title: Highly strained nonclassical nanotube end-caps. A single-step solution synthesis from strain-free, non-macrocyclic precursors.
abstract: Nonclassical nanotube end-caps have been constructed from strain-free heterocyclic precursors using a one-step synthetic procedure, involving multiple nickel-mediated Ullmann couplings. These systems consist of tubular macrocyclic sections that are tightly capped on one side with a bridging benzene ring, forming deep, chemically accessible cavities. The end-caps are characterized by exceptionally high internal strain energies reaching 144 kcal/mol. The optical absorption and emission properties of these molecules show a marked dependence on conjugation length and geometrical factors. The mechanism of end-cap formation, investigated using DFT calculations, relies on precise timing of transmetalation and reductive elimination events.
authors.affiliation: Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland.
authors.forename: Damian
authors.initials: D
authors.lastname: Myśliwiec
authors.forename: Mateusz
authors.initials: M
authors.lastname: Kondratowicz
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.forename: Piotr J
authors.initials: PJ
authors.lastname: Chmielewski
authors.forename: Marcin
authors.initials: M
authors.lastname: Stępień