Spectral, luminescent, and lasing characteristics of chromene dyes and their julolidine analogs emitting in the red spectral range are investigated experimentally and theoretically. It is shown that the cause for a low lasing efficiency of oxochromene compared with iminochromene is a high intersystem crossing to the T 1 state and the presence of the induced T 1→T n absorption in the region of the luminescence band.

The results from investigating the photophysical properties of new coumarin dyes synthesized and incorporated into Langmuir-Blodgett films are presented. A method for forming monolayers on the surface of a water/air interface is proposed. The phase states of mixed monolayers on a water surface are studied. It is found that mixed monolayers of amphiphilic polyampholyte and dye allow us to obtain more stable and condensed films, relative to films of single components. The spectral and luminescent properties of synthesized dyes in solution and in Langmuir-Blodgett films are studied.

Приведены результаты исследования фотофизических свойств новых синтезированных кумариновых красителей, включенных в пленки Ленгмюра–Блоджетт. Предложена методика формирования монослоев на поверхности раздела фаз вода–воздух. Изучены фазовые состояния смешанных монослоев на поверхности воды. Установлено, что смешанные монослои амфифильного полиамфолита и красителя позволяют получать более стабильные и конденсированные пленки по сравнению с пленками индивидуальных компонентов. Исследованы спектральные и люминесцентные свойства синтезированных красителей в растворе и в пленках Ленгмюра–Блоджетт.

A series of zinc and aluminum phthalocyanines containing 3–8 pyridiniomethyl or cholinyl substituents on average were synthesized. As the number of cation substituents increased, in aqueous solutions, the aggregation ability of phthalocyanines decreased, while the quantum yields of fluorescence and singlet oxygen generation increased. The photodynamic inactivation of coliform bacteria sensitized by zinc and aluminum phthalocyanine polycations with an increase in the substitution degree became more effective.

Spectral and protolytic properties of two hydrophobic rhodamine dyes and fluorescein n-decyl ester were studied in Langmuir-Blodgett films based on a polyamido acid. The possibility of weakening the concentration quenching of rhodamine dye fluorescence with a polymeric matrix was demonstrated.

Spectral and protolytic properties of two hydrophobic rhodamine dyes and fluorescein n-decyl ester were studied in Langmuir Blodgett films based on a polyamido acid. The possibility of weakening the concentration quenching of rhodamine dye fluorescence with a polymeric matrix was demonstrated.

Spectral and luminescent properties were studied for chemical dimers and molecular aggregates of Nile Red oxazine dye in solutions. Chemical bonding of two oxazine dye molecules leads to the formation of a dimer whose spectral behavior is in close agreement with the exciton model constructed for “physical” molecular aggregates. Chemical dimers luminesce, whereas dimers formed because of van der Waals interactions do not.

We report the investigation findings of monolayers behaviour of nile red new synthesized amphiphilic analog at the air/water interface and its spectral-luminescent properties in solvents of various polarity and in Langmuir-Blodgett films consisting of dyes and stearic acid mixture. It is shown, that electronic absorption spectra of films depends on the presence of two monomer types of various spatial conformations. The position of the films fluorescence band is identical to a case of polar medium.

The quantum yields for the photosensitized formation of singlet oxygen in air-saturated solutions of rhodamine 123 and its mono-, di, and tetrabromo derivatives in water and ethanol were measured. The solubility of the dyes in these media and the spectral and luminescence characteristics of the solutions were studied. It was shown that, of mono-, di-, and tetrabromo-rhodamines, tetrabromorhodamine 123 is most efficient in generating singlet oxygen. The bromination results in a decrease in the solubility and small (2-3 nm per bromine atom) bathochromic shifts of the absorption and fluorescence spectra.

The behavior of monolayers of a new synthetic amphiphilic analogue of Nile red at the water/air interface and the spectral-luminescent properties of the dye in solvents with various polarities and of its Langmuir-Blodgett films with stearic acid were studied. According to the electronic absorption spectra, monomers of two types with different spatial conformations were present in the films. The fluorescence band of the films coincided with that of the dye in polar media.

