Photoinduced Cleavage of the C-C Bond of 9-(1-Naphthylmethyl)-10-methyl-9,10-dihydroacridine by Perchloric Acid via Intramolecular Electron-Transfer Excitation

Article abstract of DOI:10.1021/j100200a038

The C(9)-C bond of 9-(1-naphthylmethyl)-10-methyl-9,10-dihydroacridine (AcrHR) is readily cleaved by HClO4 in acetonitrile (MeCN) under irradiation of the absorption band of AcrHR to yield RH and AcrH⁺.The dependence of the fluorescence maximum on solvent dielectric constant indicates a highly polar singlet excited state with the dipole moment of ca. 15.6 D, while the fluorescence maximum of 9,10-dihydro-10-methylacridine (AcrH2) is insensitive to the solvent.The fluorescence of AcrHR is efficiently quenched by HClO4 with the rate constant of 8.6 * 10⁹ M^-1 s^-1 in MeCN at 298 K.The same quenching rate constant has been obtained from the dependence of the quantum yields on for the photoinduced cleavage of the C-C bond of AcrHR by HClO4 in MeCN at 298 K.Thus, the photoinduced intramolecular charge transfer from the acridine moiety to the naphthalene moiety in AcrHR results in the generation of the highly polarized C-C bond which is susceptible to the cleavage by HClO4.The C(9)-C bond of AcrHR is also cleaved upon the intermolecular electron-transferoxidation of AcrHR by Fe(ClO4)3 and Fe(phen)3 and Fe(phen)3³⁺ (phen = 1,10-phenanthroline) in MeCN to yield AcrH⁺, while the C(9)-H bond is cleaved in the case of AcrH2.