Kinetics of Metalloporphyrin Chemisorption onto Monolayer-Confined Ligands and Subsequent Distal Ligand Exchange

Ryswyk, Hal Van; Gabor, R. S.; Awasthi, S.P.; Bodzin, Dena J.; Orosz, Kristina S.

doi:10.1021/la048344g

Cited by 4 publications

(20 citation statements)

References 29 publications

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“…Here, we apply an alternative method for anchoring high-potential zinc–porphyrin sensitizers to TiO 2 . Unlike our previous system, where zinc porphyrins were anchored to TiO 2 nanoparticles via covalently attached carboxylate groups at the meso-position of the porphyrin (Figure a), we now exploit the self-assembly chemistry of metalloporphyrins to N-donor ligands. − In this design, the N-donor ligand is functionalized with an anchoring group that binds TiO 2 and serves as the linker between the dye and the metal oxide surface (Figure b).…”

Section: Introductionmentioning

confidence: 99%

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups

et al. 2013

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Efforts to improve the ease of assembly and robustness of photoanodes for light-driven water oxidation have led to the development of a modular assembly method for anchoring high-potential zinc porphyrins to TiO2 via coordination to surface-bound pyridine linkers. It is essential that the anchoring groups provide strong electronic coupling between the molecular dye and metal oxide surface for optimal electron injection and that they are robust under the operating conditions of the system. Here, four linker molecules functionalized with either carboxylate, phosphonate, acetylacetonate, or hydroxamate anchoring groups are compared for their relative water stability on TiO2. We also report the relative electron injection efficiencies, as measured by terahertz spectroscopy, for high-potential zinc porphyrins coordinated to TiO2 via pyridyl linkers with the series of anchoring groups.

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Section: Introductionmentioning

confidence: 99%

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups

et al. 2013

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“…An alternate strategy − is to form a mixed monolayer from a diluent thiol and a thiol terminated with a functional group or ligand that can subsequently be coupled covalently to the redox species of interest. While this post-adsorption coupling strategy is intrinsically more flexible, no one coupling reaction has yet been broadly adopted.…”

Section: Introductionmentioning

confidence: 99%

Rate of Interfacial Electron Transfer through the 1,2,3-Triazole Linkage

et al. 2006

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The rate of electron transfer is measured to two ferrocene and one iron tetraphenylporphyrin redox species coupled through terminal acetylenes to azide-terminated thiol monolayers by the Cu(I)-catalyzed azide-alkyne cycloaddition (a Sharpless "click" reaction) to form the 1,2,3-triazole linkage. The high yield, chemoselectivity, convenience, and broad applicability of this triazole formation reaction make such a modular assembly strategy very attractive. Electron-transfer rate constants from greater than 60,000 to 1 s −1 are obtained by varying the length and conjugation of the electron-transfer bridge and by varying the surrounding diluent thiols in the monolayer. Triazole and the triazole carbonyl linkages provide similar electronic coupling for electron transfer as esters. The ability to vary the rate of electron transfer to many different redox species over many orders of magnitude by using modular coupling chemistry provides a convenient way to study and control the delivery of electrons to multielectron redox catalysts and similar interfacial systems that require controlled delivery of electrons.

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“…Research on the dye often focuses on increasing the overall light harvesting efficiency to subsequently increase the overall photovoltaic efficiency. [1][2][3][4][5][6][7][8][9][10][11][12] Other molecular features of the dye which affect efficiency include the nature and orientation of the functional group used to anchor the dye to the semiconductor surface, 1,[4][5][6][7][8] the physical and chemical nature of the spacing group between the anchoring functionality and the dye, 1,[8][9][10][11][12][13][14][15][16][17] and the dye molecule itself. [1][2][3][4][5][6][7][8][9][10][11][12] Porphyrins have generated a substantial amount of interest for use as the dye component of a DSSC, often inspired by the light harvesting networks found in plants.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12] Porphyrins have generated a substantial amount of interest for use as the dye component of a DSSC, often inspired by the light harvesting networks found in plants. [8][9][10][11][12][13][14][15][16][17] DSSC dyes are typically dyes where an appropriate oxide binding functionality has been tethered to the dye, such as a carboxylic or phosphonic functional group. [1][2][3][4][5][6]8 These dyes can then be adsorbed onto a semiconductor surface for subsequent photophysical studies and demonstration of charge transfer in a photovoltaic device.…”

Section: Introductionmentioning

confidence: 99%

“…Other attempts to bind porphyrins to TiO 2 have been attempted in a similar manner to this work. [12][13][14][15][16][17] Functional DSSC devices exploiting axial ligation of porphyrins have been prepared, resulting in good photovoltaic behavior for porphyrin DSSC devices. 12,17 Several studies have focused on porphyrin tethering through modification of gold with alkanethiols with long, nonconductive alkyl chains terminated by a pyridine functionalization.…”

Section: Introductionmentioning

confidence: 99%

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Metalloporphyrin Assemblies on Pyridine-Functionalized Titanium Dioxide

Brumbach

Boal²,

Wheeler

2009

Langmuir

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Porphyrin adsorption on TiO2 nanoparticles has been achieved for multiple porphyrins, and in mixed porphyrin assemblies, via axial ligation to surface-bound pyridine anchored by either para carboxylic or phosphonic functionalizations. Homogenous assemblies were prepared and characterized, while mixed metalloporphyrin assemblies were demonstrated by controlling the concentration ratios of respective porphyrins in the modifying solution. Evaluation of the assemblies using spectroscopic techniques and electrochemistry confirms high porphyrin retention, while exhibiting their surface bound optical and electrochemical properties. A thorough study is discussed where several metalloporphyrins have been evaluated (Ru(CO)OEP, Ru(CO)TPP, and ZnTPP) for relative comparisons and relationships to pyridyl axial binding strengths. The systematic study evaluates multiple background cases using either H2TPP, TiO2 modification with benzoic acid, or unmodified TiO2 to confirm the high affinity of Ru and Zn porphyrins for surface-anchored pyridyl sites. The simple method of step-by-step coordinative anchoring of porphyrins to TiO2 using small, commercially available molecules is highly adaptable for use in dye-sensitized solar cells (DSSC) where intimate contact between the absorbing dye and the semiconductor is required. DSSC devices with novel mixed porphyrin assemblies were shown to give higher power performance than DSSCs utilizing sensitization with only one type of porphyrin.

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Kinetics of Metalloporphyrin Chemisorption onto Monolayer-Confined Ligands and Subsequent Distal Ligand Exchange

Cited by 4 publications

References 29 publications

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups

Rate of Interfacial Electron Transfer through the 1,2,3-Triazole Linkage

Metalloporphyrin Assemblies on Pyridine-Functionalized Titanium Dioxide

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Kinetics of Metalloporphyrin Chemisorption onto Monolayer-Confined Ligands and Subsequent Distal Ligand Exchange

Cited by 4 publications

References 29 publications

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO2 with a Series of Anchoring Groups

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO2 with a Series of Anchoring Groups

Rate of Interfacial Electron Transfer through the 1,2,3-Triazole Linkage

Metalloporphyrin Assemblies on Pyridine-Functionalized Titanium Dioxide

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Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups

Modular Assembly of High-Potential Zinc Porphyrin Photosensitizers Attached to TiO₂ with a Series of Anchoring Groups