Knowledge Bank

The paramagnetic resonance spectra of three isotopically substituted naphthalene negative ions have been studied under moderate resolution to determine the $\alpha -$ and $\beta -$ proton, and $\alpha -C13$ hyperfine splitting factors. The spectrum of the $\beta -$ deutero compound has 15 peaks and that of the $\beta$-deutero 14 peaks. These facts, along with the relative intensities of lines, lead to values of the proton splitting on the $\beta -$ position of \underline{5.1} gauss and on the $\beta -$ position of \underline{1.7} gauss. Naphthalene negative ion with 53 atom percent $C13$ in the $\alpha -$ position gives a spectrum of 21 lines. An assignment of 5.4 gauss for the $\alpha -C13$ splitting gives good agreement with the observed spectrum. The observed splittings will be compared with those calculated using S. I. Weissman’s method involving configurational $interaction1$.