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

New asymmetrical/symmetrical styryl cyanines (3a–d,4a–d), monomethine cyanine dyes (5a–d,6a–d) and trimethine cyanine dyes (11a–g,12a–g) 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...

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Bibliographic Details
Published in:Journal of chemical sciences (Bangalore, India) India), 1997-04, Vol.109 (2), p.115-134
Main Authors: Osman, A M, Khalil, Z H, Koraiem, A I M, Abu Elhamd, R M, El-Aal, R M
Format: Article
Language:English
Subjects:
Absorption spectra
Buffer solutions
Charge transfer
Complex formation
Cyanine dyes
Electron transitions
Ethanol
Molecular structure
Solvents
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Summary:New asymmetrical/symmetrical styryl cyanines (3a–d,4a–d), monomethine cyanine dyes (5a–d,6a–d) and trimethine cyanine dyes (11a–g,12a–g) 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.
ISSN:0253-4134
0974-3626
0973-7103
DOI:10.1007/BF02871157