Theoretical investigation on ruthenium tetraazaporphyrin as potential nitric oxide carrier in biological systems.

Nitric oxide (NO) is an important chemical compound involved in many physiological and pathological processes in living organisms. However, nitric oxide is a very reactive radical that needs to be carried through organisms to reach the desired biological target. With the aim of developing new compounds that can be used as biomedical NO carrier agents we carried out a theoretical investigation at B3LYP/6-31+G(d)/LANL2DZ level on the interaction of NO with RuTAP (Ruthenium tetraazaporphyrin) and Ru(L)TAP, where L=Cl-, NH₃, and Pyridine (Py)) and the oxidation state of Ru ranging from +1 to +3. The theoretical calculation results show that the geometric and electronic parameters of the Ru-NO bond are highly dependent on the oxidation state of Ru and of the chemical nature of ligand L at axial position. The results also show clearly that RuTAP and Ru(L)TAP are good potential candidates to be used as NO carriers in living organisms.