Photochemical reactions of pentaammine(cyanopyridine)ruthenium(II) complexes, [Ru(NH3)5L]2+

An overview of photosubstitution reactions of Ru(II) imine complexes and their application in photobiology and photodynamic therapy

“…In related work, CN bound cyanopyridines of the type [Ru(NH 3 ) 5 (xNC-py)] 2+ (x = 2, 3 or 4) were irradiated in aqueous solution and found to undergo only aquation of the ammine or cyanopyridine ligands and no evidence was found of linkage isomerism. 48 …”

Photoactive ruthenium nitrosyls: Effects of light and potential application as NO donors

“…Also, photosubstitution reactions occur only with a select group of ligands, primarily neutral N donors. For example, ligands such as ammine (NH 3 ) [76,79–82], nitriles (R–C≡N) [83,84] as well as pyridine (py) and related molecules (bpy, phen) [84–86] have been reported in the literature as photoactive ligands. The photochemistry of the ruthenium complexes of these ligands, studied by various groups, constitutes a significant part of the coordination chemistry of ruthenium.…”

Steric and Electronic Factors Associated with the Photoinduced Ligand Exchange of Bidentate Ligands Coordinated to Ru(II)

“…The generally accepted model for photoinduced ligand substitution is the thermal population of low lying 3 LF (ligand field) states from the lowest energy 3 MLCT (metal‐to‐ligand charge transfer) state . The population of the metal‐based 3 LF states in pseudo‐octahedral low‐spin d 6 complexes places electron density on the e g ‐type orbitals with Ru–L( σ *) character, which weakens the bond and results in ligand dissociation .…”

“…Tuning and understanding the excited state properties of new Ru(II) complexes can result in molecules that undergo more efficient ligand dissociation reactions upon irradiation resulting in more effective PCT agents. The generally accepted model for photoinduced ligand substitution is the thermal population of low lying 3 LF (ligand field) states from the lowest energy 3 MLCT (metal-to-ligand charge transfer) state (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). The population of the metal-based 3 LF states in pseudo-octahedral low-spin d 6 complexes places electron density on the e g -type orbitals with Ru-L(r*) character, which weakens the bond and results in ligand dissociation (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17).…”

“…The generally accepted model for photoinduced ligand substitution is the thermal population of low lying 3 LF (ligand field) states from the lowest energy 3 MLCT (metal-to-ligand charge transfer) state (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). The population of the metal-based 3 LF states in pseudo-octahedral low-spin d 6 complexes places electron density on the e g -type orbitals with Ru-L(r*) character, which weakens the bond and results in ligand dissociation (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Although typically the photoinduced ligand exchange in Ru(II) complexes for use in PCT has focused on the dissociation of monodentate ligands (18)(19)(20)(21)(22)(23)(24)(25)(26), it was shown over 20 years ago that introducing bulky aromatic ligands results in photodissociation of a sterically demanding chelate (27).…”