Cations acridine

Liu SP, Chen S, Liu ZF et al (2005) Resonance Rayleigh scattering spectra of interaction of sodium carboxymethylcellulose with cationic acridine dyes and their analytical applications. Anal Chim Acta 535 169-175... 

The mechanism of action and incompatibilities of the nondetergent cationic acridine series of antibacterials was studied in detail. 

Photopolymerization reactions are widely used for printing and photoresist appHcations (55). Spectral sensitization of cationic polymerization has utilized electron transfer from heteroaromatics, ketones, or dyes to initiators like iodonium or sulfonium salts (60). However, sensitized free-radical polymerization has been the main technology of choice (55). Spectral sensitizers over the wavelength region 300—700 nm are effective. AcryUc monomer polymerization, for example, is sensitized by xanthene, thiazine, acridine, cyanine, and merocyanine dyes. The required free-radical formation via these dyes may be achieved by hydrogen atom-transfer, electron-transfer, or exciplex formation with other initiator components of the photopolymer system. 

In this work hybrid method is suggested to determine anionic surfactants in waters. It is based on preconcentration of anionic surfactants as their ion associates with cationic dyes on the membrane filter and measurement of colour intensity by solid-phase spectrophotometry method. Effect of different basic dyes, nature and hydrophobicity of anionic surfactants, size of membrane filter pores, filtration rate on sensitivity of their determination was studied. Various cationic dyes, such as Methylene Blue, Crystal Violet, Malachite Green, Rhodamine 6G, Safranin T, Acridine Yellow were used as counter ions. The difference in reflection between the blank and the sample was significant when Crystal Violet or Rhodamine 6G or Acridine Yellow were used. 

Methyl propiolate and pyridine give a rather unstable 2 1 molar adduct which is the 1,2-dihydropyridine (112). The reaction sequence proposed to account for its formation is identical in principle to a similar scheme proposed earlier in the acridine series (Section II,A,2) and is also supported by the observation that the 1-benzoyl-pyridinium cation with the phenylacetylide anion yields (113). ... 

Like acridine, phenanthridine and dimethyl acetylenedicarboxylate in methanol give a high yield of 1 1 1 molar adduct. Ultraviolet absorption spectrum comparisons show that this is best formulated as 9,10-dihydro-9-methoxy-10- (tran.s-l,2-dimethoxycarbonylvinyl) phenanthridine (142) rather than the corresponding phenanthridinium methoxide (143) under neutral conditions acidification changes the spectrum to that characteristic of the phenanthridinium cation. Crystallization of the adduct (142) from methanol containing 5-15% of water gave the betaine [(144) the positions of the ester and carboxylate groups have not been established], while in the presence... 

The resonating positive charge in Dobner s violet is formed not by internal ionization but rather by external ionization. Other colored cations of this general type are numerous the cation of acridine yellow, for example, can be ascribed the structure... 

In other cases the activity ofthe drug is due to the ionized molecule. For example, with the antibacterial acridine dyestuffs it is the cation which is the active agent and factors favouring ionization, all other things being equal, enhance their antibacterial activity (see Chapter 12). 

The rate constants for these relatively short range hole transfer reactions generally decrease exponentially with distance. Yet, characterizing these DNA-mediated reactions with the parameter (3 is a simplification and is certainly inappropriate in cases where the Frank-Condon factor varies with distance (such as has been observed for the acridine photooxidant). Keeping these limitations in mind, however, /i-values for DNA-mediated hole transfer of -0.6-0.7 A-1 have been suggested using several different oxidant-DNA assemblies (Ap, St, Ap radical cation). 

When acridane 1 is oxidized by dibenzoyl peroxide in propanol/ water in acid or neutral medium, there occurs chemiluminescence whose emission spectrum matches the fluorescence spectrum of acridinium cation (protonated acridine) 2. As radical scavengers have no influence... 

Scheme 3 Acridine cation derivatives Proflavine (5), Acridine Orange (6).

