Understanding Electronic Ligand Perturbation over Successive Metal‐Based Redox Potentials in Mononuclear Ruthenium–Aqua Complexes

Abstract

A family of new ruthenium complexes containing a combination of polypyridyl and carbene ligands has been prepared and characterized from structural, spectroscopic, and redox viewpoints both experimentally and computationally. Interestingly, a correlation between ΔE1/2, defined as the difference between E1/2(RuIV/III) and E1/2(RuIII/II), and the activity and selectivity of some catalytic oxidation processes has been clearly established. A density functional theory study on the synthesized species has been carried out revealing a correlation between the number of carbene ligands and ΔE1/2, and consequently with the RuIII disproportionation. The reactivity of these complexes has been tested with regard to the electrocatalytic oxidation of benzyl alcohol.

Mechanistic analysis of water oxidation catalyzed by mononuclear copper in aqueous bicarbonate solutions

“…[1][2][3][4][5][6][7][8][9] Many transitionmetal-based homogeneous catalysts for water oxidation have been reported, especially those incorporating Ir [10][11][12][13][14] and Ru. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Reports of homogeneous catalysts based on more earth-abundant metals, [30][31][32] e.g., Mn, [33][34][35][36] Co, [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] Fe,…”

Role of ligands in catalytic water oxidation by mononuclear ruthenium complexes

“…However, this feature is absent for the carbene complex 8d because its oxidized species [Ru III -OH 2 ] 3+ coordinates CH 3 COO -or HPO 4 2-, forming 2+ . More recently, Llobet and co-workers have also reported a series of mononuclear aqua-Ru complexes containing a different combination of carbene/pyridyl ligands [ 45 ]. They revealed an interesting linear correlation between the number of carbene ligands in the complexes and ΔE 1/2 where each carbene unit causes a 100 mV decrease in the ΔE 1/2 value.…”

“Pincer” Pyridine–Dicarbene–Iridium and ‐Ruthenium Complexes and Derivatives Thereof

“…In attempts to access new Ru catalyst precursors of type B 0 , we targeted complexes (neutral or cationic) with labile and/or easily removable co‐ligands under catalytic conditions. The recently described cationic butyronitrile and acetonitrile species with 4‐G‐pyridine‐bis(benzimidazol‐2‐ylidene) and ‐bis(imidazol‐2‐ylidene) (G = H, OMe, OH[15c], [15d]) pincers are the known representatives of this family of complexes; a dozen of bipy‐substituted complexes of type B 0 have been studied as electrocatalysts for the reduction of CO 2 …”