Fluorescence lifetime of chlorophyll a in pure and mixed langmuir-blodgett films

Picard, G.; Munger, G.; Leblanc, Roger M.; Sage, R. Le; Sharma, Dinkar; Siemiarczuk, Aleksander; Bolton, James R.

doi:10.1016/0009-2614(86)80165-8

Cited by 19 publications

(12 citation statements)

References 31 publications

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“…Considering a value of 4.9 ns for τ 0 (Picard et al 1986), for both Chla and Chlida in SUV, the bimolecular quenching constants K q (K SV /τ 0 ) were calculated and listed below: The bimolecular quenching constants are higher for Chlida as compared to Chla. Both K q values are close to the value reported for porphyrins freely dissolved in aqueous solutions: K q = (2.3-2.6) × 10 11 M -1 ·s -1 (Ricchelli 1991).…”

Section: Qct Effects On Liposome Lipid Bilayersmentioning

confidence: 99%

Comparative spectroscopic studies on liposomes containing chlorophyll a and chlorophyllide a

Milenković¹,

Barbinta-Patrascu²,

Baranga³

et al. 2013

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Abstract. Chlorophyll a (Chla) and chlorophyllide a (Chlida) -a derivative of Chla, have been incorporated in the lipid bilayers of two types of liposomes, small unilamellar vesicles (SUV) and multilamelar vesicles (MLV). The objective of the present work was to compare the spectral behaviour of Chla and Chlida incorporated in the lipid bilayers and their sensing behaviour at molecular level. The VIS absorption and fluorescence emission presented differences depending on the type of liposomes and inserted pigment, reflecting the different localization of porphyrin macrocycle in the lipid moieties. The temperature dependence of emission anisotropy and fluorescence intensity, for both Chla and Chlida incorporated in DPPC SUV, revealed the presence of different lipid phases. The degree of incorporation of quercetin (QCT) in liposome membrane was studied by using Chla and Chlida as molecular sensors. The fluorescence polarisation data and the fluorescence quenching process provided arguments for the insertion of the QCT at the interface lipid/water, in the vicinity of lipid polar heads and porphyrin macrocycle. The phytyl chain of Chla penetrating in the hydrophobic core of the lipid bilayers is responsible for the observed differences among Chla and Chlida in sensing the lipid phase transition and the fluorescence quenching process induced by QCT.

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Section: Qct Effects On Liposome Lipid Bilayersmentioning

confidence: 99%

Comparative spectroscopic studies on liposomes containing chlorophyll a and chlorophyllide a

Milenković¹,

Barbinta-Patrascu²,

Baranga³

et al. 2013

gpb

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“…The studied porphyrins may experience less of this effect because porphyrin aggregates have short-lived fluorescence lifetime [66] and are in this instance self-assembled. The porphyrin aggregates shorter fluorescence lifetimes may also be because of larger dipole moment surrounding molecules which in turn increase the efficiency of energy transfer [68].…”

Section: Porphyrin Nanorods Characterizationmentioning

confidence: 99%

Porphyrin nanorods-polymer composites for solar radiation harvesting applications

Mongwaketsi

Kotsedi

Nuru

et al. 2014

J. Porphyrins Phthalocyanines

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The interest in exploring porphyrin-based nanostructures for artificial solar radiation harvesting stems from their structural similarity to chlorophylls. In nature, the precise organization and orientation of the chlorophylls result in efficient absorption of light energy. Inspired by these naturally occurring architectures relevant optical studies including the dynamics of intermolecular and intra-molecular processes of the porphyrin nanorods were investigated. The design of artificial light harvesting systems requires several key factors, such as absorption in the UV-visible and nearinfrared wavelengths, energy transfer ability and the selection of light absorbing pigments. Another key factor is the organizational structure through which the components will interact. We attempted to accomplish this by incorporating porphyrin nanorods into polymer matrices and this will also aid in achieving an arrangement where they can be directly used as devices. The nanorods were embedded in a polymeric matrix, using latex technology and electrospinning which gave the possibility of investigating the orientation of nanorods in the polymer. Spectroscopic and microscopic studies were conducted to investigate the optical and morphological properties of the porphyrin nanorods-polymer composites for applications in artificial solar radiation harvesting systems.

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“…Monolayers of the pure DA compounds can be deposited on a solid support. There is evidence that porphyrins 7 and chlorophyll a 5,6,16 form aggregates in the 100% LB films. This aggregation is usually characterized by a broadening of the absorption bands, a red-shift and a broadening of the emission bands and a gradual decrease in the lifetime of the singlet excited state.…”

Section: Films Of the Pure Da Compounds Each Of The Fourmentioning

confidence: 99%

“…One of the useful techniques for building up highly ordered molecular systems is the Langmuir-Blodgett (LB) method. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The application of this method to DA compounds imposes certain requirements on the structure and, hence, synthesis of the compounds. The molecules must be insoluble in water in order to form a monolayer on the water surface and to keep them orientated on the surface.…”

Section: Introductionmentioning

confidence: 99%

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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Fluorescence lifetime of chlorophyll a in pure and mixed langmuir-blodgett films

Cited by 19 publications

References 31 publications

Comparative spectroscopic studies on liposomes containing chlorophyll a and chlorophyllide a

Comparative spectroscopic studies on liposomes containing chlorophyll a and chlorophyllide a

Porphyrin nanorods-polymer composites for solar radiation harvesting applications

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

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