Experimental determination of the alpha and beta C-H bond dissociation energies in naphthalene

The acidities of the two different sites in naphthalene (1 alpha and 1 beta ) and the electron affinities of the alpha- and beta-naphthyl radicals were measured using a Fourier transform mass spectrometer, Both carbon-hydrogen bond dissociation energies for naphthalene also were obtained, in this cas e,ia the application of a thermodynamic cycle. The final results are Delta A(acid)(o) (1 alpha) = 394.2 +/- 1.2 kcal mol(-1), Delta H-acid(o)(1 beta) = 395.5 +/- 1.3 kcal mol(-1), EA(a) = 31.6 +/- 0.5 kcal mol(-1), EA(beta) = 31.6 +/- 0.5 kcal mol(-1), BDE(1 alpha)= 112.2 +/- 1.3 kcal mol(-1) and BD E(1 alpha) = 111.9 +/- 1.3 kcal mol(-1), and they are compared to benzene a nd phenyl radical as well as ab initio and density functional theory (B3LYP ) calculations. Copyright (C) 2000 John Wiley & Sons, Ltd.