Effects of molecular organization on photophysical behavior: Steady-state and real-time behavior of chlorophyll-b fluorescence in spread monolayers of dioleoylphosphatidylcholine

Chauvet, Jean-Paul; Agrawal, M. L.; Hug, Gordon L.; Patterson, L. K.

doi:10.1016/0040-6090(85)90444-4

Cited by 14 publications

(5 citation statements)

References 21 publications

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“…The monolayers of the DA compounds were tested in the following series of matrixes: DOPC, Soya PC, EA, SA, SAm, and DPPA. In agreement with the previous studies, ,− the lipids with unsaturated carbon chains form soft layers and have better miscibility with other molecules compared to the lipids with saturated chains. Matrixes such as DOPC, Soya PC, and EA can prevent the intermolecular aggregation and are hence preferable for the preparation of homogeneous films.…”

Section: Resultssupporting

confidence: 92%

Light-Induced Electron Transfer in Pyropheophytin−Anthraquinone Dyads: Vectorial Charge Transfer in Langmuir−Blodgett Films

et al. 1999

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Novel types of donor-acceptor (DA) compounds, consisting of covalently linked pyropheophytinanthraquinone molecules (PQ1 and PQ2) and their Zn derivatives (ZnPQ1 and ZnPQ2) have been previously synthesized and studied in a variety of solvents. The compounds are retaining the chlorophyll phytyl tail, which makes them suitable for the Langmuir-Blodgett (LB) technique. The technique enables one to prepare solid films capable of performing vectorial intramolecular light-induced electron transfer (ET). The DA compounds form stable monolayers on a water surface and the monolayers can be transferred onto a solid substrate. The ET properties of the LB films were tested by means of time-resolved fluorescence spectroscopy and direct transient photovoltaics measurements. In 100% films, an intramolecular ET is strongly reduced as a result of intermolecular aggregation between the DA molecules. To prevent the aggregation, the DA compounds were placed in a matrix of soft lipids (e.g., lipids with unsaturated carbon chains) and methods to achieve uniform deposition of multilayer films were developed. The highest efficiency of the intramolecular ET was obtained for the multilayer films prepared by combining layers of ZnPQ1 in a Soya lipids matrix with dipalmitoylphosphatidic acid as the bottom and intermediate layers. The sign of the signals in the photovoltaics measurements and, therefore, the direction of the ET can be controlled by the deposition direction of the DA active layers.

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Section: Resultssupporting

confidence: 92%

Light-Induced Electron Transfer in Pyropheophytin−Anthraquinone Dyads: Vectorial Charge Transfer in Langmuir−Blodgett Films

et al. 1999

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“…During the past decades there has been a large interest in the properties of supramolecular assemblies, prepared on planar substrata according to the Langmuir−Blodgett technique. − The high local concentration of chromophores in those assemblies promotes molecular aggregation and inter- and intralayer electron and energy transfer. This explains why the singlet excited state of monomers is often quenched by dimers. − While it has been demonstrated that, assuming a certain model for molecular distribution and the kinetics of the energy transfer process, stationary fluorescence experiments allow one to determine the parameters governing the energy transfer, those experiments have only a limited power to discriminate among different models. More recently the photophysical processes occurring in molecular assemblies were investigated by analyzing the fluorescence decays. , However, to the extent that one is limited to the analysis of individual fluorescence decays, this analysis allows only a limited discrimination between different models for the distribution of acceptor sites.…”

Section: Introductionmentioning

confidence: 99%

“…This explains why the singlet excited state of monomers is often quenched by dimers. [4][5][6][7] While it has been demonstrated that, assuming a certain model for molecular distribution and the kinetics of the energy transfer process, stationary fluorescence experiments allow one to determine the parameters governing the energy transfer, those experiments have only a limited power to discriminate among different models. More recently the photophysical processes occurring in molecular assemblies were investigated by analyzing the fluorescence decays.…”

Section: Introductionmentioning

confidence: 99%

Global Analysis of the Fluorescence Decays of N,N‘-Dioctadecyl Rhodamine B in Langmuir−Blodgett Films of Diacylphosphatidic Acids

