Roths

Roth et aJ [10] have used CIDNP to study the structures of vinylcyclopropane radical cations fomied from precursors such as sabinene (1). 

The radical cation of 1 (T ) is produced by a photo-induced electron transfer reaction with an excited electron acceptor, chloranil. The major product observed in the CIDNP spectrum is the regenerated electron donor, 1. The parameters for Kaptein s net effect rule in this case are that the RP is from a triplet precursor (p. is +), the recombination product is that which is under consideration (e is +) and Ag is negative. This leaves the sign of the hyperfine coupling constant as the only unknown in the expression for the polarization phase. Roth et aJ [10] used the phase and intensity of each signal to detemiine the relative signs and magnitudes of the... 

The CIDNP spectrum is shown in figure B 1.16.1 from the introduction, top trace, while a dark spectrum is shown for comparison in figure B 1.16.1 bottom trace. Because the sign and magnitude of the hyperfine coupling constant can be a measure of the spin density on a carbon, Roth et aJ [10] were able to use the... 

Roth H D, Weng H and Herbertz T 1997 CIDNP study and ab initio calculations of rigid vinylcyclopropane systems evidence for delocalized ring-closed radical cations Tetrahedron 53 10 051-70... 

Kresge C T, Leonowicz M E, Roth W J, Vartuli J C and Beck J S 1992 Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism Nature 359 710-12... 

Vartuli J C, Roth W J, Beck J S, McCullen S B and Kresge C T 1998 The synthesis and properties of M41S and related mesoporous materials Moiecuiar Sieves Science and Technoiogy vol 1, ed FI G Karge and J Weitkamp (Berlin Springer) pp 97-119... 

D. Forster and J. F. Roth, eds.. Homogeneous Catalysis 11 (Advances ia Chemistry Series 132), American Chemical Society, Washiagton, D.C. 1974 ... 

Functional Group Analysis. The total hydroxyl content of lignin is determined by acetylation with an acetic anhydride—pyridine reagent followed by saponification of the acetate, and followed by titration of the resulting acetic acid with a standard 0.05 W sodium hydroxide solution. Either the Kuhn-Roth (35) or the modified Bethge-Liadstrom (36) procedure may be used to determine the total hydroxyl content. The aUphatic hydroxyl content is determined by the difference between the total and phenoHc hydroxyl contents. 

R. M. Garrels, F. T. Mackenzie, and C. Hunt, Chemical Cycles and the Global Environment Assessing Human Influences, Kaufman, Inc., Los Altos, Calif, 1975 A. J. M. Schoot Uiterkamp, in P. M. Gresshoff, L. E. Roth, G. Stacey, and W. E. Newton, eds.. Nitrogen Eixation Achievements and Objectives, Chapman and Hall, London, 1990, p. 55. 

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