Spin trapping by nitrosoalkanes: Mechanisms of Some Photochemically Induced Reactions - Brossura

Hartgerink, Jan Willem

 
9789401186506: Spin trapping by nitrosoalkanes: Mechanisms of Some Photochemically Induced Reactions

Sinossi

This thesis is based on the excellent radical scavenging properties of mono­ meric nitrosoalkanes RNO. Thus, addition of a small amount of RNO to a reacting system in which unstable radicals X· are generated usually results in the formation of relatively stable nitroxides, which can be studied by ESR spectroscopy at room temperature . . R-N=O + X --R-N-X ,. o The nature of the trapped radical X· can very often be deduced from the hyperfine splittings (hfs) and g-value of the ESR spectrum of the derived nitroxide. Thus the ESR Spin Trapping technique is useful for the identifi­ cation of highly reactive (short-living) radicals X·. Chapter 1 contains a survey of the literature and a short description of the most important features of nitrosoalkanes, nitroxides and the Spin Trapping technique in general. In chapter 2 the synthesis of hitherto unknown I-nitrosoadamantane is described. Together with a number of other nitrosoalkanes it is used as a scavenger for trifluoromethyl radicals, generated by photolysis of trifluoro­ iodomethane. The derived alkyl trifluoromethyl nitroxides with aN = aF = 11.5-12.0 gauss are easily identified and are found to be very stable at room temperature. Chapter 3 illustrates the limitations of the Spin Trapping technique, i.e.

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Contenuti

1. Introduction and Survey of Literature.- Nitrosoalkanes.- Nitroxides.- ESR Spin Trapping techniques.- 2. Trapping of Trifluoromethyl Radicals by Monomeric Nitrosoalkanes. Synthesis of 1-Nitrosoadamantane.- Results and discussion.- Experimental.- 3. Photolysis of Polyhalomethanes in the Presence of Nitrosoalkanes. Formation of Acyl Alkyl Nitroxides.- Results and discussion.- Experimental.- 4. Photochemically Initiated Reactions of Substituted 1, 3-Dioxolanes and 1, 3-Oxathiolanes in CFCL3. Esr Study and Mechanism of Ring-Fission.- Results and discussion.- Experimental.- Summary.- Samenvatting.

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