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.     

Cerebral energy metabolism in rats studied by phosphorus nuclear magnetic resonance using surface coils

Phosphorus nuclear magnetic resonance with surface coils was used to investigate the regional metabolism of the rat brain in vivo under conditions of normoxia, severe hypoxemia, partial necrosis, and partial ischemia. The results show an increase in sugar phosphate and/or inorganic phosphate with injury in accordance with in vivo assays. The technique provides a powerful means of monitoring the metabolism of stroke and its response to therapy in vivo.     

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.     

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.     

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.     

Synthesis, structural characterization and magnetic property of nanocomposite materials: Intercalation compounds of FePS_3 with 1,10-phenanthroline or 2,2''''-bipyridine

Two new intercalation compounds Fe0.90PS3(phen)0.41 (1) (phen stands for 1,10-phenanthroline including a part of 1, 10-phenanthroline H ) and Fe0.83PS3(bipy)0.34 (2) (bipy stands for 2,2'-bipyridine H ) were synthesized by the reaction of the layered FePS, with 1,10-phenanthroline or 2,2'-bipyridine in the presence of anilinium chloride. They were characterized by elemental analyses, powder X-ray diffraction (XRD), infrared spectroscopy. The lattice spacing of the intercalate was expanded by 0.90 nm for Fe0.90PS3(phen)0.41 and 0.57 nm for Fe0.83PS3(bipy)0.34 withrespect to the pristine FePS3, indicating that the ring plane of the guests is perpendicular to the layer of the host. The UV-vis absorption spectra of the filtrate in preparation of the intercalates indicate that 1, 10-phenanthroline or 2,2'-bipyridine also acts as a complexing agent to remove intralamellar Fe2 ions into the solution during intercalation. The magnetic properties of 1 and 2 were studied.     

The Intercalation Reaction of 1,10-Phenanthroline with Layered Compound FePS3

The intercalation reaction of 1,10-phenanthroline with FePS₃ in ethanol and in the presence of anilinium chloride has been monitored in detail with the X-ray powder diffraction (XRD) method to study the reaction mechanism. It is revealed that during the intercalation period there are three phases: the 001 phase (corresponding to the perpendicular orientation of the 1,10-phenanthroline ring with the layer of the host FePS₃), the 001′ phase (standing for the parallel orientation of the 1,10-phenanthroline ring with the layer), and the 001″ phase (pristine FePS₃), but as the period of the reaction is prolonged, the 001′ and 001″ phases diminish gradually and finally disappear, and the 001 phase is intensified and a complete intercalate is obtained for Series A, in which excess 1,10-phenanthroline is used. However, for Series B in which the optimum amount of 1,10-phenanthroline is used, the 001 and 001″ phases diminish gradually, and another intercalate is obtained that exhibits the 001′ phase. Moreover, if the amount of phenanthroline used in the reaction is more than that in Series B but not in excess, another intercalate containing 001 and 001′ phases is obtained. In these intercalation reactions, the results of IR spectroscopy indicate that anilinium chloride serves only as the source of protons for 1,10-phenanthroline, but 1,10-phenanthroline acts as both the complexing agent of Fe²⁺ ions removed from FePS₃, confirmed by UV spectra of the filtrates, and the inserted guest, some of which exists in the form of protonated cation to maintain the charge balance of the intercalates. From the experimental evidence we find that the arranged orientation of 1,10-phenanthroline between the layers is controlled by the amount of guest used in the reaction, and a possible intercalation mechanism is proposed for the reaction.