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71.
Yagi S Ezoe M Yonekura I Takagishi T Nakazumi H 《Journal of the American Chemical Society》2003,125(14):4068-4069
A novel porphyrinic receptor 1 in which two zinc porphyrins are bridged by two diarylurea linkers was developed for recognition of a viologen derivative (hexyl viologen, HV). The electronic absorption spectra as well as the 1H NMR experiments revealed that the HV molecule was bound to the cleft in 1 mainly through carbonyl dipole-charge interactions to afford a 1:1 complex. From the steady-state fluorescence spectroscopic study, the photoinduced electron transfer (PET) from 1 to HV was extremely facilitated by the receptor-substrate complexation. The receptor 1 also formed a 1:1 complex with 1,4-diazabicyclo[2.2.2]octane (DABCO) through two Zn-N coordination interactions, and, using DABCO as an inhibitor, we suppressed the PET reaction via the substrate exchange. 相似文献
72.
Yamaguchi T Sunatsuki Y Kojima M Akashi H Tsuchimoto M Re N Osa S Matsumoto N 《Chemical communications (Cambridge, England)》2004,(9):1048-1049
Dinuclear [(NiL)Gd(hfac)(2)(EtOH)](H(3)L = 1,1,1-tris(N-salicylideneaminomethyl)ethane, Hhfac = hexafluoroacetylacetone), trinuclear [(NiL)(2)Gd(NO(3))], and tetranuclear [(NiL)Gd(CH(3)CO(2))(2)(MeOH)](2) complexes, were prepared by treating [Ni(HL)] with [Gd(hfac)(3)(H(2)O)(2)], Gd(NO(3))(3).6H(2)O, and Gd(CH(3)CO(2))(3).4H(2)O, respectively, in the presence of Et(3)N. All the complexes show that ferromagnetic interactions occur between the Ni(II) and Gd(III) ions. 相似文献
73.
T Takahashi N Kakuhara S Katsuragawa Y Kojima A Hirose T Nakasato K Yoshioka K Kato T Yanagisawa 《Radioisotopes》1987,36(10):519-522
Patients with diffuse increased accumulation in both kidneys on 99mTc-MDP bone scintigram were evaluated quantitatively. Among 1,100 cases, 7 (0.63%) showed this finding. The accumulation density ratios of kidneys/lumbal vertebra in A/D exchanged images of these patients were compared with control group, so that these ratios of patient group were higher than control group statistically. In conclusion, the accumulation density ratio was made the index of diffuse increase accumulation in both kidneys on 99mTc-MDP bone scintigram. 相似文献
74.
Toru Takagishi Hiroshi Kozuka Nobuhiko Kuroki 《Journal of polymer science. Part A, Polymer chemistry》1983,21(2):447-455
A study was made of the formation of polyion complexes between a piperidinium cationic polymer and polyanions and of the binding of azo-dye anions (methyl, ethyl, propyl, and butyl orange) by these complexes. Sodium poly(acrylate), poly(styrenesulfonate), dextran sulfate, and carboxy-methylcellulose were used as polyanions. The resultant polyion complexes (insoluble in aqueous solutions) were compared for their ability to bind the small organic molecules in aqueous solutions, for example, of urea and an inorganic electrolyte (KCI), and exhibited a strong binding affinity toward these small anions. Polyion complexes that consisted of sodium poly(acrylate), dextran sulfate, and carboxymethylcellulose as polyanions cooperated in the binding, whereas the polyion complex of sodium poly(styrenesulfonate) did not. It was suggested that small organic anions interact with the polyion complexes primarily through electrostatic and hydrophobic forces. 相似文献
75.
