

Hydrophilic and Hydrophobic Channels of Flexible Crystal Lattice: (Guanidinium)₂(Benzene-1,4-disulfonate)·<i>n</i>(XC₆H₅)

The −NH2···[SO3–]– electrostatic hydrogen bonding interaction between guanidinium (G+) and benzene-1,4-disulfonate (BS2–) formed the two-dimensional hydrogen-bonding network linked by benzene pillars, which formed a host–guest crystal with a halobenzene derivative (XC6H5) as a guest. When X = F, the (G+)2(BS2–)·3(FC6H5) crystals were obtained in the same type as the benzene inclusion (G+)2(BS2–)·3(C6H6) crystals. On the contrary, the size of the guest molecule increases for X = Cl and Br, and a hydrophilic channel with nine H2O molecules and a hydrophobic channel with two XC6H5 molecules coexist in (G+)2(BS2–)·2(XC6H5)·9(H2O) crystals. The crystal structure with X = I returned to that of the crystals with FC6H5 as the guest, and the number of guest molecules decreased from three to two. Crystals with hydrophilic channels in a highly symmetric hexagonal lattice appear at X = Cl and Br, which are the boundary region between X = F and I. (G+)2(BS2–)·2(ClC6H5)·9(H2O) crystals changed to guest-free crystals by heat at 373 K, which showed only gate H2O adsorption–desorption behavior at 298 K. The original host–guest crystals were recovered by the vapor diffusion of the ClC6H5–H2O mixture. However, once the crystal is heated to 420 K, it changes to a different host crystal (G+)2(BS2–), where XC6H5 cannot be adsorbed again

Dynamic Motion of Twisted π System-Induced Temperature-Dependent Dielectric Response in the Neat Liquid State

Molecular assemblies of twisted π molecules of tetraphenylene with long alkoxy chains (1) and tetra­[2,3]­thienylene with long alkylamide chains (2) or long alkoxy chains (3) and their dielectric properties were investigated. Different degrees of intermolecular interaction of 1–3 afforded different molecular assemblies, including an ordered columnar structure, disordered columnar, and lamellar structures. The introduction of long alkyl chains enabled us to create thermally stable liquid crystalline or liquid states. Temperature-dependent dielectric measurement revealed that the dynamic flipping motion of the tetra­[2,3]­thienylene core of 3 induced a temperature- and frequency-dependent dielectric anomaly in the neat liquid phase. This flipping motion of the central tetra­[2,3]­thienylene π core occurred relatively easily in the liquid state with a high degree of freedom of molecular motion

Highly Proton-Conducting Mixed Proton-Transferred [(H₂PO₄^–)(H₃PO₄)]∞ Networks Supported by 2,2′-Diaminobithiazolium in Crystals

Hydrogen-bonding organic acid–base salts are promising candidates for the chemical design of high-performance anhydrous proton conductors. The simple molecular crystals between the π-planar molecules of 2,2′-diaminobithiazolium (DABT) derivative and hydrogen-bonding H3PO4 formed the proton-transferred salts with proton conductivities above ∼10–4 S cm–1 and anisotropic behavior. Controlling the crystallization condition facilitated the formation of binary salts between di-cationic H2DABT2+ and (H3PO4–)2 or mixed proton-transferred (H2PO4–)2(H3PO4)2 with different hydrogen-bonding networks, including one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) networks. The structural isomers of 2,2′-diamino-4,4′-bithiazolium (2,4-DABT) and 2,2′-diamino-5,5′-bithiazolium (2,5-DABT) formed a different type of packing structure even with the same crystal stoichiometry of (H2DABT2+)­(H2PO4–)2 and/or (H2DABT2+)­(H2PO4–)2(H3PO4)2 where the latter salt had different protonated species of H2PO4– and H3PO4 in the hydrogen-bonding network. Four and 10 protons per H2DABT2+ molecule (H+: carrier concentration) were present in the (H2DABT2+)­(H2PO4–)2 and (H2DABT2+)­(H2PO4–)2(H3PO4)2 salts, respectively, which accounted for the highly proton-conducting behavior in the latter mixed protonated crystal. To design anhydrous intrinsic H+ conductors, both the mixed proton transfer state and uniform O–H···O hydrogen-bonding interaction are essential factors that must be considered

Molecular Assemblies of Tetrahedral Triphenylmethanol and Triphenylamine Derivatives Bearing −NHCOC_<i>n</i>H_2<i>n</i>+1 Chains

Nonplanar three-fold symmetrical triphenylmethanol (1: n = 10 and 2: n = 3) and triphenylamine (3: n = 10 and 4: n = 3) derivatives bearing three alkylamide (−NHCO­CnH2n+1) chains were studied in terms of their phase transitions, molecular assemblies, nano- or meso-structures, and dielectric responses. Slight modification of the structural core from a hydroxyl moiety (C–OH in 1) to a nitrogen atom (N in 3) drastically changed the molecular assembly structures and physical properties in solids. The molecular assembly of 1 showed a glass–plastic crystal phase transition at ∼340 K, whereas 3 only displayed a direct solid–liquid phase transition. Uniform microscale spheres and nanowires with average diameters of 2 μm and 200 nm, respectively, were observed for the molecular assemblies of 1 and 3 on substrate surfaces, respectively, corresponding to amorphous glass and one-dimensional hydrogen-bonding columnar structures. An α-type frequency- and temperature-dependent dielectric relaxation was observed in amorphous 1 during the glass–plastic crystal phase transition, whereas no dielectric anomalies were observed for 3. This difference was attributed to the subtle chemical modification of the central core from C–OH to N

Highly Proton-Conducting Mixed Proton-Transferred [(H₂PO₄^–)(H₃PO₄)]∞ Networks Supported by 2,2′-Diaminobithiazolium in Crystals

Hydrogen-bonding organic acid–base salts are promising candidates for the chemical design of high-performance anhydrous proton conductors. The simple molecular crystals between the π-planar molecules of 2,2′-diaminobithiazolium (DABT) derivative and hydrogen-bonding H3PO4 formed the proton-transferred salts with proton conductivities above ∼10–4 S cm–1 and anisotropic behavior. Controlling the crystallization condition facilitated the formation of binary salts between di-cationic H2DABT2+ and (H3PO4–)2 or mixed proton-transferred (H2PO4–)2(H3PO4)2 with different hydrogen-bonding networks, including one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) networks. The structural isomers of 2,2′-diamino-4,4′-bithiazolium (2,4-DABT) and 2,2′-diamino-5,5′-bithiazolium (2,5-DABT) formed a different type of packing structure even with the same crystal stoichiometry of (H2DABT2+)­(H2PO4–)2 and/or (H2DABT2+)­(H2PO4–)2(H3PO4)2 where the latter salt had different protonated species of H2PO4– and H3PO4 in the hydrogen-bonding network. Four and 10 protons per H2DABT2+ molecule (H+: carrier concentration) were present in the (H2DABT2+)­(H2PO4–)2 and (H2DABT2+)­(H2PO4–)2(H3PO4)2 salts, respectively, which accounted for the highly proton-conducting behavior in the latter mixed protonated crystal. To design anhydrous intrinsic H+ conductors, both the mixed proton transfer state and uniform O–H···O hydrogen-bonding interaction are essential factors that must be considered