NOVEL ORGANIC IONS OF HIGH-SPIN STATES - ESR DETECTION OF A MONOANION OF META-PHENYLENEBIS(PHENYLMETHYLENE)

1,3-Bis(α-diazobenzyl)benzene (1,3-BDB), known as the precursor of the spin-quintet m-phenylenebis(phenylmethylene) (m-PBPM), has been subject to a sequential treatment of γ-radiolysis followed by photolysis in 2-methyltetrahydrofuran at 77 K. ESR and optical measurements indicate the formation of a monoanion of m-PBPM. The spin multiplicity in the ground state is doublet but is quartet in the first excited state, the energy gap between the two states being only 4.5 ± 0.5 cm-1 as estimated from the temperature dependence of the ESR signal over 3.1-77 K. The present work seems to be the first report of the electronically charged hydrocarbon with high-spin states. © 1990, American Chemical Society. All rights reserved.