Search results for "photoinduced electron transfer"
showing 7 items of 47 documents
Photoinduced Single Electron Transfer on 5-Aryl-1,2,4-oxadiazoles: Some Mechanistic Investigations in the Synthesis of Quinazolin-4-ones
1999
The photochemistry of some 5-aryl-3-methoxy- (or 5-aryl-3-phenyl-) 1,2,4-oxadiazoles irradiated in the presence of different sensitizers [such as diphenylacetylene (DAC), 9,10-diphenylanthracene (DAN), or triphenylene (TPH)] or ground-state donors such as triethylamine (TEA) has been investigated. Intermediates arising from breaking of the ring O-N bond develop both into quinazolin-4-ones (by a heterocyclization reaction involving the aryl at the C-5 of the oxadiazole nucleus) and into open-chain products (corresponding to a reduction at the ring O-N bond), in different ratios depending on their structures and photoreaction conditions. A reasonable explanation considers sensitization by pho…
ChemInform Abstract: Photoinduced Single Electron Transfer on 5-Aryl-1,2,4-oxadiazoles: Some Mechanistic Investigations in the Synthesis of Quinazoli…
2010
The photochemistry of some 5-aryl-3-methoxy- (or 5-aryl-3-phenyl-) 1,2,4-oxadiazoles irradiated in the presence of different sensitizers [such as diphenylacetylene (DAC), 9,10-diphenylanthracene (DAN), or triphenylene (TPH)] or ground-state donors such as triethylamine (TEA) has been investigated. Intermediates arising from breaking of the ring O-N bond develop both into quinazolin-4-ones (by a heterocyclization reaction involving the aryl at the C-5 of the oxadiazole nucleus) and into open-chain products (corresponding to a reduction at the ring O-N bond), in different ratios depending on their structures and photoreaction conditions. A reasonable explanation considers sensitization by pho…
Thermal and Photoinduced Electron Transfer in Directional Bis(terpyridine)ruthenium(II)–(Bipyridine)platinum(II) Complexes
2013
Metalloligands L1 and L2 consisting of directional bis(terpyridine)ruthenium(II) units and bipyridine moieties were constructed by amide formation. From these metalloligands two Ru–Pt heterobimetallic complexes 1 and 2 were derived by a building-block method by means of platination with [PtCl2(dmso)2]. Both bimetallic complexes 1 and 2 feature metal-to-ligand charge transfer (MLCT) absorptions, and emission occurs at room temperature in fluid solution from 3MLCT(Ru) states in all cases. Energy transfer from platinum to ruthenium is observed in 2 but not in 1 (light harvesting). The one-electron-reduced species [1]– and [2]– were prepared by reduction of 1 and 2 with decamethylcobaltocene. E…
Green-Light Activation of Push-Pull Ruthenium(II) Complexes.
2020
Abstract Synthesis, characterization, electrochemistry, and photophysics of homo‐ and heteroleptic ruthenium(II) complexes [Ru(cpmp)2]2+ (22+) and [Ru(cpmp)(ddpd)]2+ (32+) bearing the tridentate ligands 6,2’’‐carboxypyridyl‐2,2’‐methylamine‐pyridyl‐pyridine (cpmp) and N,N’‐dimethyl‐N,N’‐dipyridin‐2‐ylpyridine‐2,6‐diamine (ddpd) are reported. The complexes possess one (32+) or two (22+) electron‐deficient dipyridyl ketone fragments as electron‐accepting sites enabling intraligand charge transfer (ILCT), ligand‐to‐ligand charge transfer (LL'CT) and low‐energy metal‐to‐ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). Complex 22+ shows 3MLCT phosphorescenc…
Efficient photoinduced electron transfer in a porphyrin tripod-fullerene supramolecular complex via pi-pi interactions in nonpolar media.
2010
A novel porphyrin tripod (TPZn(3)) was synthesized via "click chemistry". Three porphyrin moieties of TPZn(3) are geometrically close and linked by a flexible linker. The electron-transfer oxidation of TPZn(3) results in intramolecular pi-dimer formation between porphyrin moieties as indicated by electrochemical, vis-NIR, and ESR measurements. The cyclic voltammogram of TPZn(3) exhibited stepwise one-electron oxidation processes of three porphyrin moieties in the range from 0.58 to 0.73 V (vs SCE in CH(2)Cl(2)). When TPZn(3) was oxidized by tris(2,2'-bipyridyl)-ruthenium(III) ([Ru(bpy)(3)](3+)), the oxidized species (TPZn(3))(n+) (0n/= 3) exhibited a charge resonance band in the NIR region …
Ultrafast Interface Charge Separation in Carbon Nanodot-Nanotube Hybrids
2021
Carbon dots are an emerging family of zero-dimensional nanocarbons behaving as tunable light harvesters and photoactivated charge donors. Coupling them to carbon nanotubes, which are well-known electron acceptors with excellent charge transport capabilities, is very promising for several applications. Here, we first devised a route to achieve the stable electrostatic binding of carbon dots to multi- or single-walled carbon nanotubes, as confirmed by several experimental observations. The photoluminescence of carbon dots is strongly quenched when they contact either semiconductive or conductive nanotubes, indicating a strong electronic coupling to both. Theoretical simulations predict a favo…
Synthesis, Electrochemistry, and Photophysics of Aza-BODIPY Porphyrin Dyes
2016
International audience; The synthesis of dyad and triad aza-BODIPY-porphyrin systems in two steps starting from an aryl-substituted aza-BODIPY chromophore is described. The properties of the resulting aza-BODIPY-porphyrin conjugates have been extensively investigated by means of electrochemistry, spectroelectrochemistry, and absorption/emission spectroscopy. Fluorescence measurements have revealed a dramatic loss of luminescence intensity, mainly due to competitive energy transfer and photoinduced electron transfer involving charge separation followed by recombination.