• A I M Koraiem

      Articles written in Journal of Chemical Sciences

    • Heterocyclic halide moieties in the synthesis and study of some conjugated oxazine methine cyanine dyes

      A M Osman Z H Khalil A I M Koraiem R M Abu Elhamd R M El-Aal

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      New asymmetrical/symmetrical styryl cyanines (3ad,4ad), monomethine cyanine dyes (5ad,6ad) and trimethine cyanine dyes (11ag,12ag) incorporatingbis pyrazolo-[2,3-b;2′,3′-b′] oxazine and/or pyrazolo [2,3-b]-oxazolo [2′,3′-b] oxazine were prepared. The new synthesised cyanines were identified by elemental and spectral analyses. The uv-visible absorption spectra of some selected dyes were investigated in pure and mixed solvents as well as in aqueous buffer solutions. Molecular complex formation with ethanol was verified by mixed solvent studies. Electronic transitions were attributed to either locally excited or predominantly charge transfer states. The spectral shifts were discussed in relation to molecular structure and in terms of medium effects. The variation of absorbance withpH was utilized for the determination of thepKa values for some selected compounds.

    • Synthesis and solvatochromic behaviour of new asymmetrical mono-(tri)-methine cyanine dyes

      R M Abd El-Aal F M Abd El-Latif A I M Koraiem

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      6-Amino-5-cyano-3-methyl-1,4-diarylpyrano[2,3-c]pyrazole derivatives were prepared via the interaction ofα, β-unsaturated nitriles with 3-methyl-1-phenylpyrazol-5-one as starting materials in the synthesis of new asymmetrical mono-(tri)-methine cyanine dyes. The new cyanines were characterised by elemental analysis, IR and1H-NMR spectral data. The visible absorption spectra of some selected dyes were investigated in pure and mixed solvents as well as in aqueous buffer solutions.

    • Studies on some new bridgehead nitrogen heterocyclic cyanine dyes

      A I M Koraiem H A Shindy R M Abu El-Hamd

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      New asymmetrical mono-(tri)-methine and azomethine cyanine dyes of pyrazolo[5,4-b] quinolino [a, b]-1,4-pyra-(oxa)-zinium bromide salts were prepared. The new synthesized cyanines were identified by elemental and spectral analyses. The visible absorption spectra of some selected dyes were investigated in single and mixed solvents, and also in aqueous buffer solutions. The spectral shifts were studied in relation to molecular structure and in terms of medium effects. Molecular complex formation with DMF was verified through mixed-solvent studies.

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