Synthesis of N,N′,N″-Triaryl Tris(3-aminopropyl)amine Derivatives and Their Study as Fluorescent Sensors for Metal Cations

Palladium-catalyzed arylation of tris(3-aminopropyl)amine (TRPN) with a number of aryl halides, including 1- and 2-bromonaphthalenes, 1- and 2-chloroanthracenes, 9-bromoanthracene, 9-bromophenanthrene, and 1-bromopyrene, afforded the corresponding N,N′,N″-triaryl derivatives. Almost quantitative yields of the target products were obtained in the reactions with 1-chloro- and 9-bromoanthracenes. Study of the fluorescence spectra of the synthesized compounds in the presence of different metal salts revealed complete or very strong fluorescence quenching of naphthalen-1-yl, anthracen-2-yl, and phenanthren-9-yl derivatives upon addition of Cu(II), Al(III), and Cr(III) perchlorates. Complete fluorescence quenching of pyren-1-yl derivative was observed on in the presence of copper ions. Some other metal cations induced small changes in the emission intensity with a blue shift of the fluorescence maximum by about 10 nm. Characteristic changes in the electronic absorption spectra of napththalen-1-yl, anthracen-9-yl, and pyren-1-yl derivatives in the presence of Cu(II), Al(III), and Cr(III) ions make these compounds promising for fluorescent and spectrophotometric detection of Cu(II), Al(III), and Cr(III) ions.