Solvent- and DNA-Controlled Phototriggered Linkage Isomerization in a Ruthenium Sulfoxide Complex Incorporating Dipyrido[3,2-a:2′,3′-c]phenazine (dppz)

Abstract

A new tris-heteroleptic complex [Ru(bpy)(dppz)(OSO)](ClO), [1](ClO) (bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine and OSO = 2-methylsulfinylbenzoate), was synthesized and characterized to control the photochromic Ru-S → Ru-O linkage isomerization. Details isomerization kinetics studied by UV-visible absorption spectroscopy and cyclic voltammetry revealed that efficient photochromic S → O isomerization and thermal O → S reversal take place in solvents like propylene carbonate (PC), methanol, and dichloromethane. Strikingly, photoisomerization of [1](ClO) is arrested in water although is active in the analogous compound [Ru(bpy)(OSO)](ClO). Effective excited state deactivation through dark MLCT state involving dppz ligand of [1](ClO) switches off photochromism in aqueous medium. Interestingly, the photochromism is activated in aqueous solution in the presence of DNA which shields the dppz localized dark state through intercalation. Ultrafast transient absorption spectroscopic measurement sheds light on the differential behavior of photochromism in aqueous and nonaqueous solvents.

Anti-bacterial, anti-biofilm and synergistic effects of phenazine-based ruthenium(ii) complexes

“…However, it was only partially characterized and no biological studies were ever reported. 60,61 High-resolution mass spectrometry showed a peak at m/z of 575.0331 with a typical isotopic abundance of ruthenium that corresponded to the [Ru(bpy)(dppz)Cl] + ion (theoretical m/z = 575.0325), supporting the presence of both distinct chelating ligands. Further characterizations were consistent with the formulation, as shown in the ESI (Fig.…”