First Observation of Monomer and Dimer Radical Cation upon Photoreduction of Cyanopyridinium Derivatives in Solution by Electron Spin Resonance and Absorption Spectroscopy
作者:Sang Hyun Park、Hideki Kawai、Toshihiko Nagamura
DOI:10.1021/jp025786x
日期:2002.12.1
The monomer radical and the dimer radicalcation of cyanopyridinium derivatives have been studied by absorption and electronspinresonance (ESR) spectroscopies at room temperature in acetonitrile ...
Ionic liquid characteristics of 1-alkyl-n-cyanopyridinium and 1-alkyl-n-(trifluoromethyl)pyridinium salts
作者:Christopher Hardacre、John D. Holbrey、Claire L. Mullan、Mark Nieuwenhuyzen、W. Matthew Reichert、Kenneth R. Seddon、Simon J. Teat
DOI:10.1039/b805063e
日期:——
1-Alkyl-n-cyanopyridinium and 1-alkyl-n-(trifluoromethyl)pyridinium salts have been synthesised and characterised in order to compare the effects of different electron-withdrawing functional groups on their ability to form ionic liquids. The presence of the electron-withdrawing nitrile or trifluoromethyl substituent on the pyridinium ring leads to salts with higher melting points than with the corresponding 1-alkylpyridinium or 1-alkylpicolinium cations. Solid-state structures were determined by single crystal X-ray crystallography for seven salts; 1-methyl-4-cyanopyridinium methylsulfate, and 1-methyl-3-cyanopyridinium, 1-methyl-4-cyanopyridinium, 1-ethyl-2-cyanopyridinium, 1-ethyl-3-cyanopyridinium, 1-ethyl-4-cyanopyridinium and 1-ethyl-4-(trifluormethyl)pyridinium bis(trifluoromethyl)sulfonyl}imide, and show the effects of ring-substitution position on hydrogen-bonding in the solid-state and on melting points.
Kinetic demonstration of premicellar aggregation. The alkaline hydrolysis of N-hexadecyl-4-cyanopyridinium bromide
作者:N. Hioka、M.J. Politi、H. Chaimovich
DOI:10.1016/s0040-4039(01)80356-7
日期:1989.1
The critical micelle concentration (CMC) of N-hexadecyl-4-cyanopyridinium (HCP) bromide, determined by conductivity or fluorescence quenching, was 7–8 ∗ 10-4 M. The observed rate constants for the hydrolysis of HCP below the CMC increased with the concentration of this amphiphile from 2 ∗ 10-6 M up to the CMC. The product ratio (pyridone/amide) also varied with HCP concentration. The analysis of both