Synthesis, characterization and application of a novel polymer solid photosensitizer

Suzuki, Masahiro; Ohta, Yuko; Nagae, Hidetoshi; Ichinohe, Takashi; Kimura, Mutsumi; Hanabusa, Kenji; Shirai, Hirofusa; Wöhrle, Dieter

doi:10.1039/a909406g

“…From the applied point of view, the present work pursues the objective of finding development tools for the design of photo‐sensitizers, particularly for the generation of singlet molecular oxygen, which may be easily removed from the reaction medium. The problem has been addressed by several authors by attaching dyes covalently to polymers, which may be either soluble (11) or insoluble (12) in the current solvent. Though there are examples in the literature on the supramolecular arrangement of multiple dyes on a single supporting material (13), most of the reported cases are based on single, randomly distributed dyes.…”

Section: Introductionmentioning

confidence: 99%

Energy Transfer Among Dyes on Particulate Solids†

Rodríguez¹,

Iriel²,

Román³

2006

Photochem Photobiol

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Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 x 10(-8) mol g(-1), addition of 2.05 x 10(-7) mol g(-1) Pheo largely inhibits aggregation up to nearly 10(-6) mol g(-1) MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Phi = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization.

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“…[4,5] However,i n some cases, this immobilization can lead to ar eduction of the photocatalytic efficiency throughq uenching of the excited states by the polymericm atrix or by shortening the lifetime of the reactive species. [9] Traditionally,p olymer-supported photocatalysts have been based on hydrophobic matrices, whicha re hardly compatible with polar or aqueous environments, [10,11] thus limiting their application to processes performed in organic solvents such as chloroform or dichloromethane.T oa void the use of such nonpolar volatile organic compounds (VOCs), the hydrophilic/hydrophobic balance of the support should be finetuned to increase their compatibilityw ith polar solvents such as water and alcohols. [6][7][8] The support should also facilitate the accessibility of the immobilized speciesf or the reagents and substrates used in the selected solvents.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] The support should also facilitate the accessibility of the immobilized speciesf or the reagents and substrates used in the selected solvents. [9] Traditionally,p olymer-supported photocatalysts have been based on hydrophobic matrices, whicha re hardly compatible with polar or aqueous environments, [10,11] thus limiting their application to processes performed in organic solvents such as chloroform or dichloromethane.T oa void the use of such nonpolar volatile organic compounds (VOCs), the hydrophilic/hydrophobic balance of the support should be finetuned to increase their compatibilityw ith polar solvents such as water and alcohols.…”

Section: Introductionmentioning

confidence: 99%

Rose Bengal Immobilized on Supported Ionic‐Liquid‐like Phases: An Efficient Photocatalyst for Batch and Flow Processes

Valverde

¹

,

Porcar

²

,

Izquierdo

³

et al. 2019

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The catalytic activity of Rose Bengal (RB) immobilized on supported ionic liquid (IL)‐like phases was evaluated as a polymer‐supported photocatalyst. In these systems, the polymer was designed to play a pivotal role. The polymeric backbone adequately modified with IL‐like moieties (supported IL‐like phases, SILLPs) was not just an inert support for the dye but controlled the accessibility of reagents/substrates to the active sites and provided specific microenvironments for the reaction. The structure of SILLPs could be finetuned to adjust the catalytic efficiency of the RB‐SILLP composites, achieving systems that were more active and stable than the related systems in the absence of IL‐like units.

show abstract

“…From the applied point of view, the present work pursues the objective of finding development tools for the design of photosensitizers, particularly for the generation of singlet molecular oxygen, which may be easily removed from the reaction medium. The problem has been addressed by several authors by attaching dyes covalently to polymers, which may be either soluble (1 1) or insoluble (12) in the current solvent. Though there are examples in the literature on the supramolecular arrangement of multiple dyes on a single supporting material (13), most of the reported cases are based on single, randomly distributed dyes.…”

Section: Introductionmentioning

confidence: 99%

Energy Transfer Among Dyes on Particulate Solids

Rodríguez¹,

Iriel²,

Román³

2005

Photochem Photobiol

View full text Add to dashboard Cite

Absorption and fluorescence properties of methylene blue (MB), a well-known singlet molecular oxygen photosensitizer, and its mixtures with pheophorbide-a (Pheo) sorbed on microgranular cellulose are studied, with emphasis on radiative and nonradiative energy transfer from Pheo to MB. Although pure MB builds up dimeric species on cellulose even at 2 x 10(-8) mol g(-1), addition of 2.05 x 10(-7) mol g(-1) Pheo largely inhibits aggregation up to nearly 10(-6) mol g(-1) MB. At the same time, the absorption spectrum of monomeric MB in the presence of Pheo differs from the spectrum in pure cellulose. Both effects reveal a strong influence of Pheo on the medium properties. A model relying entirely on experimental data is developed, through which energy transfer efficiencies can be calculated for thin and thick layers of dye-loaded cellulose. At the largest concentration of MB assuring no dye aggregation, nonradiative energy transfer efficiencies reach a maximum value of nearly 40%. This value is quite high, taking into account the low fluorescence quantum yield of Pheo, Phi = 0.21, and results from the existence of high local concentrations of the acceptor within the supporting material. These results show that large energy transfer rates can exist in a system devoid of any special molecular organization.

show abstract

Synthesis, characterization and application of a novel polymer solid photosensitizer

Cited by 19 publications

References 13 publications

Energy Transfer Among Dyes on Particulate Solids†

Energy Transfer Among Dyes on Particulate Solids†

Rose Bengal Immobilized on Supported Ionic‐Liquid‐like Phases: An Efficient Photocatalyst for Batch and Flow Processes

Energy Transfer Among Dyes on Particulate Solids

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