A caged nicotine with nanosecond range kinetics and visible light sensitivity.

We report the synthesis, characterization and applications of a ruthenium-bipyridine based caged nicotine. The complex [Ru(bpy)(2)(nic)(2)](2+) (where bpy = 2,2' bipyridine and nic = nicotine (3-[(2S)-1-methylpyrrolidin-2-yl] pyridine)) releases nicotine with a quantum yield ϕ = 0.23 upon irradiation with biologically harmless, blue (473 nm) or green (532 nm) light. The photolysis reaction is clean and very fast, with a time constant of 17 ns. The synthesis is simple and the obtained compound is characterized by NMR, UV-Vis spectroscopy and cyclic voltammetry. We find that this compound is active in biological systems, being able to elicit action potentials in leech neurons.