Monomethine Cyanine Dyes Research Articles

Preparation of monomethine cyanine dyes as noncovalent labels for nucleic acids

By condensation of quaternary benzothiazolium, quinolinium and acridinium salts having an active methyl group with 1-(3-bromopropyl)-4-chloroquinolinium or 1-(3-bromo-2-hydroxypropyl)-4-chloroquinolinium salts in the presence of a basic agent such as triethylamine, 8 asymmetric and symmetric monomethine cyanine dyes bearing ω-bromopropyl substituent with one or two positive charges, were synthesized. Additionally, two of the dyes were quaternized with pyridine, and monomethine cyanines with two and three positive charges are prepared. Most of the dyes showed high molar absorptivity (70 000–100 000 l mol −1 cm −1). The acridinium dyes showed broad peaks with lower intensity of 30 000 l mol −1 cm −1. In the presence of nucleic acid in aqueous solutions, a strong enhancement of the fluorescence of these new dyes was observed.

Synthesis and Visible Spectral Behaviour of Some New Photosensitizers: Monomethine, Dimethine, Trimethine, Styryl and Mixed Cyanine Dyes

The new photosensitizers, monomethine, dimethine, trimethine, styryl and mixed cyanine dyes incorporating pyrazolo/oxazole(thiazole) nuclei are prepared; the visible absorption spectra for all the synthesized cyanines were examined in 95% ethanol; structural confirmation is carried out by elemental analysis, IR and 1H NMR spectroscopy.

The synthesis of some bridgehead heterocyclic monomethine cyanine dyes

α-Chloroacteic acid and phenacyl bromide were used as reagents reacting with 8-hydroxyquinoline to form bridgehead heterocycles. Reaction of these heterocycles with equi-or bis-molar ratios of 2-(or 4-)methyl substituted heterocyclic quaternary salts afforded a series of monomethine and bismonomethine cyanine dyes. The electronic spectra of the monomethine cyanine dyes in various solvents are discussed. ©

Preparation of monomethine cyanine dyes for nucleic acid detection

By condensation of quaternary heterocyclic compounds having an active methyl group with 4-chloroquinolinium salts in the presence of basic agents, such as triethylamine, 10 monomethine cyanine dyes with one or two positive charges have been synthesized. Most of the dyes absorb in the region 505–525 nm, two of them in the region around 600 nm, and all dyes have a high molar absorptivity of 50 000–80 000 l mol −1 cm −1. The dyes do not have fluorescent properties in aqueous solution, but in the presence of ds DNA, in most cases a large fluorescence enhancement is observed.

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 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.

Fluorescence spectral characteristics of novel asymmetric monomethine cyanine dyes in nucleic acid solutions

Six new asymmetric monomethine cyanine dyes have been synthesized and their fluorescence characteristics in the presence of nucleic acids studied. The new dyes have no fluorescence of their own in water solutions upon excitation at 480 nm but they become strongly fluorescent in the presence of nucleic acids. The fluorescence maxima of the investigated dyes are found at 525–545 nm when bound to dsDNA and around 600 nm upon binding to RNA and ssDNA. Fluorescence quenching studies with increasing concentrations of NaCl indicate that the cyanine dyes have a mixed (intercalating and groove binding) type of interaction with dsDNA. ©1997 Federation of European Biochemical Societies.

Synthesis of the First Chiral Bisindolyl Monomethinium Cyanine Dyes

AbstractThe synthesis of the chiral monomethine cyanine dyes 8 and 9 starting with the achiral indole 1 is described. Key intermediates are the new chiral Fischer bases R‐ and S‐4, which were separated after diastereomeric salt formation. The conformation of the dyes 8 and 9 is twisted di‐Z, according to NOE and dynamic NMR spectroscopy. The free energy difference between oppositely twisted conformations is ca. 2.5 kJ mol−1.

ChemInform Abstract: Chiral Polymethine Dyes. Part 3. Synthesis and Spectroscopic Properties of an Unsymmetrical, Chiral Monomethine Cyanine Dye with a Thiazolyl and Quinolyl End Group.

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Chiral Polymethine Dyes, III. Synthesis and Spectroscopic Properties of an Unsymmetrical, Chiral Monomethine Cyanine Dye with a Thiazolyl and Quinolyl End Group

AbstractThe synthesis of the unsymmetrical monomethine cyanine dye 6 in its monochiral (6a, b) and isochiral form (6c), first realized by Götze in 1938, has been significantly improved and its spectroscopic properties have been studied. According to the synthetic pathway, the stereogenic center in dye 6 is delivered by monochiral 1‐phenylethylamine.

Monomethine cyanine dyes containing benz[c,d]indole and pyrylium end-groups

Asymmetric monomethine cyanine dyes with benz[c,d]indole and pyrylium end-groups were prepared. The dyes absorb in the region 633–688 nm and are among the most deeply coloured monomethine cyanine dyes containing nitrogen heterocycles synthesized so far. Quantum-chemical considerations show that electronic excitation to the first-singlet-excited state is localized in the polymethine fragment and is connected with a considerable decrease in electronic polarizability.

Condensed heterocyclic compounds containing a thiazole ring. 12. Derivatives of thiazolo[3,4-b][1,2,4]triazine

Unsymmetrical monomethinecyanine dyes, containing a benzothiazole residue, were obtained from thiazolotriazine. To interpret the nature of the main absorption bands and localize the electronic transitions, the transition energies and electronic distribution of the first and second excited states of several model compounds were calculated by the self-consistent field method.

Synthesis, spectral behaviour and biological activity of pyrazolo‐pyrimidine cyanine dyes

AbstractNew asymmetrical 2(4)‐monomethine cyanine dyes (IIIa‐c IVa‐i), monomethine bases (Va,b), dicationic cyanines (VIIIa_c, IXa‐c) and styryl cyanines (XIa‐b) incorporating N‐phenyl‐1‐H‐pyrazolo (3, 4‐d) saturated or unsaturated pyrimidine were prepared. The new cyanines were identified by spectral determination. Bactericidal and fungicidal activity of selected cyanines (IIIa‐c, IVa‐i, Va,bVIIIa‐c, IXa‐c and XIa,b) were tested against bacterial and fungal strains.

Cyanine dyes from polynitro- and poly(trifluoromethylsulphonyl)-benzenes

New monomethine and trimethine cyanine dyes with benzothiazole or indole and polynitro- or poly(trifluoromethylsulphonyl)-substituted benzene rings attached to the ends of the polymethine chain have been synthesised. Atoms of fluorine or methyl groups were introduced to the α-position of the polymethine chain. The influence of nitro and trifluoromethylsulphonyl groups on the colour of these dyes is compared. It is shown that the CF 3SO 2 group is a weaker auxochrome than the nitro group.

The chemical, spectral, and biological properties of monomethine cyanine dyes containing 1,3-benzoxazine and quinazoline nuclei.

The chemical, spectral, and biological properties of monomethine cyanine dyes containing 1,3-benzoxazine and quinazoline nuclei.