Design and photochemical study of supramolecular donor–acceptor systems assembled via metal–ligand axial coordination

Kc, Chandra B.; D’Souza, Francis

doi:10.1016/j.ccr.2016.05.012

Cited by 178 publications

(111 citation statements)

References 112 publications

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“…In addition, the cation and anion radical peaks at their expected wavelength region were observed. The magnitude of k CS indicated fast charges eparation, whilet he k CR waso ne-to-two orders of magnitude smaller than k CS ,atrend predicted for fullerene based donor-acceptor systems, [13][14][15][16][17][18][19][20][21][22][23][24][25] andt he expected solventp olarity trends within the experimentale rrors. Such analysisc learly revealed SubPcC + peak in the 660 nm range and C 60 C À peak at 1005 nm, confirming chargeseparation from 1 SubPc* in these dyads.T he transient spectrald ata for dyads 1-5 in DCB is shown in Figure S3 in the Supporting Information, which also confirms charges eparation in this solvent.…”

Section: Transient Absorption Studiesmentioning

confidence: 70%

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Lim

D’Souza

2016

Chemistry A European J

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Subphthalocyanine (SubPc), a unique ring-reduced member of the common phthalocyanines family, although known for its higher absorptivity, reveals narrow absorption with peak maxima around 570 nm thus limiting its utility in light-energy-harvesting applications. In the present study, by peripheral thio-aryl substitution of SubPc macrocycle, the spectral properties have been modulated to extend the absorption and emission well into the visible/near-IR region. Additionally, for α-ring-substituted derivatives, facile oxidation of SubPc was witnessed, thus making these derivatives better electron donors. Next, the preparation of donor-acceptor dyads containing the well-known electron acceptor C60 connected to the central boron atom of SubPc was accomplished by making use of the 1,3-dipolar cycloaddition reaction. Control experiments and free-energy calculations using the redox and spectral data suggested that the observed fluorescence quenching of SubPc in these dyads is due to electron transfer. Accordingly, transient spectral studies performed both in polar and nonpolar solvents conclusively proved electron transfer to be the quenching mechanism in these dyads. The measured rate constants by fitting kinetic data revealed efficient charge separation and charge recombination processes, suggesting that these dyads could be useful materials for the construction of light-to-electricity or light-to-fuel production devices.

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Section: Transient Absorption Studiesmentioning

confidence: 70%

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Lim

D’Souza

2016

Chemistry A European J

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“…Av ariety of electron donor-acceptor ensembles connected by covalent and non-covalent bonds have so far been designed and synthesized to model the light-harvestinga nd charge-separation functions in photosynthetic reaction centers (RCs) of PSI and PSII. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] When the lifetimeso fC Ss tates of the model compounds for photosynthetic reaction centerare as comparably long as those in the photosynthetic reaction centeri n frozen media, fast bimolecular back electron transfer between the charge-separated molecules by diffusioni ns olution has indeedb een observed to shortent he apparent lifetimes of the CS states. [52][53][54][55] Immobilization of photosynthetic reaction center model compounds, which preventst he bimolecular deactivation,i sr equired for development of photonic devices, such as photovoltaic devices.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

2018

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In the homogenous phase, redox catalysts are often deactivated by bimolecular reactions. For example, the charge‐separated state of photoredox catalysts decayed via bimolecular back electron transfer reactions between the charge‐separated molecules to decrease the lifetimes of the catalytically active species. When photoredox catalysts are immobilized on solid supports, the lifetime of the charge‐separated state was remarkably elongated to enhance the photocatalytic activity. Immobilization of photoredox catalysts on electrodes is required for photocurrent generation, leading to development of solar cells. Metal‐oxygen intermediates, which are active for oxidation of various substrates including water oxidation, are also deactivated via bimolecular reactions to produce inactive forms such as dinuclear metal bis‐μ‐oxo complexes. Immobilization of metal complex catalysts on solid supports prohibits the bimolecular deactivation, enhancing the catalytic activity and stability. This Review focuses on recent development of immobilization of both organic and inorganic molecular catalysts on various supports for enhancement of the catalytic activity, selectivity and stability in thermal and photoinduced redox reactions.

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“…[32][33][34][35][36][37][38] When connected to appropriate electron/energy donor/acceptor entitiest hey reveal photoinduced electron/energy transfer. For efficient light capture, porphyrins,p hthalocyanines, dipyrromethenes (BODIPYs), and polypyridyl metal complexes have been commonly used.…”

Section: Introductionmentioning

confidence: 99%

Strongly Coupled Oxasmaragdyrin–BF₂ Chelated Dipyrrin Dyads: Syntheses, X‐ray Structure, Ground‐ and Excited‐State Charge‐Transfer Interactions

Gobeze

Kumar

D’Souza

et al. 2016

Chemistry A European J

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Oxasmaragdyrin (osm), a 22-π electron aromatic macrocycle containing four pyrroles and a furan ring connected by three methine bridges and two direct bonds is shown to be an excellent electron donor-sensitizer exhibiting adequate spectral and redox properties. Further, this novel heterocyclic macromolecule has been utilized in building donor-acceptor systems involving BF -chelated dipyrromethenes (BODIPYs). The osm-BODIPY dyads were fully characterized by optical, electrochemical, computational, and X-ray diffraction studies. Due to close proximity and electronic structure of the donor and acceptor entities, strong intramolecular charge-transfer interactions in these dyads was witnessed and was supported by computational studies. Solvent-polarity-dependent rapid charge separation and charge recombination in these dyads is witnessed from photochemical studies involving time-resolved emission and femtosecond transient absorption studies. The present studies bring out the importance of oxasmaragdyrin as an electron donor in light-energy-harvesting artificial photosynthesis model systems.

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Design and photochemical study of supramolecular donor–acceptor systems assembled via metal–ligand axial coordination

Abstract: Please cite this article as: Chandra B. KC, Francis D'Souza, Design and photochemical study of supramolecular donor-acceptor systems assembled via metal-ligand axial coordination, Coordination Chemistry Reviews (2016), http://dx.doi.org/

Cited by 178 publications

References 112 publications

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

Strongly Coupled Oxasmaragdyrin–BF₂ Chelated Dipyrrin Dyads: Syntheses, X‐ray Structure, Ground‐ and Excited‐State Charge‐Transfer Interactions

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Design and photochemical study of supramolecular donor–acceptor systems assembled via metal–ligand axial coordination

Abstract: Please cite this article as: Chandra B. KC, Francis D'Souza, Design and photochemical study of supramolecular donor-acceptor systems assembled via metal-ligand axial coordination, Coordination Chemistry Reviews (2016), http://dx.doi.org/

Cited by 178 publications

References 112 publications

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Tuning Optical and Electron Donor Properties by Peripheral Thio–Aryl Substitution of Subphthalocyanine: A New Series of Donor–Acceptor Hybrids for Photoinduced Charge Separation

Immobilization of Molecular Catalysts for Enhanced Redox Catalysis

Strongly Coupled Oxasmaragdyrin–BF2 Chelated Dipyrrin Dyads: Syntheses, X‐ray Structure, Ground‐ and Excited‐State Charge‐Transfer Interactions

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Strongly Coupled Oxasmaragdyrin–BF₂ Chelated Dipyrrin Dyads: Syntheses, X‐ray Structure, Ground‐ and Excited‐State Charge‐Transfer Interactions