Radical Cations of Bilayer Nanographenes

Chemical redox reactions of bilayer nanographene complexes, (C96H24Ar6)(2) (Ar = 2,6-dimethylphenyl) (1(2)) and (C42H12R6)(2) (R = Bu-t) (2(2)), were investigated. Upon two-electron oxidation reactions, 1(2) and 2(2) were transformed to radical cations 1(2)(2 center dot+) and 2(2)(2 center dot+), respectively. SQUID and EPR measurements on 1(2)(2 center dot+) and 2(2)(2 center dot+) indicate that they possess an open-shell singlet ground state with antiferromagnetic interactions between two layers. The shortest separation distance between bilayers in 2(2)(2 center dot+) (3.30 & Aring;) is shorter than that in 2(2) (3.44 & Aring;) and 2(2)(center dot+) (3.40 & Aring;), illustrating stronger interaction upon loss of electrons.