23686-88-6Relevant academic research and scientific papers
Electron Paramagnetic Resonance of the Interaction of Semiquione, Na(+) Ion Pairs with Phosphatidylcholine in Ethereal Solvents
Alegria, Antonio,Moctezuma, Angel,Velazquez, Betty
, p. 3363 - 3370 (2007/10/02)
The solubilization of sodium slats of 1,4-benzosemiquinone (BQ.-), 1,4-naphthosemiquinone (NQ.-), 2,3,5,6-tetramethylbenzosemiquinone (DQ.-), 2-methyl-1,4-naphthosemiquinone (MNQ.-), 2,6-di-tert-butyl-1,4-benzosemiquinone (DTBQ.-) and 9,10-anthrasemiquinone (AQ.-) in 1,2-dimethoxyethane (DME) and diethyl ether (DEE), in the presence and absence of egg yolk phosphatidylcholine (PC), under very dry conditions, has been studied utilizing electron paramagnetic resonance (EPR) spectroscopy.EPR spectra corresponding to both the ion pair and the 'free' ion species were observed simultaneously for NQ.-, DQ.- and MNQ.- in the presence of small quantities of PC in DME.Weighted-average EPR spectra were observed for DTBQ.- and AQ.- in DME, evidenced by the monotonic variation of their corresponding g values or proton coupling constants as a function of added PC.Binding constants of the sodium semiquinone salts to PC were determined for both DME and DEE solutions.Binding constants of the solvated sodium-semiquinone ion pairs to PC were also determined for DME solutions.The roles of the solvent and PC in solvating the sodium-semiquinone ion pairs are strongly interrelated.Addition of methyl or tert-butyl groups and extension of the ? cloud to both BQ.- and NQ.- structures decreases the solvated sodium-semiquinone binding to PC in DME implying that solubilization occurs preferentially at the charged sites of the PC molecules.
An Electron Spin Resonance Study of the Radicals formed on Ultravilet irradiation of the Photoallergens Fentichlor and Bithionol
Delahanty, Jonathan N.,Evans, Jeffrey C.,Rowlands, Christopher C.,Barratt, Martin D.
, p. 135 - 140 (2007/10/02)
Radicals formed on u.v. irradation of aqueous solutions (pH 8) of fentichlor and bithionol have been detected by e.s.r. spectroscopy.The radicals have been identified as substituted benzosemiquinone radicals and the proton hyperfine coupling constants have been assigned on the basis of methyl substitutions.
