Synthesis, Characterization, and Crystal Structures of 1,1-Disubstituted-2,3,4,5-tetraphenylgermoles That Exhibit Aggregation-Induced Emission

A series of 2,3,4,5-tetraphenylgermoles with different 1,1-substituents have been prepared, and their UV–vis absorption and fluorescence spectral profiles in solution were determined. A thin-layer chromatography based method was used to measure their solid-state luminescence. Nine of the 11 new germoles have been characterized crystallographically. The aggregation-induced emission effect in these germoles was studied, and significant enhancement of the photoluminescence and quantum yield in mixed solvent–water systems was determined. Scanning and transmission electron microscopy analysis revealed the formation of nanocrystalline aggregates in the mixed solvent–water systems and after exposure of the germoles to acetone, a volatile organic chemical.