Three dimensional CDW-ordering temperature in a quasi one dimensional electron-lattice system

Applying a phase transformation and taking an average over atomic scale variations, we get a reduced Hamiltonian of the Peierls-Fröhlich system, which is a coupled system of electrons and phase fluctuations of CDW essentially. Interchain coupling is assumed to be solely due to lattice vibrations. Three dimensional CDW-ordering temperature is obtained.     

Nonlinear diamagnetism due to the fluctuation superconductivity

Nonlinear susceptibility due to the fluctuation superconductivity is calculated microscopically in the Ginzburg-Landau-Garkov approximation. The characteristic field of the nonlinearity is given by H_c2.     

Strong,Self‐Healable,and Recyclable Visible‐Light‐Responsive Hydrogel Actuators

The most pressing challenges for light‐driven hydrogel actuators include reliance on UV light, slow response, poor mechanical properties, and limited functionalities. Now, a supramolecular design strategy is used to address these issues. Key is the use of a benzylimine‐functionalized anthracene group, which red‐shifts the absorption into the visible region and also stabilizes the supramolecular network through π–π interactions. Acid–ether hydrogen bonds are incorporated for energy dissipation under mechanical deformation and maintaining hydrophilicity of the network. This double‐crosslinked supramolecular hydrogel developed via a simple synthesis exhibits a unique combination of high strength, rapid self‐healing, and fast visible‐light‐driven shape morphing both in the wet and dry state. As all of the interactions are dynamic, the design enables the structures to be recycled and reprogrammed into different 3D objects.     

Magnitude and nature of carbohydrate-aromatic interactions in fucose-phenol and fucose-indole complexes: CCSD(T) level interaction energy calculations

The CH/π contact structures of the fucose-phenol and fucose-indole complexes and the stabilization energies by formation of the complexes (E(form)) were studied by ab initio molecular orbital calculations. The three types of interactions (CH/π and OH/π interactions and OH/O hydrogen bonds) were compared and evaluated in a single molecular system and at the same level of theory. The E(form) calculated for the most stable CH/π contact structure of the fucose-phenol complex at the CCSD(T) level (-4.9 kcal/mol) is close to that for the most stable CH/π contact structure of the fucose-benzene complex (-4.5 kcal/mol). On the other hand the most stable CH/π contact structure of the fucose-indole complex has substantially larger E(form) (-6.5 kcal/mol). The dispersion interaction is the major source of the attraction in the CH/π contact structures of the fucose-phenol and fucose-indole complexes as in the case of the fucose-benzene complex. The electrostatic interactions in the CH/π contact structures are small (less than 1.5 kcal/mol). The nature of the interactions between the nonpolar surface of the carbohydrate and aromatic rings is completely different from that of the conventional hydrogen bonds where the electrostatic interaction is the major source of the attraction. The distributed multipole analysis and DFT-SATP analysis show that the dispersion interactions in the CH/π contact structure of fucose-indole complex are substantially larger than those in the CH/π contact structures of fucose-benzene and fucose-phenol complexes. The large dispersion interactions are responsible for the large E(form) for the fucose-indole complex.     

Encapsulation‐Induced Remarkable Stability of a Hydrogen‐Bonded Heterocapsule

Remarkably enhanced stability of the self‐assembled hydrogen‐bonded heterocapsule 1?2 by the encapsulation of 1,4‐bis(1‐propynyl)benzene 3 a was found with K_a=1.14×10⁹ M ^?1 in CDCl₃ and K_a2=1.59×10⁸ M ^?2 in CD₃OD/CDCl₃ (10 % v/v) at 298 K. The formation of 3 a @( 1?2 ) was enthalpically driven (ΔH°<0 and ΔS°<0) and there was a unique inflection point in the correlation between ΔH° versus ΔS° as a function of polar solvent content. The ab initio calculations revealed that favorable guest–capsule dispersion and electrostatic interactions between the acetylenic parts (triple bonds) of 3 a and the aromatic inner space of 1?2 , as well as less structural deformation of 1?2 upon encapsulation of 3 a , play important roles in the remarkable stability of 3 a @( 1?2 ).     

Temperature-dependent 11B spin-lattice relaxation time for BF4 and CF3BF3 anions in room-temperature ionic liquids

Temperature-dependent (11)B T(1) values were measured for the BF(4) anion and BF(3) in the CF(3)BF(3) anion in room-temperature ionic liquids (RTILs) composed of the cation N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEME). Including the lithium-salt-doped samples, two neat and two binary ionic liquids were studied. Arrhenius plots of the (11)B T(1) showed T(1) minima for BF(4) in the temperature range between 243 (or above freezing) and 373 K. Using the Bloembergen, Pound, and Purcell(BPP) equations for the (11)B quadrupolar and (11)B-(19) F dipolar relaxation mechanisms, the correlation times for motions of BF(4) were calculated. Since the internal rotation of BF(3) is assumed in CF(3)BF(3), T(1) minimum was not observed. The effects of the addition of the lithium salt on the (11)B correlation time and (11)BT(1) for the anions in the ILs are discussed.     

Oxidative-stability enhancement and charge transport mechanism in glyme-lithium salt equimolar complexes

The oxidative stability of glyme molecules is enhanced by the complex formation with alkali metal cations. Clear liquid can be obtained by simply mixing glyme (triglyme or tetraglyme) with lithium bis(trifluoromethylsulfonyl)amide (Li[TFSA]) in a molar ratio of 1:1. The equimolar complex [Li(triglyme or tetraglyme)(1)][TFSA] maintains a stable liquid state over a wide temperature range and can be regarded as a room-temperature ionic liquid consisting of a [Li(glyme)(1)](+) complex cation and a [TFSA](-) anion, exhibiting high self-dissociativity (ionicity) at room temperature. The electrochemical oxidation of [Li(glyme)(1)][TFSA] takes place at the electrode potential of ~5 V vs Li/Li(+), while the oxidation of solutions containing excess glyme molecules ([Li(glyme)(x)][TFSA], x > 1) occurs at around 4 V vs Li/Li(+). This enhancement of oxidative stability is due to the donation of lone pairs of ether oxygen atoms to the Li(+) cation, resulting in the highest occupied molecular orbital (HOMO) energy level lowering of a glyme molecule, which is confirmed by ab initio molecular orbital calculations. The solvation state of a Li(+) cation and ion conduction mechanism in the [Li(glyme)(x)][TFSA] solutions is elucidated by means of nuclear magnetic resonance (NMR) and electrochemical methods. The experimental results strongly suggest that Li(+) cation conduction in the equimolar complex takes place by the migration of [Li(glyme)(1)](+) cations, whereas the ligand exchange mechanism is overlapped when interfacial electrochemical reactions of [Li(glyme)(1)](+) cations occur. The ligand exchange conduction mode is typically seen in a lithium battery with a configuration of [Li anode|[Li(glyme)(1)][TFSA]|LiCoO(2) cathode] when the discharge reaction of a LiCoO(2) cathode, that is, desolvation of [Li(glyme)(1)](+) and insertion of the resultant Li(+) into the cathode, occurs at the electrode-electrolyte interface. The battery can be operated for more than 200 charge-discharge cycles in the cell voltage range of 3.0-4.2 V, regardless of the use of ether-based electrolyte, because the ligand exchange rate is much faster than the electrode reaction rate.