Определение констант скоростей и механизма фотопревращений металлопорфиринов методом решения обратной фотокинетической задачи

The fluorescence kinetics of some substituted Zn- and Mg-porphyrins in solid polymer films upon excitation by two-step-wise rectangular laser pulses and 293 K were investigated by the inverse kinetic problem methods. The experimental non-monotonic kinetic curves were approximated by the simulated ones within the framework of a six-level energy scheme describing the reversible interconversions between the two complexes. The best fit between the experimental and simulated curves was obtained by iterative optimization using the Nelder-Mead algorithm. Based on the statistically estimated values of the rate constants and parameters of the considered models, an interpretation of the observed kinetics was given and the conclusion drawn that the interconversions are caused by the process of reversible extra-liganding of the central metal ion, which occurs in the excited triplet T<sub>1</sub> state.

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In vivo FLUORESCENCE KINETICS OF PHTHALOCYANINES IN A SKIN-FOLD OBSERVATION CHAMBER MODEL: ROLE OF CENTRAL METAL ION AND DEGREE OF SULFONATION

Photochemistry and Photobiology ◽

10.1111/j.1751-1097.1993.tb09554.x ◽

1993 ◽

Vol 58 (2) ◽

pp. 233-237 ◽

Cited By ~ 22

Author(s):

H. L. L. M. Leengoed ◽

N. Veen ◽

A. A. C. Versteeg ◽

R. Ouellet ◽

J. E. Lier ◽

...

Keyword(s):

Metal Ion ◽

Central Metal ◽

Observation Chamber ◽

Fluorescence Kinetics ◽

In Vivo Fluorescence ◽

Skin Fold ◽

Chamber Model ◽

Kinetics Of

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Studies of Oxygen Exchange Between Trivalent Lanthanide – EDTA Complexes and Solvent Water: Evidence for a Structural Change Within the Series

Canadian Journal of Chemistry ◽

10.1139/v73-082 ◽

1973 ◽

Vol 51 (4) ◽

pp. 538-544 ◽

Cited By ~ 7

Author(s):

R. H. Betts ◽

R. H. Voss

Keyword(s):

Half Life ◽

Metal Ion ◽

Oxygen Exchange ◽

Central Metal ◽

Ionic Charge ◽

Solvent Water ◽

Trivalent Lanthanide ◽

Edta Complexes ◽

Normal Water ◽

Kinetics Of

Oxygen-18 labelled EDTA, dissolved in normal water, has been used to examine the kinetics of oxygen transfer between the solvent and a variety of metal–EDTA complexes, including most of the lanthanides, Ca and Th. The lability of the oxygens is profoundly affected by the ionic charge of the metal in the chelate. Thus oxygen exchange in the Th–EDTA–H2O system shows a half-life of 10 min at 100 °C, while for comparable conditions, Ca–EDTA–H2O shows a half-life in excess of 100 days. The lanthanides as a group show behavior intermediate between these extremes. Within the latter group the lability varies systematically with atomic number, Pr–EDTA (element 59) being the most reactive and Yb–EDTA (element 70) the least reactive. The maximum variation across the group is about 10-fold. Interpretation of these results is presented in terms of the polarizing effect of the metal ion on the electron density at the acetate groups. The variation in lability within the lanthanide group can be accounted for quantitatively by changes in coordination number of the central metal ion.

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Influence of the Central Metal Ion on the Desorption Kinetics of a Porphyrin from the Solution/HOPG Interface

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.6b05964 ◽

2016 ◽

Vol 120 (32) ◽

pp. 18140-18150 ◽

Cited By ~ 13

Author(s):

Ashish Bhattarai ◽

Kevin Marchbanks-Owens ◽

Ursula Mazur ◽

K. W. Hipps

Keyword(s):

Metal Ion ◽

Desorption Kinetics ◽

Central Metal ◽

Kinetics Of

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Influence of Trap States on the Kinetics of Luminescence and Induced Light Absorption by Si Nanoparticles in a SiO2 Matrix at Their Excitation with Femtosecond Laser Pulses

Ukrainian Journal of Physics ◽

10.15407/ujpe58.01.0020 ◽

2013 ◽

Vol 58 (1) ◽

pp. 20-25

Author(s):

V.M. Kadan ◽

◽

I.Z. Indutnyi ◽

V.A. Dan’ko ◽

P.E. Shepelyavyi ◽

...