Many brilliantly coloured and tinctorially strong basic dyes for silk and tannin-mordanted cotton were developed in the early decades of the synthetic dye industry. Most of these belonged to the acridine, azine, oxazine, triarylmethane, xanthene and related chemical classes their molecules are usually characterised by one delocalised positive charge. Thus in crystal violet (1.29) the cationic charge is shared between the three equivalent methylated p-amino nitrogen atoms. A few of these traditional basic dyes are still of some interest in the dyeing of acrylic fibres, notably as components of cheap mixture navies and blacks, but many modified basic dyes were introduced from the 1950s onwards for acrylic and modacrylic fibres, as well as for basic-dyeable variants of nylon and polyester [44] ... 

Fig. 10.46. Principles of optodes using a neutral carrier (e.g. valinomycin for K+) coupled to an amphiphilic fluorophore (A) an amphiphilic pH indicator (Seiler K. et al. (1989) Anal. Sci. 5, 557). (B) a fluorescent cationic surfactant (e.g. dodecyl acridine orange) (Kawabata Y. et al. (1990) Anal. Chem. 62, 2054).

Whereas in acetonitrile the rate limiting step is an opening of the solvent shell of a reactant, in benzonitrile the back reaction of (5) between the protonated acridine orange cation (BH ) and the 3-methyl-4-nitrophenolate ion (A ) to form the ion pair is diffusion controlled (although the overall reaction to the neutral molecules is an endothermic process). Because of its lower dielectric constant than acetonitrile, the electrostatic interactions between reactants in benzonitrile outweigh specific solvent effects. In other words, in benzonitrile a rate limiting coupling of proton transfer to the reorientation of solvent dipoles does not occur and the measured rates are very fast. The ion recombination (I) + (II) in benzonitrile has a diffusion controlled specific rate (theoretical) k = 9 -1 -1... 

Oxidation of acridine in anhydrous acetonitrile leads to a dimer 65 formed by reaction of the nitrogen in one molecule of the substrate with the point of highest positive charge density in a radical-cation [208]. Anodic oxidation of neat pyridine... 

Both quinoline and isoquinoline molecular ions lose HCN to yield radical cation (109), while loss of HCN from acridine gives structure (110) (B-71MS364). 

An example of disproportionation to (109) and (110) is provided by the behaviour of the berberinium ion in alkaline solution (Scheme 62). The pseudobase of the 5-methyl-phenanthridinium cation is present even in neutral solution (equation 85). Attack at position 9 in acridinium salts is also very easy, and they rearrange to pseudobases in a few minutes in alkaline solution. These pseudobases, unlike the others described, do not undergo ring opening. They readily disproportionate or are oxidized to acridin-9-ones by air when the starting salt is unsubstituted at C-9 (B-78MI20502). Pyridine 1-oxides and their analogues... 

Several dyes have been found to sensitize the cationic polymerization of cyclohexene oxide, epichlorohydrin, and 2-chloroethyl vinyl ether initiated by diaryliodonium salts (109,110). Acridinium dyes such as acridine orange and acridine yellow were found to be effective sensitizers. One example of a benzothiazolium dye (setoflavin T) was also reported, but no other class of dye nor any other example of a dye absorbing at longer wavelengths were discovered. Crivello and Lam favored a sensitization mechanism in which direct energy transfer from the dye to the diaryliodonium salt occurred. Pappas (12,106) provided evidence that both energy transfer and electron transfer sensitization were feasible in this system. 

One very intriguing work on benz[c]acridines and benzo[a]phenothiazines establishes a connection between their carcinogenicity and radical production (Kurihara et al. 1998). It would be interesting to check for a connection between the carcinogenicity and electron structures of the corresponding cation radicals too. 

Basic (cationic) dyes contain cationic groups which are ionized in the dyebath. They are applied to acrylics, nylon, polyester, and paper and are most often azo, anthraquinone, triarylmethane, quinoline, thiazine, methine, oxazine, and acridine types. 

Cationic (Basic) Dyes. These water-soluble cationic dyes are applied to paper, polyacrylonitrile (e g. Dralon), modified nylons, and modified polyesters. Their original use was for silk, wool, and tannin-mordanted cotton when brightness of shade was more important than fastness to light and washing. Basic dyes are water-soluble and yield colored cations in solution. For this reason they are frequently referred to as cationic dyes. The principal chemical classes are diazahemi-cyanine, triarylmethane, cyanine, hemicyanine, thiazine, oxazine, and acridine. Some basic dyes show biological activity and are used in medicine as antiseptics. 

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