The Redox Chemistry of 4-Benzoyl-<i>N-</i>methylpyridinium Cations in Acetonitrile with and without Proton Donors: The Role of Hydrogen Bonding
作者:Nicholas Leventis、Ian A. Elder、Xuerong Gao、Eric W. Bohannan、Chariklia Sotiriou-Leventis、Abdel Monem M. Rawashdeh、Travis J. Overschmidt、Kimberly R. Gaston
DOI:10.1021/jp0107199
日期:2001.5.1
In anhydrous CH3CN, 4-benzoyl-N-methylpyridinium cations undergo two reversible, well-separated (ΔE1/2 ∼ 0.6 V) one-electron reductions in analogy to quinones and viologens. If the solvent contains weak protic acids, such as water or alcohols, the first cyclic voltammetric wave remains unaffected while the second wave is shifted closer to the first. Both voltammetric and spectroelectrochemical evidence
Tuning the Redox Chemistry of 4-Benzoyl-<i>N</i>-methylpyridinium Cations through Para Substitution. Hammett Linear Free Energy Relationships and the Relative Aptitude of the Two-Electron Reduced Forms for H-Bonding
作者:Nicholas Leventis、Abdel-Monem M. Rawaswdeh、Guohui Zhang、Ian A. Elder、Chariklia Sotiriou-Leventis
DOI:10.1021/jo020489+
日期:2002.10.1
catalysts such as quinones and viologens. Hammett linear free energy plots yield excellent correlation between the E(1/2) values of both waves and the substituent constants sigma(p)(-)(X). The reaction constants for the two 1-e reductions are rho(1) = 2.60 and rho(2) = 3.31. The lower rho(1) value is associated with neutralization of the pyridinium ring, and the higher rho(2) value with the negative charge