title: Synthesis and properties of cycloparaphenylene-2,5-pyridylidene: a nitrogen-containing carbon nanoring.
abstract: The first synthesis of a nitrogen-containing cycloparaphenylene, cyclo[14]paraphenylene[4]2,5-pyridylidene ([14,4]CPPy), has been achieved. A palladium-catalyzed stepwise assembly of 2,2'-bipyridine, benzene, and L-shaped cyclohexane units, followed by NaHSO(4)/o-chloranil-mediated aromatization, successfully provided [14,4]CPPy. While the absorption and fluorescence properties of [14,4]CPPy were somewhat similar to those of cycloparaphenylenes (λ(abs) = 344 nm, ε = 7.3 × 10(4) cm(-1) M(-1), λ(em) = 427 nm, Φ(F) = 0.80), it was found that [14,4]CPPy possesses an interesting halochromic property.
authors.affiliation: Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan.
authors.forename: Katsuma
authors.initials: K
authors.lastname: Matsui
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Segawa
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Itami