Search results for "PHOTOCHEMISTRY"

Studies in organic mass spectrometry. Part 25. Benzyl ion formation in chemical ionisation (methane or isobutane) of someortho-alkylhetero-substitute…

2000

The behaviour of some ortho-alkylhetero-substituted diphenylcarbinols, including deuterium labelled derivatives, under chemical ionisation (methane or isobutane) conditions has been investigated. It has been determined that ortho-alkylhetero diphenylmethyl cations formed by water elimination from the protonated molecule undergo consecutive rearrangements which afford benzyl (or tropylium) ions previously observed for ortho-substituted diphenylcarbenium ions generated by electron ionisation. This reaction also occurs under low-energy collision conditions. Copyright © 2000 John Wiley & Sons, Ltd.

Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst

2020

Rhodanine-based dyes absorbing in the entire visible spectrum

2017

A series of new broad-absorbing dyes based on rhodanine derivatives conjugated with triarylamines using Q5 a fluorene backbone was synthesized. Spectroscopic and electrochemical characterizations, along with theoretical calculations at the B3LYP/cc-pVDZ level, revealed interesting properties of the dyes, which make the dyes efficiently absorb in the entire visible spectrum.

Fluorinated heterocyclic compounds. A photochemical synthesis of 3-amino-5-perfluoroaryl-1,2,4-oxadiazoles

2001

Abstract A photochemical methodology for the synthesis of 3-amino- (or 3- N -substituted amino) 5-pentafluorophenyl-1,2,4-oxadiazoles is reported. Irradiation of 3-pentafluorobenzoylamino-4-methyl-1,2,5-oxadiazole (Furazan) at 254 nm in methanol and in the presence of ammonia, primary or secondary aliphatic amines produces 3-amino-, 3-( N -alkylamino)-, 3-( N , N -dialkylamino)-5-pentafluorophenyl-1,2,4-oxadiazoles. The photoreaction follows the fragmentation pattern of the furazan ring with the extrusion of acetonitrile and the formation of a counterpart fragment which the nitrogen nucleophile will capture. Depending on the nature of the reagent, displacement of a fluoride anion at the C(5…

Initial Radical Cation Pathway in the Mo2Cl10-Mediated Dehydrogenative Arene Coupling

2015

Experimental (EPR) and theoretical (DFT) evidence is provided for radical cation formation as initial step in the Mo2Cl10-mediated dehydrogenative arene coupling. The initial electron transfer from methoxyarenes to molybdenum proceeds via an inner sphere mechanism.

Impact of the synergistic collaboration of oligothiophene bridges and ruthenium complexes on the optical properties of dumbbell-shaped compounds.

2012

The linear and non-linear optical properties of a family of dumbbell-shaped dinuclear complexes, in which an oligothiophene chain with various numbers of rings (1, 3, and 6) acts as a bridge between two homoleptic tris(2,2'-bipyridine)ruthenium(II) complexes, have been fully investigated by using a range of spectroscopic techniques (absorption and luminescence, transient absorption, Raman, and non-linear absorption), together with density functional theory calculations. Our results shed light on the impact of the synergistic collaboration between the electronic structures of the two chemical moieties on the optical properties of these materials. Experiments on the linear optical properties …

1984

Light-emitting electrochemical cells based on a supramolecularly-caged phenanthroline-based iridium complex.

2011

The complex [Ir(ppy)(2)(pphen)][PF(6)] (Hppy = 2-phenylpyridine, pphen = 2-phenyl-1,10-phenanthroline) has been prepared and evaluated as an electroluminescent component for light-emitting electrochemical cells (LECs). Like in analogous LECs using bpy-based iridium(III) complexes a significant enhancement of the device stability is observed.

Photocatalytic and Catalytic Reactions in Gas–Solid and in Liquid–Solid Systems

2019

Abstract Heterogeneous photocatalytic and thermal-catalytic reactions are here presented focusing the differences and similarities between the two processes. When possible, the comparison was made for the same chemical reaction in the presence of an inorganic material playing the role of both catalyst or/and photocatalyst. Several examples are presented where a catalytic reaction can occur at milder experimental conditions and, particularly, at lower temperature when the system is also irradiated by UV and/or visible light. The differences in mechanistic aspects, conversions, and selectivities between catalytic and photocatalytic reactions will be also considered because these occurrences a…

ChemInform Abstract: Heteropolyacid-Based Materials as Heterogeneous Photocatalysts

2014

Invited for the cover of this issue is the group of Giuseppe Marci and Leonardo Palmisano at the Universita degli Studi di Palermo, Italy. The cover image shows one aspect of the photocatalytic use of heteropolyacids: dye bleaching by irradiation with sunlight.