This article describes the switchable fluorescence of a series of donor–acceptor type 2,2′-bipyridines. The original bipyridine molecules have four protonation sites – two on the amino donor sites and two on the pyridine acceptor cores. These nitrogen-containing sites are selectively protonated by suitable acids and the protonation influences the electronic conjugation and structure of the chromophores. Consequently, the emission characteristics of the molecules are affected, and this behaviour is reversible, i.e. the neutral original species are regenerated by the addition of an equivalent amount of base. The switchable behaviour of these compounds is accompanied by a visible colour change of the relevant solutions.

本文描述了一系列供体-受体类型 2,2'-联吡啶的可切换荧光。最初的联吡啶分子有四个质子化位点——两个在氨基供体位点，两个在吡啶受体核心。这些含氮位点被合适的酸选择性质子化，质子化影响电子共轭和发色团的结构。因此，分子的发射特性受到影响，并且这种行为是可逆的，即通过添加等量的碱来再生中性原始物种。这些化合物的可切换行为伴随着相关溶液的可见颜色变化。