Synthesis and Spectroscopic Properties of the Elusive 3a,9a-Diazaperylenium Dication
journal contributionposted on 16.10.2002, 00:00 by Chariklia Sotiriou-Leventis, Abdel-Monem M. Rawashdeh, Woon Su Oh, Nicholas Leventis
The 3a,9a-diazaperylenium dication (1) was synthesized for the first time in two steps from p-phenylene diamine. Ab initio calculations show a twisted ground state with a 6.4° tilt between the two quinolizinium building blocks. Dication 1 is photoluminescent in fluid solutions of H2O, CH3CN, and CH3NO2, but not in rigid matrices of the same solvents. This phenomenon has been attributed to a geometric relaxation of the tilted ground state into an emitting planar lowest singlet excited state.