Spectroscopic study of the interaction between porphyrin and chlorin molecules of opposite charge in solutions

Losev, A. P.; Nichiporovich, I. N.; Bachilo, Sergei M.; Egorova, G. D.; Volkovich, D. I.; Solov'yo, K. N.

doi:10.1007/bf02606486

Cited by 5 publications

(9 citation statements)

References 7 publications

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“…The positions of the maxima of the Soret and Q-bands in the FB forms of tetra-meso-aryl substituted chlorins are very close to those for the corresponding porphyrins. 20,34 The most pronounced difference in the absorption spectra for this group of porphyrins and chlorins is the increased absorbance of the Q y -band in chlorin derivatives. The visible absorption spectrum of FB TSPC 4consists of four bands centered at 516, 550, 575, and 645 nm.…”

Section: Resultsmentioning

confidence: 99%

“…5,10,15,20-Tetrakis(4-sulfonatophenyl)chlorin (TSPC 4-) was prepared by diimide reduction of the corresponding porphyrin as reported. 20 5,10,15,20-Tetrakis(4-sulfonatophenyl)porphine (TSPP 4-) was purchased from Porphyrin Products (Logan, UT) and used as received. Evans blue (EB) was from Aldrich (Deisenhofer), and bromocresol purple (5,5′-dibromoo-cresol-sulfonaphthalene, BCP) was from Fluka (Buchs, Switzerland).…”

Section: Methodsmentioning

confidence: 99%

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Acid−Base Equilibria in 5,10,15,20-Tetrakis(4-sulfonatophenyl)chlorin: Role of Conformational Flexibility

Kruk¹,

Braslavsky²

2006

J. Phys. Chem. A

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The acid−base equilibria in 5,10,15,20-tetrakis(4-sulfonatophenyl)chlorin were studied in aqueous solution and compared with the respective data for the corresponding porphyrin. The reduction of the pyrrole ring in the tetrapyrrolic macrocycle noticeably influences both free base/monoprotonated and mono-/diprotonated species equilibria. In strong acidic solutions protonation of 4-sulfonatophenyl groups takes place in addition to protonation of the macrocycle core. The photophysical properties of all ionic forms are influenced by an enhanced rate of internal S1 → S0 conversion, leading to about 50% and 90% deactivation through this channel for the free base and diprotonated species, respectively. The enhancement of the rate of the radiationless transitions is explained by an increased conformational flexibility of the chlorin macrocycle with respect to that of a porphyrin. Structural volume change measurements with laser-induced optoacoustic spectroscopy support this explanation. The contraction upon triplet state formation of the free base is about one-half of that measured for the corresponding porphyrin. This contraction should be due to intramolecular structural rearrangements of the macrocycle to adopt a minimum energy conformation in case of the chlorin. On the contrary, for the more rigid porphyrin macrocycle the interactions of the molecule with the solvent environment play a more important role. The diprotonated forms of both porphyrin and chlorin show a high radiationless S1 → S0 conversion rate and seem to have a similar conformational flexibility. In agreement with previous calculations, the conformational flexibility of the diprotonated forms appears to be higher than that of the free base molecule.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Acid−Base Equilibria in 5,10,15,20-Tetrakis(4-sulfonatophenyl)chlorin: Role of Conformational Flexibility

Kruk¹,

Braslavsky²

2006

J. Phys. Chem. A

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“…The molar absorption coefficients of C1 in water in the presence of 10 mM phosphate buffer and C3 in ethanol are ε 660 = 4.0 × 10 4 and ε 640 = 4.3 × 10 4 M cm −1 , respectively. 17,24 For comparison, for chlorin e6 in aqueous solution at pH 8 were λ a = 405 and 640 nm, whereby addition of 5 mM phosphate buffer redshifts λ a to 654 nm. 15 The fluorescence excitation and emission spectra of C2 and C3 in ethanol are shown in Fig.…”

Section: Absorption and Fluorescencementioning

confidence: 99%

“…For comparison, Φ f = 0.18 for both chlorin e6 and C1 in aqueous buffer at pH 8.5. 17 The methylester at positions 13 in C1 and the substituents CH 2-CONHCH 2 (CHOH) 4 CHOH at positions 15 and 17 in C2 have no discernible effect, but the value of Φ f is significantly lower for C2 and C3. A possible origin for this effect might be searched in conformations of the attached chains, possibly quenching ring fluorescence by fast electron transfer reactions.…”

Section: Effects Of Glucose Chainsmentioning

confidence: 99%

“…16 Moreover, other specific spectroscopic effects have been studied. [17][18][19][20][21][22][23][24] Here, the photophysical and photochemical properties of the 13-methylester of chlorin e6 and two derivatives, a 15,17-diglucose derivative and a completely artificial 13,17-diglucose chlorin (C1-C3, respectively) were studied in dichloromethane, as an example of a solvent with medium polarity, and ethanol or acetonitrile as polar solvents. The results were compared with parent chlorin e6 using steady-state and time-resolved photolysis.…”

Section: Introductionmentioning

confidence: 99%

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Photoprocesses of chlorin e6 glucose derivatives

Bauer

Montforts

Losi

et al. 2012

Photochem Photobiol Sci

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The ground and excited state processes of chlorin e6, the monomethyl ester C1, the glucose derivative C2 and the 3-heptylchlorin-glucose C3, were studied in solvents of lower and higher polarity. The excited singlet and lowest triplet states of C1-C3 were characterized by spectroscopic methods for several conditions. The quantum yields of formation of singlet molecular oxygen and the other triplet properties of the three chlorins and chlorin e6 are similar, whereas the fluorescence quantum yield decreases on going from C1 to C3. Time-resolved optoacoustic experiments revealed a ca. 30 kJ mol(-1) higher triplet level for C3 with respect to C1/2.

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Photophysical and Photochemical Processes in Dyad Models of Photosynthetic Reaction Center

Losev¹,

Nichiporovich²,

Тихомиров³

et al. 1995

Spectroscopy of Biological Molecules

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Spectroscopic study of the interaction between porphyrin and chlorin molecules of opposite charge in solutions

Cited by 5 publications

References 7 publications

Acid−Base Equilibria in 5,10,15,20-Tetrakis(4-sulfonatophenyl)chlorin: Role of Conformational Flexibility

Acid−Base Equilibria in 5,10,15,20-Tetrakis(4-sulfonatophenyl)chlorin: Role of Conformational Flexibility

Photoprocesses of chlorin e6 glucose derivatives

Photophysical and Photochemical Processes in Dyad Models of Photosynthetic Reaction Center

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