Search results for "Catalysis"

Azatruxene‐Based, Dumbbell‐Shaped, Donor–π‐Bridge–Donor Hole‐Transporting Materials for Perovskite Solar Cells

2020

Three novel donor-π-bridge-donor (D-π-D) hole-transporting materials (HTMs) featuring triazatruxene electron-donating units bridged by different 3,4-ethylenedioxythiophene (EDOT) π-conjugated linkers have been synthesized, characterized, and implemented in mesoporous perovskite solar cells (PSCs). The optoelectronic properties of the new dumbbell-shaped derivatives (DTTXs) are highly influenced by the chemical structure of the EDOT-based linker. Red-shifted absorption and emission and a stronger donor ability were observed in passing from DTTX-1 to DTTX-2 due to the extended π-conjugation. DTTX-3 featured an intramolecular charge transfer between the external triazatruxene units and the azo…

Photocatalytic behavior of mixed WO3/WS2 powders

2000

Polycrystalline mixed WO3/WS2 powders have been prepared by different methods. The samples have been characterized by bulk and surface techniques and tested as catalysts for the photodegradation of phenol. The results have indicated that the coupling of WO3 and WS2 leads to an enhanced rate of disappearance of the organic substrate. The effect is explained as the result of the simultaneous electron transfer from WS2 to WO3 and hole transfer from WO3 to WS2. The efficiency of the mixed WO3/WS2 systems strongly depends on the relative amounts of WO3 and WS2 in the various samples. A maximum of photoactivity is obtained when the surface WS2 and WO3 molar fraction is about 0.5.

Cover Picture: Electron Transfer in a Supramolecular Associate of a Fullerene Fragment (Angew. Chem. Int. Ed. 8/2014)

2014

Electron transfer between carbon dots and tetranuclear Dawson-derived sandwich polyanions

2022

Among the photocatalysts which could be used for converting solar energy, polyoxometalates are often regarded as ideal candidates because of their remarkable performances in photocatalytic water splitting and photodegradation of pollutants. Nonetheless, these polyanions are only capable of absorbing UV light, unless coupled to a visible-light photosensitizer. Carbon nanodots are especially promising for this purpose because of their strong visible-light absorption, photostability, non-toxicity, and very low production costs. In this work we demonstrate the possibility of coupling carbon dots to polyoxometalates with different structures, by a simple self-assembly approach based on electrost…

Supermolecular control of charge transfer in dye-sensitized nanocrystalline TiO2 films: towards a quantitative structure-function relationship.

2005

Unusual B4N2C2 Ligand in a Ruthenium Pseudo-Triple-Decker Sandwich Complex Displaying Three Reversible Electron-Transfer Steps

2007

Decreased Electron Transfer Rates of Manganese Porphyrins with Conformational Distortion of the Macrocycle

1998

Slow electron transfer to manganese(iii) porphyrins results when the macrocycle deviates from planarity. This was demonstrated by measuring the kinetics of homogeneous electron transfer from a series of semiquinone radical anions to synthetic manganese porphyrins (shown schematically; R1 =H, Cl, F; R2 =H, F). Three of the four porphyrins studied have nonplanar macrocycles. These results could have implications for the role of manganese in biological electron transfer processes.

Structural and vibrational study of the tautomerism of histamine free-base in solution.

2003

Infrared and Raman spectroscopy in H(2)O and D(2)O and quantum Density Functional calculations were used to determine the structure of histamine free-base in aqueous solution. A quantum mechanical study of the tautomeric equilibrium of histamine free-base in solution was performed at the 6-311G level. Electronic correlation energies were included by using the hybrid functional B3LYP. The solvent was simulated as a continuum characterized by a dielectric constant, and the quantum system (solute) was placed in an ellipsoidal cavity. Solute-solvent electrostatic interaction was calculated by means a multipolar moment expansion introduced in the Hamiltonian. Four relevant histamine conformation…

Most of the field/inductive substituent effect works through the bonds

2019

AbstractAn application of the quantum chemical modeling allowed to investigate the nature of the field/inductive substituent effect (SE). For this purpose, series of X-tert-butyl···tert-butane (TTX) complexes (where X = NMe2, NH2, OH, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, NO) were studied. A starting distance between central carbon atoms in substituted and unsubstituted fragments of TTX, dC1–C4, was the same as the distance C1–C4 in X-substituted bicyclo[2.2.2]octane (BCO), where the SE acts both via bonds and via space. A strength of interaction between substituted and unsubstituted components of TTX was described by deformation and interaction energies. The substituent …

Biomimetic oxidation of pyrene and related aromatic hydrocarbons. Unexpected electron accepting abilities of pyrenequinones

2014

We present a mild catalytic method to oxidize PAHs and, in particular, pyrene. The pyrenediones are much better electron acceptors than benzoquinone in the gas phase and present similar accepting abilities in solution.