Electrochemical, photophysical and photochemical properties of a hexanuclear ruthenium(II) bis(2,2′-bipyridyl) complex containing a tris(pyrazyltriazole)benzene ligand

Ground- and Excited-State Electronic Structure of an Emissive Pyrazine-Bridged Ruthenium(II) Dinuclear Complex

“…the dipyridopyrazine family of complexes), are pyrazine-based; however, few detailed studies have been carried out to confirm this 6f. The emission spectra of 1 and H 2 1 are comparable with those reported for the related complexes (see Figure and Table ) [Ru(bpy) 2 (μ-1Mepztr)Ru(bpy) 2 Cl] 3+ ( 6 ) 13e and [(Ru(bpy) 2 ) 3 ((pztr) 3 ph)(Ru(bpy) 2 Cl) 3 ] 6+ ( 8 ) . The red shift observed upon protonation is in agreement with the stabilization of the pyrazine-based LUMO; however, assignment of the emitting state as pyrazine-based is not so clear since a significant isotope effect on the emission lifetimes for 1 and H 2 1 (at 298 and 77 K) is observed upon deuteriation of the bpy ligands (Table ).…”

“…6f The emission spectra of 1 and H 2 1 are comparable with those reported for the related complexes (see Figure 2 and Table 1) [Ru(bpy) 2 (µ-1Mepztr)Ru(bpy) 2 Cl] 3+ (6) 13e and [(Ru(bpy) 2 ) 3 ((pztr) 3 ph)(Ru(bpy) 2 Cl) 3 ] 6+ (8). 49 The red shift observed upon protonation is in agreement with the stabilization of the pyrazine-based LUMO; however, assignment of the emitting state as pyrazine-based is not so clear since a significant isotope effect on the emission lifetimes for 1 and H 2 1 (at 298 and 77 K) is observed upon deuteriation of the bpy ligands (Table 1). In previous studies of heteroleptic complexes, deuteriation of the ligands on which the lowest excited state is based results in an increase in emission lifetime.…”

Effect of Deprotonation of a Benzimidazolyl Ligand on the Redox Potential and the Structures of Mononuclear Ruthenium(II) Complexes

“…300-350 mV per proton) of the redox potentials reported for ruthenium, osmium and iron complexes with the ligands bearing multi-imidazolyl and -benzimidazolyl units, [9,[14][15][16] but similar to the shift (350-420 mV) of the Ru II /Ru III oxidation potentials reported for monoruthenium complexes with two bpy ligands and one triazole-or pyrazole-containing ligand. [21,23,29,30] …”

“…[13][14][15][16][17][18][19] In addition to the imidazole-containing ligands, mono-and dinuclear ruthenium complexes with ligands bearing triazole and pyrazole units were also extensively studied for their interesting electrochemical and photophysical properties. [20][21][22][23][24] In this communication, we …”

Mononuclear and Binuclear Ruthenium(II) Complexes Containing 2,2‘-Bipyridine or 1,10-Phenanthroline and Pyrazole-3,5-Bis(benzimidazole). Synthesis, Structure, Isomerism, Spectroscopy, and Proton-Coupled Redox Activity

“…Ruthenium(II) and osmium(II) complexes of this sort of ligand are of considerable interest because their redox, absorption, and emission properties can be subjected to fine-tuning by control of pH. Indeed, in a few cases proton-induced switching phenomena have been reported. , To this end, complexes of the bridging ligands 2,2‘-bis(2-pyridyl)bibenzimidazole, , 2,6-bis(2‘-pyridyl)benzdiimidazole, 16b, 2,2‘-bis(2-benzimidazolyl)-4,4‘-bipyridine, , 1,3,5-tris[5-(pyridin-2-yl)-1,2,4-triazol-3-yl]benzene, and 1,3,5-tris[5-(pyrazin-2-yl)-1,2,4-triazol-3-yl]benzene 18 in combination with 2,2‘-bipyridine (bpy) or 1,10-phenanthroline (phen) have been studied extensively.…”