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Table of Content

    20 August 1989, Volume 7 Issue 3
    THE RELATION BETWEEN PHOTOGRAPHIC ACTIVITIES AND STRUCTURES OF PYRAZOLONE COLOUR COUPLERS
    CHEN ZHE-LIU, ZHU ZHENG-HUA, CHEN KONG-CHANG, HE YUE-HUA
    1989, 7(3):  1-6.  DOI: 10.7517/j.issn.1674-0475.1989.03.1
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    Seven pyrazolone colour couplers were prepared and their photographic activities A were determined. SCF-PPP-MO was used to calculate the electron densities, localization energies and superdelocalizabilities at the coupling sites of colour couplers. The calculated electron densities Qr, were found to correlate lnA by a linear equation: lnA=15.97Qr-18.03 (n=6,r=0.95) Since A should be directly proportional to k2, the specific rate constant of colour coupling, Qr is related to coulombic attraction between reacting molecules. The coupling reaction of pyrazolone is an electrostatic controlled reaction.
    AROMATIC DISULFIDES/VINYL MONOMERS PHOTOPOLYMERIZATION VIA COMPLEXATION
    LI MIAO-ZHEN, CHANG ZHI-YING, NIE JUN, WANG ER-JIAN
    1989, 7(3):  7-14.  DOI: 10.7517/j.issn.1674-0475.1989.03.7
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    In this paper p-substituted diphenyl disulfides (DS) were used as initiators for photo-polymerization. The polymerization rates (Rr) of vinyl monomers increase in the order AN > MM A > St. Acrylonitrile is the most efficient one. The influence of DS structure, concentration of monomer and DS, and the nature of solvents are also studied. The steady and transient electron spectra measured indicate that the intermolecular complex in the ground state and in excited state are formed between DS and M in this system. The excited com-plex exhibits relative long lifetime and facilitates the radical photogeneration of DS. The mechanism of the primary photochemical process of DS was discussed.
    A TRANSIENT STUDY ON THE KETOCOUMARIN DERIVATIVES Ⅲ. THE ELECTRON TRANSFER BETWEEN KETOCOUMARIN DERIVATIVES AND IODONIUM SALTS
    Wu SHI-KANG, ZHANG JIAN-KE, J. P. Fouassier, D. Burr
    1989, 7(3):  15-19.  DOI: 10.7517/j.issn.1674-0475.1989.03.15
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    In this work, the ketocoumarin derivatives have been studied as a sensitizer for iodonium salts by laser flash photolysis method. Results show that the excited triplet state of ketocon-marin derivatives can be quenched by iodonium salts through the mechanism of electron transfer. The methyl viologen (PQ2+) was used as a model compound instead of iodonium salt and the same phenomenon of triplet state quenching was also observed. Simultaneously, a new signal placed at 610 nm, which indicates the cationic radical (PQ+) formation of methyl viologen, was observed. These results show that the ketocoumarin derivatives are certainly applied as electron donors in the electron transfer reactions. The calculated result by weller equation demonstrates that the electron transfer process may be occured between ketocoumarin derivatives and iodonium salts.
    SERS OF CYANINE DYES ADSORBED ON THE SURFACE OF SILVER ELECTRODE
    WANG HUI-TAO, HUANG DE-YIN, Yu ZU-HAN, YAO WEN-HUA
    1989, 7(3):  20-26.  DOI: 10.7517/j.issn.1674-0475.1989.03.20
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    Two model systems, Ag/NaBr+Dye-798 and Ag/NaBr+Dye-1556 have been used in this work. The orientation of the dye molecules, adsorbed on the surface of silver electrode, the stabilization of adsorption, and the competition between two adsorbed dyes were studied by the method of SERS (Surface Enhanced Raman Spectra).By the comparison of Raman Spectra of solid dyes and SERS of adsorbed dyes, it was found that those two dyes have different adsorption behaviors on the surface of silver electrode, and the molecules of two dyes are almost perpendicular to the electrode surface.
    ESR STUDY ON THE ACTIVE FREE RADICALS FORMED DURING THE PHOTOLYSIS OF ORGANO-STANNUM COMPOUNDS
    WANG XIU-HUA, Liu YANG, Xu GUANG-ZHI, LIANG REN-YOU
    1989, 7(3):  27-33.  DOI: 10.7517/j.issn.1674-0475.1989.03.27
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    Active free radicals produced during the photolysis of organo-stannum compounds have been studied by the combination of spin trapping technique and ESR spectroscopy. The results show that during the UV irradiation the C-Sn bond of organo-stannum compounds is cleaved and both C-centre and Sn-centre radicals are produced, of which the C-centre radical can be trapped by PBN or ND and a stable cyclic adduct is formed from Sn-centre radical and phenanthrenequinone. It is also interesting to note that owing to the different coordinate of cyclic adduct and the difference of steric effect, the ESR signal is quite different and the spin density on the adduct is changed.
    THE CONFORMATION AND INTRAMOLECULAR EXCIMER FORMATION OF POLYETHYLENE GLYCOL BIS-2-NAPHTHOATES IN METHANOL
    WANG YI-MING, TUNG CHEN-HO, Xu HUI-JUN
    1989, 7(3):  34-39.  DOI: 10.7517/j.issn.1674-0475.1989.03.34
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    The fluorescence of polyethylene glycol bis-2-naphthoates (Pn) in different solvents were measured under stationary and nonstationary conditions at various temperatures. Contrary to that in good solvents such as tetrahydrofuran, Pn show strong excimer emission in methanol, suggesting that hydrophobic interactions bring the two chromophores of Pn in proximity. The activation energy and enthalpy change for excimer formation were obtained to be 8.5 kJ/mol and -20 kJ/mol respectively. The rates for excimer formation and dissociation were also calculated to be 4.5×108s-1 and 3.1×108s-1 respectively by means of time-resolved fluorescence measurement.
