The structure and vibrational spectra of proton solvates in solution

Yukhnevich, G. V.; Tarakanova, E. G.; Maiorov, V. D.; Librovich, N. B.

doi:10.1070/rc1995v064n10abeh000183

Cited by 68 publications

(11 citation statements)

References 60 publications

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“…In our opinion, introduction of such molecules into a solution must lead to strengthening of the ionization of the solvent, at least in the first coordination sphere. This agrees with the interpretation of the water-base interaction given in [12]. This approach takes into account the mutual influence of the solvent and the test compound.…”

Section: Results Of Calculations and Discussionsupporting

confidence: 76%

Quantum-Chemical Calculations of the Excited Electronic States of the Prodan Molecule and Its Complexes in Water

Artyukhov¹,

Zharkova²,

Morozova³

2005

J Appl Spectrosc

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A quantum-chemical calculation of the prodan molecule and its complexes in water for the geometry of the ground and fluorescent states is carried out. To describe the fluorescent state, changes in the electronic state (population) on bonds and atoms during transition of the molecule into an excited state are taken into account. A model of interaction of the prodan molecule with a polar proton-donor solvent (water) is suggested. It is shown that interaction with the ionic forms (H 3 O + ) provides an explanation for the sensitivity of prodan to the solvent (displacement of the fluorescence bands). The nature of the electronic excited states of the prodan molecule and its complexes has been investigated. The constants of the rates of radiative and nonradiative processes and the fluorescence quantum yields have been calculated.Introduction. Fluorescing organic molecules are widely used in biochemical investigations as probes for studying the physical-chemical properties of solvents, surfaces of various physical nature, large biological molecules, membranes, cells, etc.[1]. In this connection, a molecule of prodan (6-propionyl-2-dimethyl-aminonaphthalene) and its derivatives, for example, a molecule of laurdan (6-dodecanoyl-2-dimethyl-aminonaphthalene), are interesting objects for investigations. In [2][3][4], it was shown that the solvatochromism of laurdan is associated with the considerable change in the dipole moment in excited states. The fluorescence of laurdan in glycerin at a temperature from -15 to +50 o C consists of two bands; at 75 o C it has one band [3]. In the prodan molecule, a fluorochromic effect was observed at room temperature: ν max = 24,940 cm -1 (cyclohexane) and 18,830 cm -1 (water) [5,6].The prodan molecule is a derivative of naphthalene ( Fig. 1) that contains amino-and carbonyl groups. By elongating the CH 2 chain we obtain different derivatives of prodan (prodan at n = 1 and laurdan at n = 10).In the present work, we carried out quantum-chemical investigations of the prodan molecule and its complexes in water. We studied the influence of intermolecular interactions between the prodan molecule and a polar protondonor solvent on the position of electronic states and radiative and nonradiative processes.The sensitivity of the prodan molecule to a solvent is monitored by measuring the displacement of the absorption and fluorescence bands. The properties of this molecule were investigated experimentally in [6,7] in a series of the solvents, the polarity of which differs greatly. On transition from cyclohexane to water, an appreciable displacement of the fluorescence band (6100 cm -1 ) is observed; the maximum of the absorption band in this case is shifted to 1770 cm -1 . The authors note a low quantum yield of fluorescence for the given molecule but do not cite its value. It is pointed out that the quantum yield in a nonpolar solvent is considerably higher than in water [5].Investigation Techniques. The quantum-chemical calculation of the prodan molecule was performed with the aid of a package ...

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Section: Results Of Calculations and Discussionsupporting

confidence: 76%

Quantum-Chemical Calculations of the Excited Electronic States of the Prodan Molecule and Its Complexes in Water

Artyukhov¹,

Zharkova²,

Morozova³

2005

J Appl Spectrosc

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“…We believe, that introduction of such molecules into a solution must lead to an increase in ionization of the solvent, at least, in the first coordination sphere. This is in agreement with the interpretation of the waterbase interaction made in [9]. The author argues that a number of conditions should be met for the PRODAN − Н 3 О + complex to exist: positively charged proton solvates must occur in the solution; the molecules solvating protons should have unshared electron pairs providing symmetric hydrogen bonding; the heat of proton attachment to the molecule should exceed 170 kcal⋅mol -1 .…”

Section: Calculation Results and Discussionsupporting

confidence: 59%

“…It is shown in [9] that there are ionic forms Н 3 О + , Н 5 О 2 + , and Н 9 О 4 + in water, the most stable being H 2 O … H +… OH 2 .…”

Section: Calculation Results and Discussionmentioning

confidence: 98%

Complexing and photoprocesses in a PRODAN molecule

2004

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535.37The effect of hydrogen bond on the spectral-luminescent properties of the PRODAN molecule -water complexes is studied. Quantum chemical calculations are performed for the ground and fluorescent equilibrium states of a free PRODAN molecule and its complexes with Н 3 О + . It is shown that significant changes occur in the geometry of the molecule in the fluorescent state. To describe the fluorescent state, account was taken of the changes in the electron density (population) on the bonds and atoms in transition of the molecule to an excited state. The rate constants of radiative and nonradiative processes and quantum yields of fluorescence are calculated for the PRODAN molecule and its complexes in water. A significant shift of the fluorescent bands (sensitivity to a solvent) in transition of the molecule from cyclohexane to water is accounted for.

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“…The results of quantum-chemical calculations and experimental researches have shown existence of a stable (Н 2 О⋅⋅⋅Н⋅⋅⋅ОН 2 ) + ion with a symmetrical hydrogen bonding [1]. …”

Section: Introductionmentioning

confidence: 98%

<title>Proton solvates in a water environment and their influencing on fluorescent properties of organic molecules</title>

2006

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Some important and essential features of naphthalene derivatives in water environment are studied. Possible interaction centers of investigated molecules with solvent are estimated Possible models of 1-naphthol, 1-naphtholate and prodan complexes in water are offered. The rate constants of photoprocesses and the quantum yield of fluorescence are determined for investigated molecules its complexes with water. Quantum-chemical calculations are performed in the geometry of both the ground and exited states of molecules.

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The structure and vibrational spectra of proton solvates in solution

Cited by 68 publications

References 60 publications

Quantum-Chemical Calculations of the Excited Electronic States of the Prodan Molecule and Its Complexes in Water

Quantum-Chemical Calculations of the Excited Electronic States of the Prodan Molecule and Its Complexes in Water

Complexing and photoprocesses in a PRODAN molecule

<title>Proton solvates in a water environment and their influencing on fluorescent properties of organic molecules</title>

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