Search results for "Radical ion"
showing 7 items of 57 documents
Crystal structure of bis(ethylenedithio)tetrathiafulvalenium μ2-acetato-bis[tribromidorhenate(III)] 1,1,2-trichloroethane hemisolvate
2016
The crystal structure of a binuclear monocarboxylato dirhenium(III) complex with a fulvalene derivative is reported. This compound represents a radical cation salt containing a cluster unit with rhenium–rhenium quadruple bond.
ESR study of thianthrenium radical cation within acid zeolites
1997
Abstract Thianthrene (E ox = 1.47 V vs NHE) has been adsorbed into a series of zeolites beta (s) and ZSM-5 in the NH 4 + or H + forms, having different particle size and Si/Al ratio. The resulting population of generated thianthrenium radical cation was determined by a combination of diffuse reflectance and ESR spectroscopies. From the results obtained it can be concluded: i) the process takes predominantly place in the interior of the voids (XPS measurements and lack of influence of the particle size); ii) ZSM-5 is more efficient than zeolite s; iii) no strong acid sites are required (both NH 4 + and H + forms produced very similar spin concentrations); iv) the zeolite framework acts isola…
Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study
2009
Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features d…
Self-Assembled Molecular Rafts at Liquid|Liquid Interfaces for Four-Electron Oxygen Reduction
2011
The self-assembly of the oppositely charged water-soluble porphyrins, cobalt tetramethylpyridinium porphyrin (CoTMPyP(4+)) and cobalt tetrasulphonatophenyl porphyrin (CoTPPS(4-)), at the interface with an organic solvent to form molecular "rafts", provides an excellent catalyst to perform the interfacial four-electron reduction of oxygen by lipophilic electron donors such as tetrathiafulvalene (TTF). The catalytic activity and selectivity of the self-assembled catalyst toward the four-electron pathway was found to be as good as that of the Pacman type cofacial cobalt porphyrins. The assembly has been characterized by UV-visible spectroscopy, Surface Second Harmonic Generation, and Scanning …
Room-Temperature Magnetic Bistability in a Salt of Organic Radical Ions
2021
International audience; Cocrystallization of 7,7′,8,8′-tetracyanoquinodimethane radical anion (TCNQ −•) and 3-methylpyridinium-1,2,3,5dithiadiazolyl radical cation (3-MepyDTDA +•) afforded isostructural acetonitrile (MeCN) or propionitrile (EtCN) solvates containing cofacial π dimers of homologous components. Loss of lattice solvent from the diamagnetic solvates above 366 K affords a high-temperature paramagnetic phase containing discrete TCNQ −• and weakly bound π dimers of 3-MepyDTDA +• , as evidenced by X-ray diffraction methods and magnetic susceptibility measurements. Below 268 K, a first-order phase transition occurs, leading to a low-temperature diamagnetic phase with TCNQ −• σ dimer…
New charge transfer salts of two organic π-donors of the tetrathiafulvalene type with the paramagnetic [Cr(NCS)6]3- anion
2003
cited By 9; International audience; The electrochemical combination of the paramagnetic anion [Cr(NCS)6]3- with the organic π-donors bis(ethylenedithio)tetrathiafulvalene (ET) and 4,5-bis(2-hydroxyethylthio) -4′,5′-ethylenedithiotetrathiafulvalene (DHET-EDTTTF) leads to two new radical cation salts, namely (ET)4 [Cr(NCS 6]·PhCN 1 and (DHET-EDTTTF)2 (NEt4)[Cr(NCS)6] 2. Both have been characterized by X-ray crystallography, magnetic and resistivity measurements. The structure of 1 consists of alternating inorganic layers generated by the anions and organic layers in which the PhCN molecules are inserted; the organic sub-lattice is built up from four different ET units, three of them with a ch…
Studies in organic mass spectrometry. Part 23. Role of the aroyl group on the competitive fragmentation reactions of the molecular ion of aroylanilid…
1999
The 70 eV and mass-analysed ion kinetic energy (MIKE) spectra of some thiophenecarboxanilides and benzoylanilides (1–10) have been compared in order to investigate the role of the aroyl (or heteroaroyl) moiety on the abundance of the competitive fragmentation reactions occurring in their molecular ions (amide–bond cleavage and phenol radical ion formation). It has been shown that the electron ionisation induced decompositions with high (70 eV) and low (MIKE) internal energy excess are qualitatively similar, but remarkable quantitative differences have been observed that can be accounted for in terms of the different effectiveness in the transmission of electronic effects of substituents in …