Laccases attract attention due to their potential for manufacturing pharmaceutical intermediates from a wide array of phenolic and non-phenolic substrates that are sparingly soluble in water. Because of the high polarity of ionic liquids (ILs), they can dissolve polar and nonpolar compounds and are claimed as "green" alternative for volatile organic solvents. The main aim of this work was to fi...

Central to major advances in biochemical assays, molecular sensor technologies, and molecular optical imaging are fluorescent materials that provide high detection sensitivity for molecular processes. In biological optical imaging, the low tissue autofluorescence and the deep penetration of light into the tissues observed at wavelengths between 650 and 900 nm allow the use of near-infrared (NIR...

Chromic acid oxidation of manumycin (1), an antibiotic produced by Streptomyces parvulus (strain Tü 64), led to the isolation of 2-(2-methyl-4-oxo-2-pentenoylamino)-5,6-epoxy-1,4-benzoquinone (3) and (-)-(R)-2-methylhexanoic acid (4). From the absolute configuration of 4, determined by comparing its optical rotation with published data, follows the absolute configuration at the center of chiral...

Synthesis and characterization of a polymethine cyanine near-infrared (NIR) fluorophoric label for the derivatization and determination of fatty acids separated by capillary electrophoresis are described. The label contains an aromatic amine functionality, which is used to form a covalent linkage with the analyte. Various linking chemistries are explored, including direct amine–acid condensatio...

Cyanine borate (R(Ph)3B-; R alkyl) salts dissolved in non-polar solvents exist predominantly as ion pairs. Irradiation of the ion pair with visible light absorbed by the cyanine leads to formation of a locally excited singlet state of the dye. The singlet excited cyanine in the ion pair is capable of oxidizing the borate anion to the boranyl radical (R(Ph)3B.) The rate constant for this electro...

A selective optical sensor based on immobilization of Eriochrome Cyanine R for the determination of Al(III) ions in aqueous solution has been developed. The method is based on the spectrophotometric measurement of complex Eriochrome Cyanine R-aluminium at 537 nm. The sensing membrane is made of a triacetylcellulose film containing Eriochrome Cyanine R colorimetric reagent immobilized as an ion ...

Studies on a series of polymethine cyanine dyes and analogs (1-24) show that certain near-infrared cyanines are capable of damaging DNA in the absence of light and external reducing agents. Experimental results imply that in this DNA thermal cleavage, the cyanine reduces Cu(II) to Cu(I) which reacts with O2 to generate the reactive oxygen species (ROS) O2 ∙and ∙OH. The formation of these ROS is...

Small molecules interacting with DNA is an emerging theme in scientific research due to its specificity and minimal side-effect. Moreover, a large amount of research has been done on finding compounds that can stabilize G-quadruplex DNA, a non-canonical secondary DNA structure, to inhibit cancerous cell proliferation. G-quadruplex DNA is found in the guanine-rich region of the chromosome that h...

Cyanine dyes have been shown to undergo reversible photoswitching, where the fluorophore can be switched between a fluorescent state and a dark state upon illumination at different wavelengths. The photochemical mechanism by which switching occurs has yet to be elucidated. In this study, we have determined the mechanism of photoswitching by characterizing the kinetics of dark state formation an...

Heptamethine cyanines are important near-IR fluorophores used in many fluorescence applications. Despite this utility, these molecules are susceptible to light-promoted reactions (photobleaching) involving photochemically generated reactive oxygen species (ROS). Here, we have sought to define key chemical aspects of this nearly inescapable process. Near-IR photolysis of a model heptamethine cya...