    THERMODYNAMIC PROPERTIES OF SELF-ASSOCIATION OF PHOTOGRAPHIC SPECTRAL SENSITIZING CYANINE DYES 1. DIMERIZATION OF 3,3’-DI-(r-SULFOPROPYL)-9-ETHYL-4,5,4’5’- DIBENZOTHIA-CARBOCYANINE DYE IN DMF-WATERMIXED SOLVENTS AND HEAT OF DIMERIZATIONMEAS
    GONG YONG-KUAN, SHEN JIE-RU, ZHONO GUANG-XUE, ZHANG ZU-XUN
    1989, 7(3):  40-45.  DOI: 10.7517/j.issn.1674-0475.1989.03.40
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    The absorption spectra of 3, 3’-di-(γ-sulfopropyl) -9-ethyl-4,5,4’,5’-dibenzothia-carbocyani ne triethylamine salt (I) in DMF-H2O mixed solvvents of various compositions showed dimer-mo-nomer equilibrium at room temperature within a certain concentration range. For these solutions, the dilution heat effects were measured with the home-made Versatile Precision Semiconductor Calorimetric System made in this laboratory. Dimerization enthalpy △H, △G and △S, which for 1 mole dimer formation at 25℃ in solvents of 45% and 35% DMF (by volume), were found to be: -(49.6±1.3), -(36.0±1.0)kJ;- (13.1±0.1),-(19.9±0.1) kJ and -(122.7±3.2),-(54.0±1.5)J·K-1 respectively.
    1989, 7(3):  46-55.  DOI: 10.7517/j.issn.1674-0475.1989.03.46
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    1989, 7(3):  56-64.  DOI: 10.7517/j.issn.1674-0475.1989.03.56
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    THE EFFECT OF SOME PHOTOGRAPHIC ADDITIVES ON THE GEL STRENGTH OF GELATIN
    XIONG LIANG-WEN, PENG BI-XIAN
    1989, 7(3):  65-67.  DOI: 10.7517/j.issn.1674-0475.1989.03.65
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    In present paper the effect of potassium thiocyanate, ammonium thiocyanate, thiourea and urea on gel strength of photographic gelatins was investigated. It is found that with the increase of amount of above-mentioned additives the monotonous and linear decrease of the gel strength of gelatin was observed. Gel strength is one of the key physicomechanical behaviour parameters of photographic gelatin. The discovery implies that in order to improve the physio-mechanical property of gelatin and (or) gelatin-silver halide emulsion layer it is of great importance to properly and reasonably apply above-mentioned additives in emulsion-making or explore the new type of additives without harmful influence on the gel strength of photographic gelatins.
    THE EFFECT OF SOME PHOTOGRAPHIC ADDITIVES ON THE RENATURATION ABILITY OF THE GELATIN MACROMOLECULE
    XIONG LIANG-WEN, PENG BI-XIAN
    1989, 7(3):  68-72.  DOI: 10.7517/j.issn.1674-0475.1989.03.68
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    In present paper the effect of addition of potassium thiocyanate, ammonium thiocyanace, thiourea and urea on the infra-red absorbance intensity and the peak shift of photographic gelatin is investigated. The experiment results show that with the increase of above-mentioned additives the deformation vibration peak intensity of the N-H bond at the wave-number of 1550 cm-1 is weakened, but the peak intensity at 1536 cm-1 is enhanced. The more the additives is added, the stronger the peak intensity at 1536 cm-1. The peak shift from wave-number 1550 cm-1 to 1536 cm-1 is a gradual transition process. When the additive amount exceeds definite value the peak intensity at 1536 cm-1 prevails. All the experimental results elucidate the destroying effect of these additives on the renaturation ability of the gelatin macromolecule in forming the multiple structure.
    STUDIES OF AB INITIO SCF MO AND CONFIGURATION INTERACTION ON THE PHOTOREARRANGEMENT OF NITROMETHANE
    Pu MIN, Yu JIAN-GUO, LIU RUO-ZHITANG
    1989, 7(3):  73-76.  DOI: 10.7517/j.issn.1674-0475.1989.03.73
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    In this paper, the photorearrangement of nitromethane has been studied by ab initio SCF MO and CI (configuration interaction) calculations with STO-3G basis set. Potential energy contours of ground state and some excited states show that it is very difficult for nitromethane to rearrange into methyl nitrite because of the high barriers, either in photoreaction or ther-moreaction. The studies consist of the following steps: Geometries of reactants and products of S0 states and n→π* excited state (S1, T1) were calculated by using gradient method. Transition state (S0) was optimized by minimizing the Euclidean norm of energy gradient. In order to investigate the photorearrangement of nitromethane, we have also calculated the potential contours of S0 state, n→π* excited state (S1, T1) and π→π* excited state (S2, T2) with Cl method along the intrinsic reaction coordinate (IRC) of S0 state. The conclusion we got by analyzing the results of calculation is in agreement with the recent experiment.
    1989, 7(3):  77-80.  DOI: 10.7517/j.issn.1674-0475.1989.03.77
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