Keyword(s):

Femtosecond Laser ◽

Light Absorption ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Trap States ◽

Sio2 Matrix ◽

Si Nanoparticles ◽

Kinetics Of

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Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19901984 ◽

1990 ◽

Vol 55 (8) ◽

pp. 1984-1990 ◽

Cited By ~ 1

Author(s):

José M. Hernando ◽

Olimpio Montero ◽

Carlos Blanco

Keyword(s):

Aqueous Solution ◽

Metal Ion ◽

Activation Parameters ◽

Enol Form ◽

Kinetics And Mechanism ◽

Kinetic Constants ◽

Steric Factors ◽

Kinetics Of ◽

Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

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Protonation effects on dynamic flux properties of aqueous metal complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2009091 ◽

2009 ◽

Vol 74 (10) ◽

pp. 1543-1557 ◽

Cited By ~ 8

Author(s):

Herman P. Van Leeuwen ◽

Raewyn M. Town

Keyword(s):

Complex Formation ◽

Metal Ion ◽

Good Description ◽

Minor Component ◽

Outer Sphere ◽

Metal Species ◽

Central Metal ◽

Inner Sphere ◽

A Minor ◽

Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

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ChemInform Abstract: KINETICS OF THE METAL ION CATALYZED ESTER HYDROLYSIS OF O-ACETYL DI-2-PYRIDYL KETOXIME

Chemischer Informationsdienst ◽

10.1002/chin.198551084 ◽

1985 ◽

Vol 16 (51) ◽

Author(s):

J. SUH ◽

M. P. SUH ◽

J. D. LEE

Keyword(s):

Metal Ion ◽

Ester Hydrolysis ◽

Kinetics Of ◽

Hydrolysis Of

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Picosecond fluorescence kinetics of the D1-D2-cyt-b-559 photosystem II reaction center complex. Energy transfer and primary charge separation processes

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/s0005-2728(05)80312-3 ◽

1991 ◽

Vol 1060 (3) ◽

pp. 237-244 ◽

Cited By ~ 56

Author(s):

Theo A. Roelofs ◽

Matthias Gilbert ◽

Vladimir A. Shuvalov ◽

Alfred R. Holzwarth

Keyword(s):

Energy Transfer ◽

Photosystem Ii ◽

Charge Separation ◽

Cyt B ◽

Complex Energy ◽

Primary Charge Separation ◽

Separation Processes ◽

Fluorescence Kinetics ◽

Reaction Center Complex ◽

Kinetics Of

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Langevin approach to plasma kinetics with Coulomb collisions

Journal of Plasma Physics ◽

10.1017/s0022377898007363 ◽

1999 ◽

Vol 61 (1) ◽

pp. 89-106 ◽

Cited By ~ 30

Author(s):

M. G. CADJAN ◽

M. F. IVANOV

Keyword(s):

Laser Pulses ◽

Intense Laser ◽

Plasma Parameters ◽

Plasma Dynamics ◽

Coulomb Collisions ◽

Numerical Tests ◽

Langevin Approach ◽

Intense Laser Radiation ◽

Overdense Plasma ◽

Kinetics Of

The Langevin approach to the kinetics of a collisional plasma is developed. Some collision models are considered, and the corresponding stochastic differential equations are derived. These equations can be regarded as an alternative to the description of a plasma in terms of a distribution function. The method developed here allows one to simulate plasma processes, taking account of both collective kinetics effects and Coulomb collisions. Results of the numerical simulation of the intervention of laser pulses with an overdense plasma are presented. The dependence of the absorption coefficient on the plasma parameters is calculated. The features of the plasma dynamics under the action of intense laser radiation are observed and discussed. The results of numerical tests of the validity of this method are also presented.

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