The properties of micellar solutions of over 20 colloidal surfactants (including 9 anionic) as media for protolytic reactions were studied with the help of acid-base indicators, mainly of the two-step, or ‘bifunctional’, Decyl Fluorescein (HR ⇄ HR ⇄ R) and of the Reichardt betaine dye, 2,6-diphenyl-4-(2,4,6-triphenylpyridinio-1) phenoxide, with solvatochromic zwitterionic form R (HR ⇄ R + H), as well as of other dyes, completely bound to micelles. The validity of the traditional electrostatic model was tested on the basis of the ‘apparent’ , which describes the dissociation of the indicator, . The object of analysis were alterations in the values, caused by the transfer from water to micellar solutions , from one surfactant to another, and through the variation in the composition of salt background (inorganic and organic ions). The main assumptions of the common electrostatic model – (1) constancy of the ‘intrinsic’ contribution to the value of the given indicator in any micellar system, (2) constancy of the value of the electrical potential of the Stern layer Ψ of the given micellar surface obtained by using any indicator, and (3) the possibility of complete description of salt effects with the help of ion-exchange model, – are shown in most cases to be justified only approximately, and sometimes even insufficiently. Up-to-date attempts to modify the simple electrostatic model are shown to be rather arbitrary. The values in nonionic micelles cannot be considered to be an optimal model of in ionic micelles. That is why the possibility of using the values in micellar solutions of a zwitterionic surfactant CHN(CH)–(CH)–SO as values of the corresponding dyes in micelles of ionic surfactants is discussed. The micellar transitions caused by salts became evident in the case of hydrophobic counterions. The analysis of the values revealed the greatest hydration of the Stern region of anionic micelles as compared with other micellar surfaces. This is in agreement with their values, as well as with other solvatochromic scales. The nature of ionic pairs formed by dye ions and oppositely charged surfactant head groups is discussed. The differentiating action of micellar pseudophase upon the acid-base properties of indicator couples of various charge types and nature, i.e. the disparity in their values, manifests itself distinctly, depending on the nature of the surfactant. This effect is caused, on the one hand, by the miscellaneous character of any micellar surface, and on the other hand – by the dissimilarity among hydrophilic portions of cationic, anionic, nonionic (with oxyethylene chains), and zwitterionic surfactants, as well as of the Stern region of ionic micelles containing counter-ions of different hydrophobicity. The differentiating impact of micelles seems to be the main hindrance to exact evaluations of the interfacial electrical potential of micelles by means of acid-base indicators.

Protolytic equilibria of twenty chromophoric acid–base indicators from different classes, namely, sulfophthaleins, hydroxyxanthenes, azo compounds, and others, were studied in direct microemulsions of benzene–pentanol-1–surfactant–water at volume fractions of the dispersed phase of up to 13%. Cetylpyridinium chloride, sodium dodecylsulfate, and certain nonionic surfactants were used. Apparent acidity constants (p K a ) of indicators were determined under the conditions of their complete binding by microdroplets (p K a ac ). The strong differentiating effect of the dispersed phase of microemulsions of different types on the acid–base properties of indicators was revealed. The effect of the ionic strength of the continuous phase (0.025–1.0) on the values of p K a ac was studied. The partition constants of Bromothymol Blue anions between water and negatively charged microdroplets were estimated. Similarities and differences were revealed in the action of microemulsions and micellar solutions of the corresponding surfactants on the state of the studied chromophoric reagents.

The following ways to modify the properties of the sodium dodecyl sulfate micellar pseudophase were used: (1) variation of NaCl concentrations in the bulk, (2) the complex formation of counter-ions with crown ethers, (3) the replacing of Na+ by Mg2+, accompanied by MgSO4 addition, (4) introduction of a non-ionic surfactant Tween 80 and of 1-pentanol. The apparent ionization constants, Kaa, of hydrophobic indicator decyl eosin (HR⇄R−+H+) were determined in micellar solutions under the mentioned conditions. All these additions were shown to reduce the pKaa, which was interpreted as being caused by the electric potential of the Stern layer growing more positive. The effects observed were compared with those registered earlier with the help of hydrophobic coumarin and cationic indicators; the reasons of diversities appearing in some cases are explained.

The behavior of monolayers prepared from amphiphilic derivatives of fluorescein, eosine, and Rhodamine C at a water-air interface was examined. The conditions of formation of Langmuir-Blodgett films on solid supports were determined. The spectral-luminescent properties of the films were found to depend on the conditions of formation and the structure of the monolayer. The experimental data obtained were interpreted on the basis of quantum-chemical calculations.

The protolytic equilibria of 7 oxyxanthene dyes were studied in 82 wt% aqueous n-butanol, a solvent with low permittivity (ε=20.8) and high molar fraction of water (0.474). The thermodynamic pKa values of fluorescein (pKa0o=1.2, pKa1o=8.5, pKa2o=9.3) and eosin (pKa1o=5.0, pKa2o=8.3), as well as of their ethyl and decyl esters and of sulfonefluorescein were determined at 25°C in the molar concentration scale. On the basis of the absorption spectra of the substances, conclusions were made about the tautomerism of fluorescein and eosin. The values of the tautomeric equilibrium constants and of the microconstants of ionization were calculated. The results are compared with those obtained previously in other solvents.

Studies of the deactivation of the electronic excitation energy of Langmuir-Blodgett (LB) films of two new rhodamines are reported. The main attention is devoted to the establishment of the relation between the structure of multilayer LB films and their luminescent properties. The experimental results are analyzed using quantum-mechanical calculations.

Nitro and amino derivatives of benzo[b]phenoxazine have been synthesized. The spectroluminescence properties of the synthesized compounds are investigated.

A number of new fluorescence compounds suitable as efficient laser dyes for the red spectral region have been synthesized and investigated. The new dyes are distinguished by good solubility in common organic solvents and high photostability. The laser effect of the dyes has been studied by the second harmonic of YAG:Nd3+ laser ((lambda) equals 532 nm) as a pump source. Some of the prepared DCM derivatives and pyridine analogues are efficient laser dyes. Two compounds from a new class of phenalemines possessing good photostability and excellent laser characteristics for the 600-690 nm spectral region are reported for the first time.

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