Enhanced stokes shift of S2→S0 emission and structural investigations of Sn(IV)Porphyrins doped hybrid borate glasses

Venkatramaiah, N.; Ramakrishna, Buthanapalli; Kumar, Aashutosh; Veeraiah, N.; Venkatesan, R.

doi:10.1016/j.jallcom.2011.09.105

Cited by 9 publications

(11 citation statements)

References 26 publications

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“…[20] The difference in energy of the absorption and emission peaks shows as mall Stokes shift of 8nm( Figure 6, top). [21] This corresponds to the literature value for the Stokes shifto fZ n II TPP in acetonitrile. [20] On encapsulation of 1 in the cavity of the cage, the Stokess hift decreases to 5nm, consistent with an increase in the rigidity of the cage structure when its void is filled with ag uest (Figure 6, bottom).…”

Section: Analysis Of the Host-guest Complex By Csi-msand 1 Hnmr Spectsupporting

confidence: 76%

“…On excitation at 550 nm, the empty cage exhibits two emission bands in the range 560–700 nm corresponding to S 1 →S 0 transitions . The difference in energy of the absorption and emission peaks shows a small Stokes shift of 8 nm (Figure , top) . This corresponds to the literature value for the Stokes shift of Zn II TPP in acetonitrile .…”

Section: Fluorescence Quenching Studies On the Cagesupporting

confidence: 73%

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Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Nurttila

Becker

Hessels

et al. 2018

Chemistry A European J

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The design of a biomimetic and fully base metal photocatalytic system for photocatalytic proton reduction in a homogeneous medium is described. A synthetic pyridylphosphole‐appended [FeFe] hydrogenase mimic was encapsulated inside a supramolecular zinc porphyrin‐based metal–organic cage structure Fe4(Zn‐L)6. The binding is driven by the selective pyridine–zinc porphyrin interaction and results in the catalyst being bound strongly inside the hydrophobic cavity of the cage. Excitation of the capsule‐forming porphyrin ligands with visible light while probing the IR spectrum confirmed that electron transfer takes place from the excited porphyrin cage to the catalyst residing inside the capsule. Light‐driven proton reduction was achieved by irradiation of an acidic solution of the caged catalyst with visible light.

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Section: Analysis Of the Host-guest Complex By Csi-msand 1 Hnmr Spectsupporting

confidence: 76%

Section: Fluorescence Quenching Studies On the Cagesupporting

confidence: 73%

Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Nurttila

Becker

Hessels

et al. 2018

Chemistry A European J

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“…This might be the important limitation of our current system based on biomolecular self‐assembly. Interestingly, the FRET emission from 700 nm to 850 nm was not observed in the Fmoc‐FF/SnTPyP hybrid hydrogels, although the Stokes shift emission of Sn‐containing porphyrins is possible over a similar wavelength range according to the literature …”

Section: Methodsmentioning

confidence: 82%

Self‐Assembly of Metalloporphyrins into Light‐Harvesting Peptide Nanofiber Hydrogels for Solar Water Oxidation

