Indium Tin Oxide Electrodes Modified with Tris(2,2‘-bipyridine-4,4‘-dicarboxylic acid) Iron(II) and the Catalytic Oxidation of Tris(4,4‘-di-<i>tert</i>-butyl-2,2‘-bipyridine) Cobalt(II)

Elliott, C. Michael; Caramori, Stefano; Bignozzi, Carlo Alberto

doi:10.1021/la047364f

Cited by 25 publications

(24 citation statements)

References 17 publications

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“…S3).w These catalysts operate with overpotentials ranging from 250 to 500 mV, and controlled potential electrolysis experiments performed in 53 mM TsOHÁH 2 O indicated approximately 75% Faradaic efficiency for the BF 2 -linked catalysts; the H-linked catalysts are far less stable (Table S1). w Chemically modified electrodes were prepared from the carboxylic acid-substituted derivative 7 by heating ITO-coated glass slides in an acetonitrile solution of the complex at 70 1C for 16 h. 13 Variable scan rate cyclic voltammetry experiments revealed a reversible redox couple at À0.46 V vs. SCE (Fig. 2a), coincident with the couple observed for 7 in solution (À0.41 V, Fig.…”

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confidence: 80%

Hydrogen evolution by cobalt tetraiminecatalysts adsorbed on electrode surfaces

2010

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Aryl-substituted tetraimine complexes related to Co(dmgBF 2 ) 2 -(MeCN) 2 (dmg = dimethylglyoxime) were synthesized and are active for hydrogen evolution. Co(dmgBF 2 ) 2 (MeCN) 2 can be adsorbed to a glassy carbon electrode. The chemically modified electrode is active for hydrogen evolution in aqueous solution at pH o 4.5, with an overpotential of only 100 mV.Developing efficient hydrogen evolution catalysts composed of earth-abundant materials is of considerable current interest. 1 Recent work has established that cobalt tetraimine macrocyclic complexes such as Co(dmgBF 2 ) 2 (MeCN) 2 (dmg = dimethylglyoxime) (1) 2 can function as efficient electrocatalysts for the production of hydrogen from protons. [3][4][5] These systems are attractive because they operate at low overpotentials and at potentials that are quite positive relative to previously explored Co and Ni macrocycle systems. Nickelphosphine and cobalt systems pioneered by the DuBois lab are of similar interest. 6 Because the ultimate use of such electrocatalysts in a H 2 -evolving device will likely require grafting them to an electrode surface, we sought to ascertain whether these cobalt catalysts would still function once tethered to an electrode, and how their respective stabilities would be impacted. [7][8][9] Related surface studies have utilized a Nafion membrane to obtain a functional electrode-catalyst system. 10 Derivatization of tetraimine-based macrocycles with the form of 1 is not very versatile due to the metal-templated method used in the ligand's synthesis. We have therefore examined a ligand related to a known Schiff base/oxime tetraimine construct, 11 for which the ligand can be preformed before addition of cobalt. Herein, we report that these tetraimine cobalt complexes can be used to prepare chemically modified electrodes from indium tin oxide (ITO)-coated glass that are active for hydrogen evolution. We moreover establish that 1 is a substantially better hydrogen-evolving catalyst in aqueous solution once attached to a glassy carbon (GC) electrode.Access to various aryl-substituted tetraimine complexes related to 1 was achieved via a two-step synthesis involving initial isolation of the proton-linked glyoxime tetraimine followed by generation of the BF 2 -linked analogue (see Fig. 1 for labeling scheme and ESIw for synthetic details). 12 Solid-state structures were obtained for compounds 3-6 and 8 (Fig. S1).w

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confidence: 80%

Hydrogen evolution by cobalt tetraiminecatalysts adsorbed on electrode surfaces

2010

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“…The photosensitizer [Ru(dcbpy) 3 ]a nd [Fe(dcbpy) 3 ]w ith the same configuration were prepared following literature methods. [25,26] The elemental analyses of C, Ha nd Nw ere performed on aV ario EL III elemental analyzer. 1 HNMR spectra were measured on aV arian INOVA5 00M spectrometer.E SI mass spectra were carried out on aH PLC-Q-Tof MS spectrometer by using methanol as the mobile phase.…”

Section: Methodsmentioning

confidence: 99%

Supramolecular Photoinduced Electron Transfer between a Redox‐Active Hexanuclear Metal–Organic Cylinder and an Encapsulated Ruthenium(II) Complex

Yang

Liu

et al. 2016

Chemistry A European J

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By using redox-active nickel(II) ions as the connect nodes, a hexanuclear metal-organic cylinder (Ni-YL) was achieved through self-assembly with a large cavity and an opening windows capable to accommodate guest molecules. The suitable cavity of Ni-YL provides an opportunity to encapsulate the anionic ruthenium bipyridine derivative [Ru(dcbpy)3] (dcbpy=2,2'-bipyridine-4,4'-dicarboxylic acid) as the photosensitizer for light-driven reactions. The host-guest behavior between Ni-YL and [Ru(dcbpy)3] was investigated by mass spectrometry, NMR spectroscopy, and computational studies, revealing an effective binding of the guest [Ru(dcbpy)3] within the cavity of Ni-YL. Optical experiments suggested a pseudo-intramolecular photoinduced electron transfer (PET) process between the [Ru(dcbpy)3] and the host Ni-YL, leading to an efficient light-driven hydrogen production based on this system. Control experiments with a mononuclear Ni complex as a reference photocatalyst and the inactive [Fe(dcbpy)3] as an inhibitor for comparison were also performed to confirm such a supramolecular photocatalysis process.

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“…In a first study [53] it was demonstrated that ITO and FTO electrodes modified by irreversibly adsorbing a monolayer of Fe(H 2 DCB) 2+ 3 electrocatalyze efficiently the Co(DTB) 2+ 3 oxidation via an EC mechanism. However, while electrogenerated Fe(III) has an ample driving force for oxidizing Co(II), Fe(II) is a thermodynamically too weak reductant for catalyzing Co(III) reduction, and the Fe(II)/(III) couple is of no value for building transparent cathodes.…”

Section: Catalytic Materials For Cathodes Of Dsscsmentioning

confidence: 99%

New Components for Dye-Sensitized Solar Cells

Caramori

Cristino

Boaretto

et al. 2010

International Journal of Photoenergy

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Dye-Sensitized Solar Cells (DSSCs) are among the most promising solar energy conversion devices of new generation, since coupling ease of fabrication and low cost offer the possibility of building integration in photovoltaic windows and facades. Although in their earliest configuration these systems are close to commercialization, fundamental studies are still required for developing new molecules and materials with more desirable properties as well as improving our understanding of the fundamental processes at the basis of the functioning of photoactive heterogeneous interfaces. In this contribution, some recent advances, made in the effort of improving DSSC devices by finding alternative materials and configurations, are reviewed.

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Indium Tin Oxide Electrodes Modified with Tris(2,2‘-bipyridine-4,4‘-dicarboxylic acid) Iron(II) and the Catalytic Oxidation of Tris(4,4‘-di-tert-butyl-2,2‘-bipyridine) Cobalt(II)

Cited by 25 publications

References 17 publications

Hydrogen evolution by cobalt tetraiminecatalysts adsorbed on electrode surfaces

Hydrogen evolution by cobalt tetraiminecatalysts adsorbed on electrode surfaces

Supramolecular Photoinduced Electron Transfer between a Redox‐Active Hexanuclear Metal–Organic Cylinder and an Encapsulated Ruthenium(II) Complex

New Components for Dye-Sensitized Solar Cells

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