Studies on Nitroso Compounds. II. Dimerization of 4-Substituted 2,6-Dichloronitrosobenzenes. An Equilibrium Controlled by the Resonance Effect of para Substituents<sup>1</sup>

Holmes, Richard R.; Bayer, Raymond P.; Errede, L. A.; Davis, Horace R.; Wiesenfeld, Arnold W.; Bergman, Paul M.; Nicholas, David L.

doi:10.1021/jo01022a056

Cited by 19 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…UV–vis spectroscopy has been widely used to measure equilibrium constants for nitrosoareness and their dimers, but relatively little work has been carried out at variable temperatures to allow thermodynamic parameters to be extracted. − In addition, a major shortcoming of UV–vis spectroscopy is that it does not allow equilibrium-related parameters for cis - and trans -azodioxides to be measured individually. The advent of advanced NMR spectroscopy eventually permitted these data to be determined in solution.…”

Section: Monomer–dimer Equilibria In Solutionmentioning

confidence: 99%

Dimerization of Aromatic C-Nitroso Compounds

2016

View full text Add to dashboard Cite

Aromatic C-nitroso compounds (Ar-N═O) and related species have a rich chemical history, and they continue to interest researchers in many fields. Among the most distinctive and puzzling properties of these compounds is their ability to dimerize reversibly to form azodioxy compounds. The present review subjects this intriguing phenomenon to comprehensive analysis. All aspects of the subject are examined in detail, including the structures of monomeric and dimeric forms, the mechanism of dimerization, features that favor or disfavor dimerization, thermodynamic and kinetic factors, dimerization under specific conditions (including in solution, in the solid state, and on surfaces), and the special associative behavior of dinitroso and polynitroso compounds. By summarizing the current state of knowledge, the review promises to spur further advances in the evergreen field of C-nitroso chemistry, including the discovery of new ways to exploit the reversible dimerization of nitrosoarenes.

show abstract

Section: Monomer–dimer Equilibria In Solutionmentioning

confidence: 99%

Dimerization of Aromatic C-Nitroso Compounds

2016

View full text Add to dashboard Cite

show abstract

“…Ϫ100 ЊC. On the other hand, both 2,6-dimethyl-4-methoxynitrosobenzene 9 and 2,6-dichloro-4-methoxynitrosobenzene 10,11 are dimeric in the solid state but dimer-monomer equilibria are established in benzene solution 10 at 25 ЊC. It is apparent that in these cases the combined steric effect of the 2-and 6-substituents is of very similar magnitude to the charge-transfer effect.…”

mentioning

confidence: 97%

Nitrosoanisoles. Sensitive indicators of dimerisation criteria for C-nitrosoarenes

2001

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

“…Ces resultats s'accordent parfaitement avec ceux obtenus en solution. Divers facteurs suggkrent qu l'interaction .rr conjuguee entre le groupe nitroso et le cycle imidazole joue un r61e relativement peu important.[Traduit par la revue]Extensive studies of the 2-nitroimidazole radiosensitizers as has been characterized for nitrosobenzenes (14)(15)(16)(17). This have revealed a number of biological and biochemical effects paper presents our examination of this phenomenon, at both the that are associated with reductive metabolism (1-6).…”

unclassified

“…Extensive studies of the 2-nitroimidazole radiosensitizers as has been characterized for nitrosobenzenes (14)(15)(16)(17). This have revealed a number of biological and biochemical effects paper presents our examination of this phenomenon, at both the that are associated with reductive metabolism (1-6).…”

mentioning

confidence: 99%

Experimental and theoretical investigation of C-nitroso rotation in 2-nitrosoimidazoles

