Electron spin resonance spectra and hyperfine coupling constants of the α-tocopheroxyl and 2,2,5,7,8-pentamethyl-chroman-6-oxyl radicals derived from vitamin E and its model and deuterated model compounds

Highly resolved electron spin resonance spectra of the α-tocopheroxyl or 2,2,5,7,8-pentamethylchroman-6-oxyl radicals were obtained from the oxidation of α-tocopherol (vitamin E) or its model compound, 2,2,5,7,8-pentamethylchroman-6-ol, with 2,2-diphenyl-1-picrylhydrazyl or superoxide ion. Complete assignments of the hyperfine coupling constants of these radicals were made on the basis of the spectra of the deuterated isotopomers of the 2,2,5,7,8-pentamethylchroman-6-oxyl radical. The large coupling constant due to the methyl group at C-5 in the α-tocopheroxyl radical may have implications for the high reactivity toward radicals of C-5 in α-tocopherol.     

Preparation and O2 binding study of myoglobin having a cobalt porphycene

Sperm whale myoglobin, an oxygen-storage hemoprotein, was reconstituted with 2,7-diethyl-3,6,12,17-tetramethyl-13,16-bis(carboxyethyl)porphycenatocobalt(II) in order to investigate the reactivities of a cobalt porphycene in a protein matrix. Similar to the previously reported finding for the myoglobin with the iron porphycene, the reconstituted myoglobin with the cobalt porphycene was also found to have an O2 affinity 2 orders of magnitude greater than that of the myoglobin possessing cobalt protoporphyrin IX. The EPR spectra of the deoxy and oxy myoglobins having the cobalt porphycene at 77 K also have features similar to those of the myoglobin with cobalt protoporphyrin IX. These spectra suggest that the porphycene cobalt in the deoxy form is coordinated by one nitrogenous ligand postulated to be the imidazole ring of His93, and that the bond configuration of CoII-O2 is regarded as the CoIII-Omicron2*- species.     

A study on vertical distribution of elements and their chemical states in Yatsu tideland sediments

We have clarified vertical distribution of thirty and more elements in the Yatsu tideland sediment by instrumental neutron activation analysis (INAA) and prompt g-ray analysis (PGA). The distributions of elements were categorized into three groups according the tendency of each vertical distribution. Chemical states of iron in the sediments were investigated by Mössbauer spectroscopy. In the distribution of iron species, maximum pyrite distribution was found in the middle layer. Paramagnetic high-spin Fe²⁺ distributed complementarily to pyrite, suggesting that the Fe²⁺ was used for pyrite formation.     

Palladium(II), platinum(II), rhodium(III) and iridium(III) complexes coordinated with 2-aryl-4,5-dimethyl-1,2,3-triazoles as bidentate nitrogen-carbon chelate ligands

Summary Cyclometallations of 2-aryl-4,5-dimethyl-1,2,3-triazoles [H(C-N)] occur with palladium(II), platinum(II), rhodium(III) and iridium(III) chloride. Pallaciation and platination form [MCI(C-N)]₂, and rhodation and iridation [MCI(C-N)₂]₂ species. These complexes react with monodentate ligands, L, such as pyridine and tri-n-butylphosphine to give MCl(C-N)L and MCl(C-N)₂ L complexes. Corresponding bromo and iodo complexes are prepared by metathesis with lithium bromide and iodide. Spectroscopic data suggest that MX(C-N)L compounds (X = Cl, Br or I) have a structure withtrans-C,X andtrans-N,L, while [MX(C-N)₂ L] has atrans-N,N,cis-C,C, andcis-X,L structure.Author to whom all correspondence should be directed.     

An application of Aomoto-Gelfand hypergeometric functions to theSU(n) Knizhnik-Zamolodchikov equation

Solutions to the Knizhnik-Zamolodchikov equation for Verma modules of the Lie algebra are explicitly given by certain integrals called Aomoto-Gelfand hypergeometric functions.