The radical cation of naphthalene: First correct analysis of its ESR spectrum

✍ Scribed by Fabian Gerson; Xue-Zhi Qin

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 399 KB
• Volume: 153
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(88)85258-8

✦ Synopsis

The radical cations of naphthalene (1) and its 1,6dideutero derivative (l-d,). generated from the corresponding neutral compounds by y-rays in a CFCI, matrix at 77 K, have been studied by ESR and ENDOR spectroscopy. At 140 K, the hyperfineanisotropy tensors of the protons in I+' appear to be quasi-axial, presumably as a consequence of the fast rotation about the twofold symmetry axis perpendicular to the molecular plane. The isotropic coupling constants are -0.74? 0.0 I and -0. I87 & 0.0 I4 mT for the two sets of four equivalent protons in the 1,4,5,8-and 2,3,6,7-positions, rcspcctively. The relative increase in the coupling constant of the I ,4,5,8-protons on going from the radical anion l-' ( -0.495 mT) to the radical cation I+' ( -0.74 mT) is similar to that found for the 1,4-protons in the corresponding radical ions (Z-' and 2+') ofs-trans-buta-1,3-diene

(2).