Chemiluminescence of Lanthanide Ions Ln(n – 1)+ during Reduction of Lnn+ with a Solvated Electron

The ability of lanthanide ions to luminescence due to the chemical generation of electronically excited states *Ln ( n ‒ 1)+ upon reduction of Ln n + by a solvated electron in ultrasound-irradiated solutions has been demonstrated for the first time using Eu 3+ and Ce 4+ as an example. A solvated electron is formed by injection of electrons from a nonequilibrium plasma periodically generated by ultrasound in a moving bubble. The key stage of the found single-bubble sonochemiluminescence (SCL) is the reduction of Eu 3+ and Ce 4+ to, respectively, the bivalent and trivalent states by an electron solvated in water and ethylene glycol. It has been found that the SCL emitters are excited ions *Eu 2+ and *Ce 3+ , which have, along with the ability to luminescence, high reducing properties ( E ox ≤ –2.9 V). The latter factor determines the possibility of using ultrasonic generation of *Eu 2+ and *Ce 3+ in numerous reactions of organic synthesis and metal complex catalysis.