Kim

Nam

Lee

et al. 2013

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The use of renewable and clean energy is critically needed for the sustainability of our society since fossil fuels cause serious environmental problems. [ 1,2 ] Solar energy is undoubtedly a promising energy resource, but its use is limited by the low irradiance intensity (about 100 mW/cm 2 ), intermittence, and geographical heterogeneity. Photovoltaic systems have intrinsic limitation in solving these problems because of difficulties in the storage and transportation of electrical energy. In nature, solar energy is converted to chemical energy in green plants, algae, and cyanobacteria via photosynthesis. Enormous efforts have been made to develop an artifi cial photosynthetic system for the production of clean fuels by utilizing solar energy. [3][4][5][6] Water-splitting, however, is a highly challenging reaction because it requires multiple-electron transfer coupled with proton transfer at a minimum potential of 0.81 V versus normal hydrogen electrode (NHE) at pH 7 on average for each electron transfer. [ 7 ] Photosystems overcome this intrinsic limitation using sophisticated protein scaffolds for the optimization of the spatial arrangement of functional molecules, such as catalytic clusters (i.e., Mn complexes), redox relay molecules (i.e., quinone complexes), and chromophores (i.e., chlorophylls), as illustrated in Figure S1 in the Supporting Information. In particular, a well-defi ned spatial alignment of chromophores is critically important for effi cient excitation energy transfer (EET) to the reaction center, so that photosystems effectively generate a gradient of electrochemical potential for photosynthetic reactions. [ 8 ] Thus, it is highly desirable to construct artifi cial light-harvesting complexes for EET. However, the precise assembly of multiple chromophores with redox catalysts is technically very diffi cult, imposing limitations to EET for light-driven water-splitting. [9][10][11][12][13] Herein we report on the application of molecular selfassembly for photochemical water oxidation under visible light. Self-assembled biomolecular nanostructures can serve as a scaffold for the nanoscale arrangement of chromophores to generate a series of Förster-type resonance energy transfer (FRET) events, which increases the delocalization of excitation energy toward catalysts for light-driven water oxidation. [14][15][16][17] Among various self-assembling biomolecules, diphenylalanine (Phe-Phe, FF) was chosen because it is the simplest amino acid motif that can produce unique nanostructures with structural fl exibility and molecular recognition capability. [18][19][20][21][22] The self-assembled FF nanostructures exhibited unparalleled optical, electrochemical, mechanical properties with high stability and biocompatibility. [23][24][25][26] Furthermore, the substitution of diphenylalanine with other amino acids (e.g., glycine) can induce the self-assembly of nanostructures having different properties, demonstrating that the functional set of molecules can be extended simply by the change of amino acids. [ 2...

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“…Due to emission at higher wavelengths λ > 630 nm, these materials are promising photosensitizers for photodynamic therapy of cancer (PDT) [ 1 ], a non-invasive medicine procedure. In addition, positive Stokes shifts (the difference between wavelength values of the Q(0,0) emission band and wavelength of Soret absorption band) around 200 nm are obtained, thus this material makes a clear distinction of the emission from scattered light [ 32 ]. Because of rapid vibronic relaxation from S 2 to S 1 , only the emissions at 610 nm and 720–730 nm were observed and there were no emission peaks near the Soret band.…”

Section: Resultsmentioning

confidence: 99%

Hybrid Materials Based on Silica Matrices Impregnated with Pt-Porphyrin or PtNPs Destined for CO2 Gas Detection or for Wastewaters Color Removal

Anghel

Lascu

Epuran

et al. 2020

IJMS

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Multifunctional hybrid materials with applications in gas sensing or dye removal from wastewaters were obtained by incorporation into silica matrices of either Pt(II)-5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (PtTAOPP) or platinum nanoparticles (PtNPs) alone or accompanied by 5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (TAOPP). The tetraethylorthosilicate (TEOS)-based silica matrices were obtained by using the sol-gel method performed in two step acid-base catalysis. Optical, structural and morphological properties of the hybrid materials were determined and compared by UV-vis, fluorescence and FT-IR spectroscopy techniques, by atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) and by Brunauer–Emmett–Teller (BET) analysis. PtTAOPP-silica hybrid was the most efficient material both for CO2 adsorption (0.025 mol/g) and for methylene blue adsorption (7.26 mg/g) from wastewaters. These results were expected due to both the ink-bottle mesopores having large necks that exist in this hybrid material and to the presence of the porphyrin moiety that facilitates chemical interactions with either CO2 gas or the dye molecule. Kinetic studies concerning the mechanism of dye adsorption demonstrated a second order kinetic model, thus it might be attributed to both physical and chemical processes.

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Enhanced stokes shift of S2→S0 emission and structural investigations of Sn(IV)Porphyrins doped hybrid borate glasses

Cited by 9 publications

References 26 publications

Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Self‐Assembly of Metalloporphyrins into Light‐Harvesting Peptide Nanofiber Hydrogels for Solar Water Oxidation

Hybrid Materials Based on Silica Matrices Impregnated with Pt-Porphyrin or PtNPs Destined for CO2 Gas Detection or for Wastewaters Color Removal

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