Proacetylenic reactivity of a push-pull buta-1,2,3-triene: New chromophores and supramolecular systems

Abstract

Proacetylenic: An aniline-based donor-acceptor-substituted butatriene exhibits not only cumulene-like dimerization to give a [4]radialene (λ max=756 nm), but also acetylene-like (proacetylenic) reactivity towards tetracyanoethene, affording via [2+2] cycloaddition- cycloreversion a NIR-absorbing zwitterionic chromophore (λ max= 825 nm). The cationic charge on the imminium-type nitrogen in the zwitterion is evidenced by host-guest complexation with a tetraphosphonate cavitand. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.