A simple aggregation-induced emission-based fluorescence probe (1) for Mg2+ was synthesized by condensation of benzene-1, 2-diamine with 5-bromo-2-hydroxybenzaldehyde, This compound shows favourable character of the AIE-active molecules. More importantly, after addition of Mg2+ to probe (1) in acetonitrile, the solution changed from colorless to yellow colour solution under ultraviolet (UV) radiation obtained from hand-held UV lamp, this finding suggested that probe (1) can be used to detect Mg2+ by colorimetric detection. Detection limit can reach 2.31 × 10−5 M−1. The practical value of the selective and sensitive fluorescence indicators was confirmed by its application to detection of magnesium ion in acetonitrile.

The allylation reactions of aromatic aldehydes and ketones were carried out in 31–86% yield using SnCl2–H2O system under ultrasound irradiation at r.t. for 5 h. The reactions in the same system gave homoallyl alcohols in 21–84% yield with stirring at r.t. for 24 h. Compared with traditional stirring methods, ultrasonic irradiation is more convenient and efficient.