Cyclopropyl 3 hyperfine splittings

FIGURE 26 (a) MP2/6-31G(d) geometry of the cyclopropyl radical 40 according to Reference 246. (b) Spin-coupling scheme of the cyclopropyl radical according to the intra-atomic Hund rule and spin coupling within bonds. Hyperfine splitting aN at nucleus N will be > 0 ( < 0) if valence electrons at N possess oc (/ ) spin... 

TABLE 28. Isotropic hyperfine splittings (Gauss) of the cyclopropyl radical computed at the UMP2/DZ + P level250... 

Cuprous cyclopropylacetylide, prepared from Cul and cyclopropylacetylene in ammo niacal solution couples with 4-iodonitrobenzene in pyridine, yielding 4-nitrophenyl cyclopropylacetylene (equation 154)234. Reaction of the acetylide with tropylium tetra-fluoroborate in acetonitrile, in the presence of LiBr, affords 7-(cyclopropylethynyl)cyclo-heptatriene. The anion radicals obtained by reduction of these compounds were utilized for ESR spectroscopic analysis of the cyclopropyl P hyperfine splittings. 

Table I H and C Hyperfine Splittings (Gauss G) for Cyclopropyl and 1-Methyl-cyclopropyl Radical in Cyclopropane at -70 C...

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