A new strategy for neurochemical photodelivery: metal-ligand heterolytic cleavage.

A new strategy to build caged-compounds is presented. The approach is based on heterolytic photocleavage of a metal-ligand bond in a coordination compound. A ruthenium polypyridine complex, containing the neurocompound 4-amino pyridine (4AP) is used as the core of the phototrigger. The biomolecule is released by irradiation with visible light (>480 nm). The liberated 4AP promotes the activation of a leech neuron by means of blocking its K+ channels. The syntesis, characterization, and the inherent advantages of this method are discussed.