Electron spin resonance organic radical ions

Ionic processes of monomers, nitroethylene, n-butylvinylether and styrene, in organic glass matrices of 2-methyltetrahydrofuran, 3-methyl-pentane and n-butylchloride irradiated by y-rays at 77° K, are studied by observing the electron spin resonance spectra of trapped electrons and ion radicals formed from the solute monomers. The primary ionic intermediates are the trapped electrons and their counterpart, cation radicals of matrix molecules. However, in 2-methyltetrahydrofuran glass, the anionic processes of solute monomers resulting from the trapped electrons proceed selectively. On the contrary, only the cationic processes proceed selectively in n-butylchloride glass. Both processes are able to occur in 3-methylpentane glass. 

From a synthetic objective it is unfortunate that attempts to produce the dianion of OFCOT by various reduction procedures have not resulted in a stable dianion. Although the organic decomposition products resulting from reduction by alkali metals or sodium naphthalenide are unknown, fluoride ion is produced (126). However, the nine-7t-electron radical anion has been produced at low temperatures by y irradiation of OFCOT, and electron spin resonance (ESR) spectroscopy indicates that it possesses the anticipated planar delocalized D8b structure 55 (127). The unavailability of the dianion... 

Electron spin resonance (ESR) spectroscopy is of application to organic species containing unpaired electrons radicals, radical ions and triplet states, and is much more sensitive than NMR it is an extremely powerful tool in the field of radical chemistry (see Chapter 10). Highly unstable radicals can be generated in situ or, if necessary, trapped into solid matrices at very low temperatures. Examples of the application of this techniques include study of the formation of radical cations of methoxylated benzenes by reaction with different strong oxidants in aqueous solution [45], and the study of the photodissociation of N-trityl-anilines [46],... 

Since the primary intermediates in organic electrode reactions are usually radical ions or neutral radicals, the combination of electrochemical equipment with an electron spin resonance (ESR) spectrometer is a desirable possibility. The major practical problem encountered in designing an adequate experimental setup arises from the physical restrictions imposed on the electrochemical cell by the shape and size of the resonance cavity. Two different approaches have been taken to meet the requirements. One involves the formation of the radical species outside the magnetic field in a streaming solution that carries the electrode products into the ESR cavity. By the other technique the radical species are formed by electrolysis in a small cell placed directly in the cavity. Both techniques have for many years been used extensively in qualitative and semiquantitative work, and the design and construction of cells have now reached a high level of sophistication [363-377]. 

Electron-spin resonance (e.s.r.) spectroscopy is a technique for the study of species containing one or more unpaired electrons. The scope of the method includes the detection and characterization of some transition-metal ions, simple molecules and ions (e.g. O2, NO, NOg, COi"), and organic radicals, including biradicals and triplet states. 

Characterization of Phenalenyl Radicals in Various Fuel Samples. Fuel, Vol. 69, No. 2, (February 1990), pp. 203-206, ISSN 0016-2361 Sogo, P. B., Nakazaki, M Calvin, M. (1957). Free Radical from Peiinaphthene. Journal of Chemical Physics, Vol. 26, No. 5, (May, 1957) pp. 1343-1345, ISSN 0021-9606 Uesugi, A. Ikeya, M. (2001). Electron Spin Resonance Measurement of Organic Radicals in Petroleum Source Rock Containing Transition Metal Ions. Japanese Journal of Applied Physics Part 1-Regular Papers Short Notes Reoiew Papers. Vol. 40, No. 4A, (April 2001), p. 2251-2254, ISSN 0021 922... 

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