The growth of lamellar crystals has been studied in particular for spherulites in polymeric materials. Even though such spherulitic structures and their growth are of crucial importance for the mechanical and optical properties of the resulting polymeric materials, several issues regarding the residual stress remain unresolved in the wider context of crystal growth. To gain further insight into micro-mechanical forces during the crystallization process of lamellar crystals in polymeric materials, herein, we introduce tetraarylsuccinonitrile (TASN), which generates relatively stable radicals with yellow fluorescence upon homolytic cleavage at the central C–C bond in response to mechanical stress, into crystalline polymers. The obtained crystalline polymers with TASN at the center of the polymer chain allow not only to visualize the stress arising from micro-mechanical forces during polymer crystallization via fluorescence microscopy but also to evaluate the micro-mechanical forces upon growing polymer lamellar crystals by electron paramagnetic resonance, which is able to detect the radicals generated during polymer crystallization.
We studied the separative recovery of oxygen formed during the hydrogenation of carbon dioxide using a composite system consisting of yttria-stabilized zirconia (YSZ) membrane-equipped Ag electrodes as a pump and a nickel/zeolite catalyst to initiate the hydrogenation of carbon dioxide. The methanation of carbon dioxide proceeded efficiently in the presence of the nickel/zeolite catalyst even at 873 K, the lowest functional temperature at which YSZ has ionic conductivity. Carbon dioxide conversion and methane yield reached 100% and 80%, respectively, at H 2 /CO 2 ) 10, space velocity < 6200 h -1 , and 873 K. Carbon dioxide was adsorbed by the crystal structure of the zeolite even at 873 K, and methanation of the adsorbed carbon dioxide (CO 2 ad ) proceeded by the following one-step reaction: CO 2 ad + 3H 2 f CH 4 + H 2 O. The rate constant of methanation was estimated to be 1.6 × 10 -2 cm 3 g-cat -1 s -1 for the pseudo-first-order reaction. Electrochemical isolation of oxygen formed during hydrogenation of carbon dioxide was carried out under galvanostatic conditions. It was assumed that the oxygen was converted to water by the nickel/ zeolite catalyst and then transported through the YSZ electrolyte after the water was ionized. We assumed that the oxygen was not formed by the dissociation of carbon dioxide directly on the cathode electrode. It appeared that the charge-transfer process was the rate-determining step for isolation of oxygen on the cathode electrode in the presence of the nickel/zeolite catalyst.
For dye-sensitized solar cells, phthalocyanines require strong absorption of far-red light between 700 and 850 nm because of their high electron transfer efficiency. Nevertheless phthalocyanines lack of affinity to basal plats, they inhibit utilization as dye-sensitized solar cell photosensitizer. Then, subphthalocyanines are used as precursors to prepare asymmetric 3:1 type phthalocyanines using a ring-enlargement technique to give affinity to basal plates. As subphthalocyanines having arylsulfanyl substituents used as a precursor, asymmetric phthalocyanines are expected to have good affinity to basal plates. Spectroscopic properties and electron transfer abilities to synthesize non-peripheral arylsulfanyl-subphthalocyanines were estimated. In addition to prepare as trial, asymmetric 3:1 type phthalocyanine, hexakis[(4-methylphenyl)thio]phthalocyanine, was synthesized from corresponding subphthalocyanine.
Phthalocyanines-related compounds, subphthalocyanines, are the homologues consisting of three isoindole units with boron as the center. The absorption maximum of subphthalocyanines, called the Q band, appears around 560 -630 nm, which is shifted by approximately 100 nm to shorter wavelengths compared to phthalocyanines. Subphthalocyanines are used as precursors to prepare unsymmetric phthalocyanines for ring enlargement reaction. In this decade, phthalocyanines are used for dye-sensitized solar cells (DSSCs), which require strong absorption of far-red light between 700 and 850 nm because of their highly efficiency. Non-peripheral thioaryl-substituted phthalocyanines have been synthesized. They show near-infrared absorption around 780 -870 nm and have excellent electron transfer properties. However, their lack of affinity to basal plats inhibits their use as DSSC photosensitizer. Therefore, to synthesize unsymmetrical non-peripheral thioaryl-substituted phthalocyanines possessing good affinity to basal plates, the authors prepared subphthalocyanines having thioaryl substituents as precursors. Spectroscopic properties and electron transfer abilities to synthesize non-peripheral thioaryl-substituted subphthalocyanines were estimated using cyclic voltammetry. The Q band of non-peripheral thioaryl-substituted subphthalocyanines shows around 650 nm shifted to longer wavelength by 86 nm in comparison to subphthalocyanine. The compounds show many reduction potentials. They are acceptable electrons in the subphthalocyanine ring, meaning that the compounds have good electron transfer * Corresponding author.K. Sakamoto et al. 1038 properties.
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