Toru Takagishi Katsushige Takami Nobuhiko Kuroki 《Journal of polymer science. Part A, Polymer chemistry》1974,12(1):191-200
The binding of 4′-dibutylaminoazobenzene-4-sulfonate anion (butyl orange) by bovine serum albumin has been examined quantitatively by an equilibrium dialysis method at 5, 10, 15, 20, 25, and 35°C. The first binding constants and the thermodynamic parameters for the formation of the first dye anion-protein complex have been calculated. The peculiar temperature dependence of the first binding constant could be observed. That is, the value of the first binding constant increases with increasing temperature until it reaches a maximum value at approximately 18°C and then decreases with raising temperature. Accordingly, this binding process is exothermic above 18°C and is endothermic below 18°C. Near 18°C the process exhibits athermal reaction. From the thermodynamic data obtained, it is evident that the favorable free energy of the binding is accompanied by an entropy gain and that the enthalpies of the binding vary from a positive (unfavorable) value below 18°C to a negative (favorable) one above 18°C. Furthermore an apparent temperature dependence of the thermodynamic functions was observed. That is, ΔF° becomes larger in absolute magnitude as the temperature increases. The positive quantity of ΔS° tends to decrease with increasing temperature. All these facts can be interpreted satisfactorily in terms of hydrophobic interactions between hydrophobic portions of the dye and nonpolar parts of the albumin. 相似文献
76.
Masaru Kojima 《Tetrahedron letters》2007,48(25):4431-4436
A new fluorous benzylidene acetal protecting group was regioselectively introduced into carbohydrates, deprotected under acidic conditions, and reused. Oligosaccharides were synthesized via regioselective conversion of the fluorous acetal group to the benzyl group by traditional reaction conditions. The fluorous compounds were easily separated from non-fluorous by-products by fluorous solid phase extraction. 相似文献
77.
T. Nakamura S. Kojima T. Ohta M. Nishida A. Rakowski A. Ikeda H. Oda E. Niu 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(2):327-332
14C variations of atmospheric CO2 as well as carbonaceous fraction of living materials, such as collagen from tooth and bone, tissue, skin, hair, nail, etc.,
of modern humans are influenced by 14C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of
14C concentration of tree rings and human body samples formed in this time intervals, we can establish a relationship of their
14C concentrations with calendar year. By applying this relation to a sample whose 14C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the chemicals that
were used in some criminal cases can be possibly identified, by their carbon isotope ratios (13C/12C and 14C/12C). This method of age determination has been applied to a forensic study, i.e., two criminal cases of murder. For each case,
by comparing the measured 14C abundances of several pieces of hair and one tooth (the third molar) from the body with the annual change on concentrations
of bomb-produced 14C, the time of death of the body and the age of the victim were estimated. The estimated values were consistent with the real
ones that were revealed by the confession of the real murderers. 相似文献
78.
Yoshihiko Ito Yoshinori Inubushi Toru Sugaya Takeo Saegusa 《Journal of organometallic chemistry》1977,137(1):1-9
Reaction of carboxamides with Cu2O in the presence of t-butyl isocyanide gave new chelated copper(I) complexes, which probably are formed by the insertion of t-butyl isocyanide into the coppernitrogen bond of copper(I) amide isonitrile complexes, which were initially produced from the carboxamides and Cu2Ot-butyl isocyanide complex. The same chelated copper(I) complexes were prepared more readily by the reaction of the corresponding N-trimethylsilyl-carboxamides with Cu2Ot-butyl isocyanide complex. Reactions of the copper(I) complexes thus obtained with alkylating agents, such as alkyl halides, alkyl tosylates and triethyloxonium tetrafluoroborate, also were described. 相似文献
79.
Murahashi S Imada Y Kawakami T Harada K Yonemushi Y Tomita N 《Journal of the American Chemical Society》2002,124(12):2888-2889
A chiral titanium complex, Ti(O-i-Pr)(4)/BINOL/tert-butylcatechol, catalyzes enantioselective addition reaction of ketene silyl acetals to nitrones to give optically active beta-amino acid derivatives which are biologically active compounds and useful synthetic intermediates of natural products and pharmaceuticals such as beta-lactam antibiotics. The combined process of catalytic oxidation of secondary amines and enantioselective carbon-carbon bond formation of nitrones thus obtained with ketene silyl acetals provides a useful two-step method for the synthesis of optically active beta-amino acid derivatives and related nitrogen compounds. 相似文献
80.
Masahito Segi Katsuhiko Tanno Masumi Kojima Mitsunori Honda Tadashi Nakajima 《Tetrahedron letters》2007,48(13):2303-2306
1,3-Dipolar cycloaddition between aromatic selenoaldehydes, generated by thermal retro Diels-Alder reaction of anthracene cycloadducts, and nitrile oxides or nitrile imines proceeded efficiently to give the corresponding [3+2] cycloadducts as a single isomer in good yields, being 1,4,2-oxaselenazoles or 1,3,4-selenadiazoles, respectively. 相似文献