The identification of distonic radical cations on the basis of a reaction with dimethyl disulfide

1992 ◽  
Vol 114 (22) ◽  
pp. 8604-8606 ◽  
Author(s):  
Krista M. Stirk ◽  
Joseph C. Orlowski ◽  
Diane T. Leeck ◽  
H. I. Kenttamaa
Keyword(s):  
Dimethyl Disulfide ◽  
Radical Cations

Unusual Reactivity of the Radical Cations of Some Simple Trivalent Organophosphorus Compounds toward Dimethyl Disulfide and Dimethyl Diselenide

1996 ◽  
Vol 118 (6) ◽  
pp. 1408-1412 ◽  
Author(s):  
Rebecca L. Smith ◽  
Andreas Schweighofer ◽  
Helmut Keck ◽  
Wilhelm Kuchen ◽  
Hilkka I. Kenttämaa
Keyword(s):  
Organophosphorus Compounds ◽  
Dimethyl Disulfide ◽  
Radical Cations ◽  
Dimethyl Diselenide

ChemInform Abstract: The Identification of Distonic Radical Cations on the Basis of a Reaction with Dimethyl Disulfide

ChemInform ◽  
2010 ◽  
Vol 24 (7) ◽  
pp. no-no
Author(s):  
K. M. STIRK ◽  
J. C. ORLOWSKI ◽  
D. T. LEECK ◽  
H. I. KENTTAEMAA
Keyword(s):  
Dimethyl Disulfide ◽  
Radical Cations

Reactivity Trends in the Gas Phase Addition of Acetylene to N-protonated Aryl Radical Cations

2020 ◽  
Author(s):  
Oisin Shiels ◽  
P. D. Kelly ◽  
Cameron C. Bright ◽  
Berwyck L. J. Poad ◽  
Stephen Blanksby ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ion Trap ◽  
Radical Cations ◽  
Rate Coefficients ◽  
Similar Process ◽  
Ion Molecule Reactions ◽  
Aromatic Radicals ◽  
Polycyclic Aromatic ◽  
Gas Phase Ion ◽  
Type Radical

<div> <div> <div> <p>A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N- containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl) and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios and reaction efficiencies are reported. </p> </div> </div> </div>

Characterization of odorous compounds from bleached kraft pulp mill effluent

1995 ◽  
Vol 31 (11) ◽  
pp. 35-40 ◽  
Author(s):  
B. G. Brownlee ◽  
S. L. Kenefick ◽  
G. A. MacInnis ◽  
S. E. Hrudey
Keyword(s):  
Gas Chromatography ◽  
Kraft Pulp ◽  
Pulp Mill ◽  
Dimethyl Disulfide ◽  
Gas Chromatography Mass Spectrometry ◽  
Pulp Mill Effluent ◽  
Kraft Pulp Mill ◽  
Bleached Kraft Pulp ◽  
Methyl Phenyl Sulfide ◽  
Library Spectrum

Odour compounds in extracts of bleached kraft pulp mill effluent (BKME) have been characterized by olfactory gas chromatography (OGC) and gas chromatography-mass spectrometry. A variety of sulfury odours was detected by OGC in addition to woody and pulp mill-like odours. Three sulfur compounds were identified by comparison of retention times and partial mass spectra with authentic standards: dimethyl disulfide, 3-methylthiophene and thioanisole (methyl phenyl sulfide). Typical concentrations in BKME were 1, 0.05, and 0.5 μg/l, respectively. Their odour intensity is relatively low and they were not detected by OGC. Dimethyl trisulfide was tentatively identified by comparison of its partial mass spectrum with a literature (library) spectrum. Its concentration in BKME was estimated at 0.5-2 μg/l. It corresponded to a skunky odour in the OGC profiles. Efforts to identify another odour peak, eluting just after 3-methylthiophene, with a pronounced alkyl sulfide odour were unsuccessful.

