Aromaticity and π-bond covalency: prominent intermolecular covalent bonding interaction of a Kekulé hydrocarbon with very significant singlet biradical character

An anthracene-linked bisphenalenyl Kekulé molecule with very significant singlet biradical character has shown a prominent covalent bonding interaction between molecules in a molecular aggregate. High aromatic stabilization energy in the anthracene linker is responsible for the significant singlet biradical character.     

The polarized reflectance spectrum of a novel organic conductor (BEDT-TTF)2ClO4(C2H3Cl3)0.5

The polarized reflectance spectrum of a novel organic conductor, (BEDT-TTF)₂ClO₄(C₂H₃Cl₃)_0.5 was measured at room temperature over the spectral region from 340 cm^-1 to 25000 cm^-1. The reflectance spectrum provided an evidence for the anisotropic two-dimensional character of this material. The optical conductivity spectrum exhibits the existence of an optical band gap of about 0.2 eV, suggesting that this material is a semimetal rather than a metal.     

Low-temperature reflection spectrum of K-TCNQ single crystal

Polarized reflection spectra of a K-TCNQ single crystal have been measured at 27,295 and 413 K. The absorption spectra were derived from the observed reflection spectra by Kramers-Kronig transformation. At 27 K, the near-infrared absorption band which is associated with the charged transfer between TCNQ^? ions, splits into a strong sharp peak at 8 × 10³ cm^?1 and a weak broad band at 11 × 10³ cm^?1. These bands were interpreted in terms of the strongly correlated extended Hubbard model including the nearest-neighbor Coulomb interaction.     

Study of the Phase Transitions of (DI-DCNQI)2M (M=Ag, Li,Cu) through the Analysis of the Temperature-Dependent Vibronic and Vibrational Infrared Absorptions

The temperature-dependent phase transitions of 2,5 diiodo-dicyanoquinondiimmine (2,5-DI-DCNQI) title compounds are analyzed by looking at the bond order wave (BOW) and at the charge density wave (CDW) which characterizes the transitions. The analysis is done by studying the temperature-dependent powder infrared spectra which allow one to have a separate evaluation of both types of contribution to the phase transition of these molecular metals. A model for the spectroscopic infrared features related to the transitions is reported and used for the analysis. It is found that all the title compounds develop a BOW structure at low temperatures with characteristics which recall an instability toward a tetramerized 2k_F periodicity particularly for the Ag and Li compounds. An appreciable CDW amplitude contribution to the transitions is not found in the spectra.     

Theoretical study of the transesterification reaction of polyethylene terephthalate under basic conditions

The depolymerization reaction of polyethylene terephthalate (PET) was analyzed using a computational chemistry approach. The reaction is a type of transesterification reaction using alkoxide. In this study we employed the calculated optimum structure, electrostatic potential distribution, activation energy, electric charges and pathway to investigate the mechanism. We found that the tetrahedral intermediate produced by ring formation with alkoxide is an essential feature of the depolymerization process. Moreover, there is a possibility that a PET molecule is depolymerized by multiple alkoxides at the same time. However, the effects of degree of polymerization and the position of attack by the alkoxides do not strongly influence the reactivity.     

In Vitro Thermal and Ethanol Adaptations to Improve Vinegar Fermentation at High Temperature of Komagataeibacter oboediens MSKU 3

Applied Biochemistry and Biotechnology - High temperature and high ethanol concentrations obviously affect vinegar fermentation. The thermotolerant and ethanol-resistant strains are expected to...     

Temperature dependence of the reflectance spectrum of the single crystal of tetrathiafulvalene-chloranil

Near-infrared and visible reflectance spectrum was measured on the tetrathiafulvalene-chloranil (TTF-CA) crystal at temperatures in the range of 40–290 K. An abrupt change of reflectivity was found at about 80 K, and new dispersions associated with the intramolecular transitions of TTF⁺ and CA^? gradually grew up on lowering temperature below 80 K, indicating the increase of the ionized fraction.     

Temperature dependence of the reflectance spectrum of tetrathiafulvalenium iodide (TTF)I0.71 single crystal

The reflectance spectrum of (TTF)I_0.71 exhibits a Drude-like plasma edge near 10 × 10³ cm^-1, and the reflectivity below this region increases as the temperature is lowered from room temperature to 210 K. However, the near-infrared reflectivity decreases with lowering temperature in the semiconductive phase below 210 K, and an additional peak attributable to the charge transfer between (TTF)⁺ ions grows up as the temperature is lowered. Discussion is given on these behaviors of (TTF)I_0.71.