Physicochemical Analysis of Ruthenium(II) Sensitizers of 1,2,3-Triazole-Derived Mesoionic Carbene and Cyclometalating Ligands

Abstract

A series of heteroleptic bis(tridentate) ruthenium(II) complexes bearing ligands featuring 1,2,3-triazolide and 1,2,3-triazolylidene units are presented. The synthesis of the C^N^N-coordinated ruthenium(II) triazolide complex is achieved by direct C-H activation, which is enabled by the use of a 1,5-disubstituted triazole. By postcomplexation alkylation, the ruthenium(II) 1,2,3-triazolide complex can be converted to the corresponding 1,2,3-triazolylidene complex. Additionally, a ruthenium(II) complex featuring a C^N^C-coordinating bis(1,2,3-triazolylidene)pyridine ligand is prepared via transmetalation from a silver(I) triazolylidene precursor. The electronic consequences of the carbanion and mesoionic carbene donors are studied both experimentally and computationally. The presented complexes exhibit a broad absorption in the visible region as well as long lifetimes of the charge-separated excited state suggesting their application in photoredox catalysis and photovoltaics. Testing of the dyes in a conventional dye-sensitized solar cell (DSSC) generates, however, only modest power conversion efficiencies (PCEs).

Ruthenium-Catalyzed Azide Alkyne Cycloaddition Reaction: Scope, Mechanism, and Applications

“…250 Comparing structure 145 with its 1,4-disubstituted counterpart (Scheme 58), the authors found significant differences in the spectral properties of the molecules, where blue shifts for 145 relative to the corresponding 1,4-isomer in the absorption and emission spectra were attributed to a lesser degree of conjugation in Ruthenium(II) polypyridyl complexes, where one or two pyridyl ligands were replaced by 1,5-disubstituted triazoles, were synthesized by Schubert and co-workers, 252 and alkylation of the triazoles with methyl iodide also gave access to ruthenium triazolylidene complexes. The electrochemical and photochemical properties of 146-148 ( Fig.…”

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry

“…Heteroleptic Ru(II) complexes with carboxylate-appended terpy of 52 only gave modest power conversions. 153 Anionic 1,2,3-triazolate derivatives of btp have also been reported, such as 53. These ligands have increased s-and p-donor strengths, shifting the MLCT of Ru(II) complexes to longer wavelengths.…”

Azide Chemistry – An Inorganic Perspective, Part II[‡][3+2]‐Cycloaddition Reactions of Metal Azides and Related Systems

“…[418] Functionalized bis-1,2,3-triazole "click" ligands with a spacer between the two heterocycles have been shown to self-assemble with palladium(II) into quadruply stranded cages where two palladium ions and two bis-triazoles form a rectangle. [419] Ruthenium(II) complexes of 1,2,3-triazolate based tridendate ligands show promising properties for their use as dyes in solar cells. [420] 1,2,3-Triazoles and derivatives are a special class of heterocycles with a broad spectrum of applications.…”