NO donors cis-[Ru(bpy)2(L)NO]3+ and [Fe(CN)4(L)NO]− complexes immobilized on modified mesoporous silica spheres

The reaction of [Ru(bpy)2Cl2] and Na2[Fe(CN)4(dmso)2] complexes with isonicotinic acid immobilized on silica spheres (Si-ATPS-ISN) followed by a NO bubbling produced Si-ATPS-ISN-[Ru(bpy)2(NO)] (system I) and Si-ATPS-ISN-[Fe(CN)4(NO)] (system II). The characterization of these systems was carried out by UV–Vis, FTIR spectroscopy and electrochemical techniques. As judged by the FTIR data, the nitric oxide ligand has an NO+ character in both systems (ν(NO+): 1938 cm−1). The NO release, which was monitored by means of FTIR, electrochemistry, and NO sensor electrode, was observed for both systems upon white light irradiation and chemical reduction by cysteine. These results indicated that the system (II) presents a higher potential for controlled NO release. The characterization (FTIR and UV–Vis) of the systems after the NO release suggested the formation of the aqua systems ATPS-ISN-[Ru(bpy)2(OH2)] and ATPS-ISN-[Ru(bpy)2(OH2)].

Graphical abstractNO release was observed by using [Ru(bpy)2Cl2] and Na2[Fe(CN)4(dmso)2] complexes immobilized on silica spheres modified with isonicotinic acid. A higher potential for controlled release is suggested for the iron complex based on the observation of a sluggish kinetics of NO liberation.Figure optionsDownload full-size imageDownload as PowerPoint slide