title: Single-component organic semiconductors based on novel radicals that exhibit electrochemical amphotericity: preparation, crystal structures, and solid-state properties of N,N'-dicyanopyrazinonaphthoquinodiiminides substituted with an N-alkylpyridinium unit.
abstract: N,N'-Dicyanonaphthoquinodiimines fused with a pyrazine ring 1 were prepared from the corresponding quinones 4. The new acceptors 1 have a planar pi-system and undergo reversible two-stage 1e-reduction. Quaternization of the pyridyl substituent in 1d-f gave pyridinium derivatives 2d+, 2e+, and R-3+, respectively, which are stronger acceptors that undergo three-stage 1e-reduction. Upon electrochemical reduction of these cations, novel radicals 2d., 2e., and R-3. were generated and isolated as stable solids. The molecular geometries determined by X-ray analysis indicated that these radicals adopt a zwitterionic structure, in which the unpaired electron is located on the quinodiimine unit but not on the pyridyl group. These novel radicals undergo facile and reversible 1e-oxidation as well as two-stage 1e-reduction. The observed amphotericity endows the radicals with electrical conductivities (10(-5) to 10(-9) S cm-1), and these thus represent a new motif for single-component organic semiconductors.
authors: Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors: T
authors: T
authors: Suzuki
authors: S
authors: S
authors: Miyanari
authors: Y
authors: Y
authors: Tsubata
authors: T
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authors: Fukushima
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authors: Miyashi
authors: Y
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authors: Yamashita
authors: K
authors: K
authors: Imaeda
authors: T
authors: T
authors: Ishida
authors: T
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authors: Nogami