title: Electronic Characterization of Reaction Intermediates: The Fluorenylium, Phenalenylium, and Benz[f]indenylium Cations and Their Radicals.
abstract: Three vibrationally resolved absorption systems commencing at 538, 518, and 392 nm were detected in a 6 K neon matrix after mass-selected deposition of C13 H9 (+) ions (m/z=165) produced from fluorene in a hot-cathode discharge ion source. The benz[f]indenylium (BfI(+) : 538 nm), fluorenylium (FL9(+) : 518 nm), and phenalenylium (PHL(+) : 392 nm) cations are the absorbing molecules. Two electronic systems corresponding to neutral species are apparent at 490 and 546 nm after irradiation of the matrix with λ<260 nm photons and were assigned to the FL9 and BfI radicals, respectively. The strongest peak at 518 nm is the origin of the 2 (1) B2 ←X̃ (1) A1 absorption of FL9(+) , and the 490 nm band is the 2 (2) A2 ←X̃ (2) B1 origin of FL9. The electronic systems commencing at 538 nm and 546 nm were assigned to the 1 (1) A1 ←X̃ (1) A1 and 1 (2) A2 ←X̃ (2) A2 transitions of BfI(+) and BfI. The 392 nm band is the 1 (1) E'←X̃ (1) A1 ' transition of PHL(+). The electronic spectra of C13 H9 (+) /C13 H9 were assigned on the basis of the vertical excitation energies calculated with SAC-CI and MS-CASPT2 methods.
authors: Departement Chemie, Universität Basel, Klingelbergstrasse 80, 4056, Basel, Switzerland.|Institute of Physics, Polish Academy of Sciences, Al. Lotników, 32/46, 02-668, Warsaw, Poland.
authors: Jan
authors: J
authors: Fulara
authors: Departement Chemie, Universität Basel, Klingelbergstrasse 80, 4056, Basel, Switzerland.
authors: Arghya
authors: http://orcid.org/0000-0002-6643-9169
authors: A
authors: Chakraborty
authors: Departement Chemie, Universität Basel, Klingelbergstrasse 80, 4056, Basel, Switzerland. j.p.maier@unibas.ch.
authors: John P
authors: JP
authors: Maier
keywords: density functional calculations; electronic spectroscopy; fluorenylium; phenalenylium; reactive intermediates