1988

View full text Add to dashboard Cite

Can. J . Chem. 66, 3044 (1988). I-Methyl-2-nitrosoimidazole exhibits broadened 'H nuclear magnetic resonance signals at room temperature. The concentration independency of this spectrum as well as the linearity of the 700-nm absorbance with concentration rules out equilibrating nitroso monomer -nitroso dimer. It is suggested that there are equilibrating s-cis and s-trans nitroso monomer rotational isomers. At -59°C two sets of signals in a 3:l ratio are observed. Analysis of CH3 chemical shifts in terms of the magnetic anisotropy of the nitroso group suggests that the s-trans is the major isomer. The broadening observed at higher temperatures leads to a barrier for rotation (from the trans isomer) of 12.4 kcal mol-'. Ab initio calculations with 2-nitrosoimidazole using the 3-21G basis set show that the fully planar s-cis and s-trans forms are minima, with the s-trans more stable by 2.5 kcal mol-', and a barrier to rotation (from the s-trans) of 13.0 kcal mol-'. These results are in good agreement with those from solution phase. Various factors suggest that the .rr conjugative interaction between the nitroso group and imidazole ring is relatively unimportant. JUDY L. BOLTON, MICHAEL R. PETERSON et ROBERT A. MCCLELLAND. Can. J. Chem. 66, 3044 (1988). Le mtthyl-1 nitroso-2 imidazole prtsente en tnlargissement des signaux de rtsonance magnetique nucleaire du 'H a la temperature ambiante. L'absence de relation entre le spectre et la concentration aussi bien que la relation de proportionnalite existant entre la concentration et I'absorption ii 700 nm tcartent la posibilite d'un Cquilibre monomere nitroso -dimere nitroso.On suggkre qu'il y a un tquilibre entre les isomkres rotationnels s-ciset s-trans du monomkre nitroso. On observe a -59°C deux groupes de signaux dans un rapport 3:l. L'analyse des dCplacements chimiques en fonction de l'anisotropie magnktique du groupe nitroso suggkre que l'isomkre s-trans est majoritaire. L'Clargissement des signaux observe plus haute temptrature conduit a une barrikre 2 la rotation de 12.4 kcal mol-' (pour l'isomkre bans). Les calculs ab initio effectues avec le nitroso-2 imidazole en utilisant l'ensemble de base 3-2 IG montrent que les formes totalement planes s-cis et s-trans sont minimales. La forme S-bans est plus stable de 2.5 kcal mol-' avec une barribre a la rotation de 13.0 kcal mol-'. Ces resultats s'accordent parfaitement avec ceux obtenus en solution. Divers facteurs suggkrent qu l'interaction .rr conjuguee entre le groupe nitroso et le cycle imidazole joue un r61e relativement peu important.[Traduit par la revue]Extensive studies of the 2-nitroimidazole radiosensitizers as has been characterized for nitrosobenzenes (14)(15)(16)(17). This have revealed a number of biological and biochemical effects paper presents our examination of this phenomenon, at both the that are associated with reductive metabolism (1-6). The experimental and theoretical level. As will be shown, our initial implication is that biological reduction is producing some premise was incorrect. The nrnr ...

show abstract

Studies on Nitroso Compounds. II. Dimerization of 4-Substituted 2,6-Dichloronitrosobenzenes. An Equilibrium Controlled by the Resonance Effect of para Substituents¹

Cited by 19 publications

References 0 publications

Dimerization of Aromatic C-Nitroso Compounds

Dimerization of Aromatic C-Nitroso Compounds

Nitrosoanisoles. Sensitive indicators of dimerisation criteria for C-nitrosoarenes

Experimental and theoretical investigation of C-nitroso rotation in 2-nitrosoimidazoles

Contact Info

Product

Resources

About

Studies on Nitroso Compounds. II. Dimerization of 4-Substituted 2,6-Dichloronitrosobenzenes. An Equilibrium Controlled by the Resonance Effect of para Substituents1

Cited by 19 publications

References 0 publications

Dimerization of Aromatic C-Nitroso Compounds

Dimerization of Aromatic C-Nitroso Compounds

Nitrosoanisoles. Sensitive indicators of dimerisation criteria for C-nitrosoarenes

Experimental and theoretical investigation of C-nitroso rotation in 2-nitrosoimidazoles

Contact Info

Product

Resources

About

Studies on Nitroso Compounds. II. Dimerization of 4-Substituted 2,6-Dichloronitrosobenzenes. An Equilibrium Controlled by the Resonance Effect of para Substituents¹