It is all About That Base: Simply by switching the base it is possible to access both bis(aroyl-S,N-ketene acetals) as well as diethylamino-aroyl-S,N-ketene acetals. The latter show strong solid-state emission as well as outstanding aggregation-induced emission properties thus conveying a 53-fold increase in emission intensity.

Abstract

Donor-substituted aroyl-S,N-ketene acetals can be rapidly obtained by nucleophilic attack of triethylamine at the acid chloride with concomitant decarbonylation followed by addition-elimination reaction of in situ generated enamines. These potent chromophores exhibit intensive solid-state emission and pronounced AIE (aggregation-induced emission) characteristics with high quantum yields. By changing the base to diisopropylethylamine, enlarged aroyl-S,N-ketene acetal bi- and trichromophores are easily accessible.