Linear Conjugated Systems Bearing Aromatic Terminal Groups. V. Syntheses and Electronic Spectra of 2,2′-, 3,3′-, and 9,9′-Diphenanthrylpoly-ynes

Abstract 2,2′-, 3,3′-, and 9,9′-Diphenanthrylpoly-ynes (Vn, VIn, and VIIn, n=1–6) were synthesized and their electronic spectra were measured. It was found that the longest-wavelength absorption maxima (λmax) in the spectra of each series of the diphenanthrylpoly-ynes (Vn, VIn and VIIn) shift linearly with the xth power of the number of acetylenic bond (n), [λmax∝nx], being x=1.3 for Vn and x=1.4 for VIn and VIIn.