Abstract
AbstractDicationic bis‐quinolinium salts possessing different types of conjugation are presented in which the hetareniums are separated by acetylenic or 1,4‐diethynylbenzene spacers. Cross‐conjugation is induced by interconnections via the 3‐positions of the heteroareniums, and conjugation is realized by 2,2/2,4/4,4‐interconnections. We also synthesized mixed cross‐conjugated/conjugated 2,3/4,3‐interconnected species. The different types of conjugation determine the charge distribution according to the rules of resonance which translate into characteristic 13C NMR as well as UV‐Vis‐spectroscopic properties, LUMO geometries, and chemical properties. We found that the triple bond's resonance frequencies are sensitive 13C NMR spectroscopic indicators for the type of conjugation. Combining cross‐conjugated and conjugated structure elements of dicationic bis‐quinolinium dyes via triple bonds without additional benzene spacer results in considerable bathochromic shifts of the UV‐Vis absorption maxima [Δλmax≈100 nm]. A charge transfer was calculated from the HOMO of the conjugated into the LUMO of the cross‐conjugated partial structure.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call