Electronic structure of thiazine-indigo pigment on the basis of the crystal structure

Thiazine-indigos are novel hydrogen-bonded pigments developed recently by Clariant that exhibit a variety of shades from yellow to red. Among these, a commercially available chlorinated derivative (THI) gives a color of vivid red, although it is only pale yellow in solution. For this reason, electronic characterization of THI has been carried out on the basis of the crystal structure. There are chains of intermolecular hydrogen bonds between the N-H group of one molecule and the O atom of the neighboring one along the b-axis, forming a two-dimensional hydrogen bond network. The direction of the transition dipole points along the long molecular axis, and the transition dipoles are arranged in "head-to-tail" fashion along the (b,-c) diagonal direction. The large bathochromic shift upon crystallization can be mostly attributed to excitonic interactions between transition dipoles arranged diagonally along the stacking axis as well as those in head-to-tail fashion on the molecular plane.     

Preparation of benzolactams by Pd(OAc)2-catalyzed direct aromatic carbonylation

We developed a new method for Pd(II)-catalyzed direct aromatic carbonylation in a phosphine-free catalytic system using Pd(OAc)2 and Cu(OAc)2 in an atmosphere of CO gas containing air. The carbonylation proceeded with ortho-palladation, inducing a remarkable site selectivity to afford a variety of five- or six-membered benzolactams from secondary omega-arylalkylamines, such as N-alkylbenzylamines or N-alkylphenethylamines.     

The photochemical reactions of 5H-benzo[a]phenoxazin-5-one with alkylthiols and thiophenol

6-Alkylthio- and 6-phenylthio-5H-benzo[a]phenoxazin-5-ones have been synthesized by the photochemical reaction of 5H-benzo[a]phenoxazin-5-one with alkylthiols and thiophenol.     

Irradiation conditions required in combined radiation-microbial process for landfill leachate

A landfill leachate, which contains large amounts of microbially refractory humic substances, was irradiated with 60Co gamma-rays under several conditions and the modification of its biodegradability was examined. The effects of initial pH and dose rate on the modification were found to be insignificant. The apparent effect was observed for the initial concentration of the humic substances. High biochemical oxygen demand (BOD) value was obtained as the initial concentration was higher. As the initial concentration was lower, in contrast, the decreasing rates of total organic carbon (TOC) and chemical oxygen demand (COD) were high. Therefore two possible designs of the combined radiation-microbial processes with and without dilution are proposed. Both processes require only about 30% of the irradiation dose, compared with a simple radiation process.     

Polycondensation of bis(p-nitrophenyl) β-truxinate with diamine

Model reaction of bis(4-nitrophenyl) β-truxinate (BNPT) with aliphatic amines proceeded quantitatively at room temperature. Accordingly, polycondensation of BNPT with various diamines was carried out at room temperature or 80°C. During the polycondensation of BNPT with diamines, the precipitation of polymer or the observed gelation of polymerization solution occurred, which may limit the molecular weight of the polymer. On the other hand, the reaction of BNPT with 1,3-(4-piperidyl)propane (DPP) proceeded homogeneously to give the polymer with relatively high molecular weight, and the obtained polyamide (P-1e) showed excellent solubility in many solvents. The study of TG and DTA indicated that the obtained polymers were stable at lower temperature than around 270°C. The polymer prepared from the polycondensation of BNPT with hexamethylenediamine showed melting point and decomposition due to the imidation at 282°C. The photochemical reaction of these polymers was carried out in the film state. The irradiation of 254 nm light caused an absorption at 272 nm to appear and the molecular weight to decrease. This meant that the scission of cyclobutane ring in the main chain occurred to give cinnamamide structures. Also, the absorption at 272 nm decreased by the irradiation of 302.5 nm light. However, the UV spectrum of irradiated polymer did not agree with that of the original polymer. These results suggested that the dimerization of the resulting cinnamamide moieties occurred in the competition of their trans–cis-isomerization. On the other hand, the rate of scission of cyclobutane ring of P-1e was faster than that of the corresponding polyamide containing α-truxillamide structure.     

The photochemical reactions of 5H-benzo[a]phenothiazin-5-one with alkylthiols and thiophenol

6-Alkylthio- and 6-phenylthio-5H-benzo[a]phenothiazin-5-ones were prepared by the photochemical reaction of 5H-benzo[a]phenothiazin-5-one with alkylthiols and thiophenol. The structures of newly prepared compounds were determined by elemental analysis, spectroscopic methods (ir, nmr and ms) and comparison with a sample prepared by an alternate route.     

Measurement of Spectral Emissivity and Thermal Conductivity of Zirconia by Thermal Radiation Calorimetry

The hemispherical total emissivity of partially stabilized zirconia has been obtained by a spectral analysis of the normal emission spectra between 400–850 K. Thermal conductivity was evaluated with this emissivity and temperature gradient in the sample. Effects of the scattering of the radiation in a ceramic sample are also investigated. In addition, specific heat capacity was measured by thermal radiation calorimetry. Current results are compared with those reported for tetragonal zirconia with the same yttria content and for monoclinic phase. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphosynthesis of poly[4‐(1,4‐phenylene)oxyphthalimide] and copolymers prepared by reaction‐induced crystallization during polymerization

Morphosynthesis of poly[4‐(1,4‐phenylene)oxyphthalimide] (POPI) and poly[4‐(1,4‐phenylene)oxyphthalimide‐co‐4‐phthalimide] (POPI‐PPI) was examined by using the crystallization during the polymerization. The POPI fibrillar crystals were obtained as precipitates with the formation of spherical aggregates of plate‐like crystals. Some of the POPI fibrillar crystals were longer than 15 μm. They possessed high crystallinity and the molecules aligned perpendicular to the long direction of the fibers. On the other hand, one‐dimensional structures of POPI‐PPI such as ribbon, cone, rod, and fiber were obtained as precipitates by the copolymerization. The copolymer molecules might align along the long direction of the cone‐like crystals. The morphology of these poly(ether‐imide)s could be controlled by not only the polymerization condition but also with the aid of copolymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012