Further Observations on Water Oxidation Catalyzed by Mononuclear Ru(II) Complexes
摘要:
A family of 28 mononuclear Ru(II) complexes have been prepared and characterized by H-1 NMR, electronic absorption, and cyclic voltammetry. These complexes are studied as catalysts for water oxidation. All the catalysts possess one tridentate ligand, closely related to 2,2';6,2 ''-terpyridine (tpy) and may be divided into two basic types. In the type-1 catalyst, the three remaining coordination sites are occupied by a bidentate closely related to 2,2'-bipyridine (bpy) and a monodentate halogen (Br, Cl, or I) or water molecule. In the type-2 catalyst, the three remaining coordination sites are occupied by two axial 4-picoline molecules and an equatorial halogen or water. In general the type-2 catalysts are more reactive than the type-1. The type-2 iodo-catalyst shows first-order behavior and, unlike the bromo- and chloro-catalysts, does not require water-halogen exchange to show good activity. The importance of steric strain and hindrance around the metal center is examined. The introduction of three t-butyl groups at the 4, 4', and 4 '' positions of tpy sometimes improves catalyst activity, but the effect does not appear to be additive.
Further Observations on Water Oxidation Catalyzed by Mononuclear Ru(II) Complexes
摘要:
A family of 28 mononuclear Ru(II) complexes have been prepared and characterized by H-1 NMR, electronic absorption, and cyclic voltammetry. These complexes are studied as catalysts for water oxidation. All the catalysts possess one tridentate ligand, closely related to 2,2';6,2 ''-terpyridine (tpy) and may be divided into two basic types. In the type-1 catalyst, the three remaining coordination sites are occupied by a bidentate closely related to 2,2'-bipyridine (bpy) and a monodentate halogen (Br, Cl, or I) or water molecule. In the type-2 catalyst, the three remaining coordination sites are occupied by two axial 4-picoline molecules and an equatorial halogen or water. In general the type-2 catalysts are more reactive than the type-1. The type-2 iodo-catalyst shows first-order behavior and, unlike the bromo- and chloro-catalysts, does not require water-halogen exchange to show good activity. The importance of steric strain and hindrance around the metal center is examined. The introduction of three t-butyl groups at the 4, 4', and 4 '' positions of tpy sometimes improves catalyst activity, but the effect does not appear to be additive.
Electrochemical, Spectroscopic, and Computational Investigation of a Series of Polypyridyl Ruthenium(II) Complexes: Characterization of Reduced States
作者:Nicolas Queyriaux、Charlène Esmieu、Arvind K. Gupta、Laure Vendier、Sascha Ott、Maylis Orio、Leif Hammarström
DOI:10.1002/ejic.202001165
日期:2021.4.8
A series of polypyridyl ruthenium(II) complexes has been synthesized and characterized by 1H‐NMR, electronic absorption and voltammetric techniques. Among this series, hexafluorophosphate salts of eight ruthenium(II) complexes were newly prepared. Due to the well‐known ability of this class of compounds to assist electro‐ and photocatalytic reductive processes (such as the reduction of CO2, H+ and
Preparation and characterization of ruthenium complexes with the new 4,4′,4″-tri-tert-butylterpyridine ligand and with 4,4′-di-tert-butylbipyridine
作者:T.Ben Hadda、H. Le Bozec
DOI:10.1016/s0277-5387(00)86335-4
日期:——
Strong and weak coupling in mixed-valence complexes bridged by 4,4′-azo-di(phenylcyanamido)
作者:Mousa Al-Noaimi、Robert J. Crutchley
DOI:10.1016/j.ica.2007.02.039
日期:2007.6
The complexes [Ru(tpy*)(bpy)}(2)(mu-adpc)][PF6](2) where tpy* is 4,4',4"-tri-(tert-butyl)-2,2':6',2"-terpyridine, bpy is 2,2'-bipyridine, and adpc(2-) is 4,4'-azo-diphenyleyanamide dianion and trans, trans-[Ru(tpy*)(pc))(2)(mu-adpc)] where pc(-) is 2-pyrazine-carboxylato were prepared and characterized by cyclic voltammetry and spectroelectrochemical methods. Intervalence band properties and IR spectroelectrochemistry of the mixed-valence complexes [Ru(tpy*)(bpy)}(2)(mu-adpc)](3+) and trans, trans-[Ru(tpy*)(pc)}(2)(mu-adpc)](+) are consistent with delocalized and valence-trapped mixed-valence properties respectively. The reduction in mixed-valence coupling upon substituting a bipyridine ligand with 2-pyrazine carboxylato strongly suggests that hole-transfer superexchange is the dominant mechanism for metal-metal coupling in these complexes. (c) 2007 Elsevier B.V. All rights reserved.