Ruthenium Nitrosyl Complexes: Photoinduced Delivery of NO to Different Biological Targets

Abstract

Nitric oxide (NO) molecule participates in various biological events such as vasodilation, neurotransmission, antioxidant, and immune responses. In living organisms, it is generated as a side product by nitric oxide synthase (NOS) enzyme via conversion of L-arginine to L-citrulline. The physiological role of NO is concentration-dependent, which is crucially important to obtain the desired effects in biosystem. Coordination complexes of NO with transition metals, especially ruthenium (Ru), have gained increasing interest for the past few decades. So far, several ruthenium nitrosyl complexes have been developed as NO carriers, and their photochemical properties are well documented in the literature. Most of the ruthenium nitrosyl (Ru–NO) complexes are found photolabile in nature and release NO molecule in the presence of the light of suitable wavelength. The photoreleased NO can stimulate various biological targets in different in-vitro and in-vivo models. The main motif of this book chapter is to cover majority of the light sensitive Ru–NO complexes, and the photochemical properties of these complexes, quantification, delivery and application of NO molecule for various biological targets are discussed at a length.