Koichiro Shinra

Electronic transmission in trans-bis(1,2-dioximato)cobalt(III) complexes with organic bases—deprotonation reaction

Abstract The p K a values for the deprotonation reaction of intramolecular hydrogen bridges of trans -[Co(dmgH) 2 B 2 ] + , where dmgH is the dimethylglyoximate monoanion and B aniline, pyridine or their derivatives, have been determined spectrophotometrically. With increasing the electron-donor power of B the p K a values are increased. The axial pyridine derivatives decrease the p K a values of the complexes much more than the axial aniline derivatives. This characteristic behavior of the axial pyridine ligand has been observed in a series of the Co(III) complexes with methylethylglyoxime, cyclohexanedionedioxime and α-benzildioxime. In the complexes with B = pyridine derivatives, the additional formation of Co- B π-interaction has been postulated: the π-interaction may display a role withdrawing electron toward B and increasing the residual positive charge on the cobalt ion with a concomitant decrease of the electron density on the oxime groups.

Determination of the microstructure of polybutadiene by pyrolysis-gas chromatography

Abstract Pyrolysis-gas Chromatographic studies are presented for 1,4- cis -, 1,4- trans -and 1,2-polybutadiene. 1,4-Polybutadiene and 1,2-polybutadiene can be differentiated by the butadiene peak in the 1,4-polybutadiene pyrogram and a characteristic peak of 1,2-polybutadiene pyrogram. We found that there exists a hydrocarbon peak believed to be 1,8-dimethylperhydrophenanthrene, which is given only by 1,4- cis -polybutadiene.

The chemical shift of the hydroxyl proton of benzildioximes and furildioximes

Abstract The chemical shifts of the hydroxyl protons of benzil- and furildioxime isomers were measured in dimethyl sulfoxide or hexamethyl phosphorous triamide solvent. Each isomer gives a sharp signal at different fields and the signals are not affected by mixing of isomers, hence it is possible to determine and identify mixtures of the three isomers. The concentration and temperature dependences were investigated briefly.

Oxidation of nickel(II) and copper(II) complexes of NN-diethyldithiocarbamate

On reaction of copper(II) and nickel(II) complexes of NN-diethyldithiocarbamate with Br2 in CS2 solution, the central metal ions of the complexes are oxidised to form compounds of formula CuIII(dtc)Br2 and NiIV(dtc)2Br2, respectively.

Oxygenation and oxidation of manganese(II) complexes of NN-ethylenebis(salicylideneimine) and analogues

From the reaction of MnII(salen) or MnII(3-methoxy-salen),H2O with oxygen in organic solvents, three types of complexes have been isolated, which contain MnIII–O2–MnIII, [MnIV–O]n, or MnIVO bonds.

Syntheses of Polyquinazolones: Cyclopolycondensation Reactions of Imidoesters with Aromatic Aminoacids

イミドエステルと芳香族アミノ酸との反応について検討した。従来,イミドエステルと芳香族アミノ酸との反応では,4-ヒドロキシキナゾリン誘導体が得られるとされているが,本研究の反応で得られた生成物について赤外吸収スペクトル,NMRスペクトルおよび紫外吸収スペクトルより検討した結果,キナゾロン環の寄与が大きい化合物が得られていることを認めた。さらにイミドエステルおよび芳香族アミノ酸を2官能性に拡張して,ポリリン酸を溶媒とする溶液重縮合でポリキナゾロンを得た。ポリマーは耐熱性もかなり良好であった。