Ballet¹,

Auweraer²,

Schryver³

et al. 1996

J. Phys. Chem.

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Langmuir-Blodgett multilayer films were prepared from N,N′-dioctadecyl rhodamine B (RB18) diluted in dioleoylphosphatidic acid (DOPA) or dipalmitoylphosphatidic acid (DPPA) with various mixing ratios. Surface pressure-area isotherms of monolayers of the two matrices were recorded. Absorption and fluorescence spectra and fluorescence decays of the multilayer samples of RB18 were further examined. The fluorescence decay curves of RB18 in the multilayer assemblies, determined using time-correlated single photon counting, were analyzed in the framework of several models leading to nonexponential decays: (1) multiexponential decay; (2) Gaussian distribution of rate constants; (3) stretched-exponential decay, characteristic of Förster energy transfer in self-similar fractal-like structures with a fractal dimensionality of <2; and (4) Förster energy transfer in a two-dimensional system accompanied by an unquenched decay. Using the global analysis method, only the decay law for Förster energy transfer in two dimensions accompanied by a monoexponential decay yielded acceptable statistical fits for multilayer assemblies of RB18 and DOPA or DPPA in the concentration range from 0.2 to 5 mol %. While global analysis of nonexponential decay profiles gave adequate parameters over the whole concentration range studied, single-curve analysis yielded less accurate values for the decay parameters, which became physically unacceptable at the highest and lowest dye concentrations studied. For the DOPA multilayer systems the recovered decay parameters suggest a homogeneous distribution of the monomer and dimer molecules. On the other hand, for DPPA multilayer films a demixing leading to a two-phase system is suggested. The phase separation during compression of the mixed DPPA monolayer forms regions where almost exclusively H-like dimers are present and regions where monomers and a small amount of quenching H-like dimers coexist.

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“…One of the most promising approaches to mimic and to understand the functional activity of the biomembrane assembly is a study of interchromophore interactions, distribution?, orientation, conformational changes, mobility and aggregation behavior of macrocyclic compounds within ordered environments. Porphyrin sensitizers incorporated into artificial lipid membranes are quite suitable and reliable model systems for this purpose (9)(10)(11)(12)(13)(14)(15). Previous investigations of porphyrin aggregation have been mostly focused on chromophore-to-lipid ratio dependence (9)(10)(11)(12)(13)(14) analyzing only the initial aggregation state of embedded molecules at a fixed time point (usually just after preparation) without kinetic considerations.…”

Section: Introductionmentioning

confidence: 99%

“…Porphyrin sensitizers incorporated into artificial lipid membranes are quite suitable and reliable model systems for this purpose (9)(10)(11)(12)(13)(14)(15). Previous investigations of porphyrin aggregation have been mostly focused on chromophore-to-lipid ratio dependence (9)(10)(11)(12)(13)(14) analyzing only the initial aggregation state of embedded molecules at a fixed time point (usually just after preparation) without kinetic considerations. Here we report for the first time the aggregation time course for five porphyrins (etioporphyrin [ , which are distinguished mainly by the number and structure of meso-phenyl substituents, in dipalmitoylphosphatidylcholine (DPPC) liposomal membranes.…”

Section: Introductionmentioning

confidence: 99%

Structurally Controlled Porphyrin‐Aggregation Process in Phospholipid Membranes

Borovkov

Anikin

Wasa

et al. 1996

Photochem & Photobiology

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Structurally controlled aggregation course for five porphyrins (etioporphyrin [EP], 5-mono-and 5,lS-di-lp-tolylletioporphyrin [TP and DTP], 5,10,15,20-tetrakislpp-tolyllporphin [TTP], and 5,10,15,2O-tetrakis[3,5-di-tert-b~tylphenyllporphin [TBP]) in dipalmitoyl-phosphatidylcholine liposomes has been monitored by fluorescence and absorption spectroscopy. While TBP shows no tendency to aggregate in liposomes, EP, TP, DTP and TTP form a porphyrin-enriched domain in membrane interior with time. The further aggregation steps within porphyrin clusters resulting in formation of stacked porphyrin aggregates have been observed for EP, TP and DTP.

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Effects of molecular organization on photophysical behavior: Steady-state and real-time behavior of chlorophyll-b fluorescence in spread monolayers of dioleoylphosphatidylcholine

Cited by 14 publications

References 21 publications

Light-Induced Electron Transfer in Pyropheophytin−Anthraquinone Dyads: Vectorial Charge Transfer in Langmuir−Blodgett Films

Light-Induced Electron Transfer in Pyropheophytin−Anthraquinone Dyads: Vectorial Charge Transfer in Langmuir−Blodgett Films

Global Analysis of the Fluorescence Decays of N,N‘-Dioctadecyl Rhodamine B in Langmuir−Blodgett Films of Diacylphosphatidic Acids

Structurally Controlled Porphyrin‐Aggregation Process in Phospholipid Membranes

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