Properties and Reactivity of First and Second Row Hydrides. IV. Interactions Between Hydrides and Their Radical Ions

1993 ◽  
Vol 58 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Rudolf Zahradník
Keyword(s):  
Radical Cations ◽  
Stabilization Energy ◽  
Hydrogen Atom Abstraction ◽  
Type Ii ◽  
Radical Ions ◽  
Reaction Products ◽  
Ion Molecule Reactions ◽  
Heats Of Reaction ◽  
Experimental Values ◽  
Easy Differentiation

The energies and heats of ion-molecule reactions have been calculated (MP4/6-31G**//6-31G** or better level) and compared with the experimental values obtained from the heats of formation. Two main types of reactions have been studied: (i) AHn + AHn+• ↔ AHn+1+ + AHn-1• (A = C to F and Si to Cl), (ii) AHn + BHm+• ↔ AHn+1+ + BHm-1• or AHn-1+• + BHm+1+ (A and B = C to F). In contrast to (i), processes of type (ii) permit easy differentiation between the proton transfer and hydrogen atom abstraction mechanisms. A third type of interaction involves reactions with radical anions (A = Li to F); comparison was made with analogous processes with radical cations. A brief comment is made about the influence of the level of computational sophistication on the energies and heats of reaction, as well as on the stabilization energy of a hydrogen bonded intermediate, a structure which is similar to that of the reaction products.

Electrostatic effects on ionization equilibria: An MNDO study of proton and hydrogen transfer reactions of 4-fluorobutylamine

1990 ◽  
Vol 55 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Zdeněk Friedl ◽  
Stanislav Böhm
Keyword(s):  
Hydrogen Transfer ◽  
Substituent Effects ◽  
Radical Cations ◽  
Transfer Reactions ◽  
Protonated Forms ◽  
Minor Part ◽  
Bond Strengths ◽  
Ionization Equilibria ◽  
A Minor ◽  
Gas Phase Basicities

The relative enthalpies of proton transfer δ ΔH0and homolytic bond strengths δDH0(B-H+) were calculated by the MNDO method for the sp and ap conformers of 4-flurobutylamine. The data obtained, along with the experimental gas phase basicities, are compared with the values predicted by the electrostatic theory. It is shown that the substituent polar effects FD on the basicities of amines are predominantly due to interactions in their protonated forms (X-B-H+) and/or radical-cations (X-B+.), those in the neutral species (X-B) playing a minor part. A contribution, which is considerably more significant in the sp conformer than in the ap conformer, arises probably also from substituent effects on the homolytic bond strength DH0(B-H+.

A Combined ab initio and Density Functional Study of the Electronic Structure of Thymine and 2-Thiothymine Radicals

2003 ◽  
Vol 68 (12) ◽  
pp. 2322-2334 ◽  
Author(s):  
Robert Vianello ◽  
Zvonimir B. Maksić
Keyword(s):  
Ab Initio ◽  
Spin Density ◽  
Density Functional ◽  
Radical Cations ◽  
Functional Study ◽  
Theory Approach ◽  
Functional Theory ◽  
Adiabatic Ionization Potential ◽  
Highest Occupied Molecular Orbital ◽  
Positively Charged

The electronic and energetic properties of thymine (1) and 2-thiothymine (2) and their neutral and positively charged radicals are considered by a combined ab initio and density functional theory approach. It is conclusively shown that ionization of 1 and 2 greatly facilitates deprotonation of the formed radical cations thus making the proton transfer between charged and neutral precursor species thermodynamically favourable. The adiabatic ionization potential of 1 and 2 are analysed. It appears that ADIP(1) is larger than ADIP(2) by 10 kcal/mol, because of greater stability of the highest occupied molecular orbital (HOMO) of the former. It is also shown beyond any doubt that the spin density in neutral and cationic radical of 2 is almost exclusively placed on the σ-3p AO of sulfur implying that these two systems represent rather rare sigma-radicals. In contrast, the spin density of radicals of 1 is distributed over their π-network.

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