Alkynylated and triazole-linked aroyl-S,N-ketene acetals: one-pot synthesis of solid-state emissive dyes with aggregation-induced enhanced emission characteristics.

Alkynylated aroyl-S,N-ketene acetals are readily synthesized in mostly excellent yields by a Sonogashira reaction resulting in a substance library of more than 20 examples. Upon expansion of the reaction sequence by deprotection and concatenating of the copper-click reaction in a one-pot fashion, a library of 11 triazole-ligated aroyl-S,N-ketene acetals is readily accessible. All derivatives show pronounced solid-state emission and aggregation-induced emission properties depending on the nature of the alkynyl or the triazole substituents.

Diaroyl-S,N-ketene Acetals: Red-Shifted Solid-State and Aggregation-Induced Emitters from a One-Pot Synthesis.

Symmetric and unsymmetric diaroyl-S,N-ketene acetals can be readily accessed in consecutive syntheses in good to excellent yields by exploiting the inherent nucleophilic character of the methine position. Different aroyl-S,N-ketene acetals as well as acid chlorides yield a library of 19 diaroyl compounds with substitution and linker pattern-tunable emission properties, leading to a significant red-shift of emission in the solid and aggregated state, which was thoroughly investigated. Additionally, the stability of the luminescent aggregates is highly increased. In a follow-up one-pot procedure, pyrazolo-S,N-ketene acetals can easily be accessed employing a nucleophilic cyclocondensation.