A light-responsive molecular switch based on cucurbit[7]uril and 1,1′-bis(benzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium dibromide displaying white light emission

Abstract

By using ¹H NMR, ESI-MS and UV spectra, a novel light-responsive molecular switch constructed using 1,1′-bis(benzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium (1²⁺) and cucurbit[7]uril (Q[7]) is demonstrated. The E- to Z-isomerization of the double bond in 1²⁺ results in the transition of the switching states from the 1 : 2 complex E-1²⁺@Q[7]₂ to the stable 1 : 1 complex Z-1²⁺@Q[7]. In particular, both the 1 : 2 complex and the 1 : 1 complex can emit cold white fluorescence under UV light.