62154-62-5Relevant academic research and scientific papers
Chemical and Photochemical Water Oxidation by [RuCl(NCNHCO)(DMSO)(py)]-Type Complexes
Su, Wei,Younus, Hussein A.,Chaemchuen, Somboon,Chen, Cheng,Verpoort, Francis
, p. 2565 - 2573 (2017)
In this work, the effects of substitutions in the backbone of imidazolylidene and axial ligands on the reactivity and stability of water-oxidation catalysts were investigated. Three pincer-type asymmetric imidazolium salts NCNHCO, NCNHC-4BrO, and NCNHC-BO (NHC: N-heterocyclic carbene), of which the donating ability of the corresponding imidazolylidene decreases in the same sequence, were prepared. Their application in metalation afforded the corresponding Ru complexes 1 a, 1 b, 2, and 3. It was found that the complexes incorporating the stronger donor displayed lower potential for each redox couple and longer lifetimes, but relatively low reaction rates. Under acidic conditions, water oxidation driven by cerium ammonium nitrate resulted in turnover numbers (TONs) of 2322, 1728, 1928, and 2208 for 1 a, 1 b, 2, and 3, respectively. Complex 2 exhibited a good match of reactivity and stability with a TON of 136 in a typical three-component photocatalysis. Importantly, NHCs could be another powerful tool for tuning the reactivity and stability of water-oxidation catalysts, in addition to substituted pyridines. Rational orchestration of modified NHCs and pyridines could eventually result in water-oxidation catalysts exhibiting appreciable effectiveness and considerable robustness.
Cationic Bis(cyclometalated) Ir(III) Complexes with Pyridine-Carbene Ligands. Photophysical Properties and Photocatalytic Hydrogen Production from Water
Torres, Javier,Carrión, M. Carmen,Leal, Jorge,Jalón, Félix A.,Cuevas, José V.,Rodríguez, Ana M.,Casta?eda, Gregorio,Manzano, Blanca R.
, p. 970 - 984 (2018)
Precursors of chelate pyridine-N-heterocyclic carbene (N^C:) ligands with methyl- or benzyl-substituted imidazolylidene fragments were synthesized. They were used to obtain 12 iridium bis-cyclometalated complexes of the type [Ir(C^N)2(N^C:)]+ (C^N = 2-(phenyl)pyridinato-C2,N, ppy, 2-(4,6-difluorophenyl)pyridinato-C2,N, dfppy). The ancillary N^C: ligands contain different structural modifications. The aim of the work was to analyze the effect that changes in the two types of ligands have on the photophysical and electrochemical properties and also on the behavior of these materials as photosensitizers. The X-ray crystal structures of five complexes were determined. The complexes emitted in the blue-green region. It was expected that the frontier orbitals and thus the photophysical and electrochemical properties would be controlled by the main C^N ligands, and it was demonstrated that the effect of the modifications in the N^C: ligand, especially the presence of a nitro group in the pyridine ring or the interruption of conjugation between the two rings, also affected these properties. The quenching with O2 and photostability studies were also performed. Density functional theory calculations were used to explain the behavior of some derivatives. The complexes and other previously reported compounds were employed as photosensitizers (PS) in preliminary studies on the production of H2 from water using [Co(bpy)3]Cl2 (bpy = 2,2′-bipyridine) as catalyst and triethanolamine (TEOA) as the sacrificial reductant. The absence of quenching of the PS with TEOA allowed us to propose an oxidative quenching mechanism.
Cationic PCP and PCN NHC Core Pincer-Type Mn(I) Complexes: From Synthesis to Catalysis
Buhaibeh, Ruqaya,Duhayon, Carine,Valyaev, Dmitry A.,Sortais, Jean-Baptiste,Canac, Yves
, p. 231 - 241 (2021)
The coordination chemistry of NHC core pincer-type PCP and PCN ligands with a Mn(I) center was systematically investigated. The reaction of [Mn(CO)5Br] with free carbenes, conveniently prepared from the corresponding imidazolium salts and a strong base, leads to the initial formation of bidentate fac-[MnBr(CO)3(κ2P,C,L)] complexes bearing a pending phosphine or pyridine donor extremity (L), which upon bromide abstraction, afford cationic [Mn(CO)3(κ3P,C,L)](OTf) derivatives exhibiting a meridional or a facial coordinating geometry of tridentate NHC core ligand depending on its relative flexibility. All bi- A nd tridentate Mn(I) complexes were characterized by X-ray diffraction analysis. The impact of the tridentate ligand structure on catalytic performance was illustrated in the Mn-catalyzed hydrogenation of acetophenone revealing fac-[Mn(CO)3(κ3P,C,N)](OTf) based on a 5,6-membered metallacyclic architecture to be the most active, thus evidencing the role of the pyridine arm lability in the catalytic cycle.
(Pyridin-2-yl)-NHC Organoruthenium Complexes: Antiproliferative Properties and Reactivity toward Biomolecules
Movassaghi, Sanam,Singh, Sukhjit,Mansur, Aewan,Tong, Kelvin K. H.,Hanif, Muhammad,Holtkamp, Hannah U.,S?hnel, Tilo,Jamieson, Stephen M. F.,Hartinger, Christian G.
supporting information, p. 1575 - 1584 (2018/06/11)
Organoruthenium compounds have been widely investigated for their anticancer activity. Here we use one of the classic ligand classes found in organometallics, i.e., N-heterocyclic carbenes (NHC), and coordinate them to the Ru(η6-p-cymene) scaff
Donor functionalized ruthenium N-heterocyclic carbene complexes in alcohol oxidation reactions
Naziruddin, Abbas Raja,Zhuang, Chun-Shiuan,Lin, Wan-Jung,Hwang, Wen-Shu
, p. 5335 - 5342 (2014/04/03)
N-Pyridyl, N′-amido functionalized imidazolium bromides were obtained in high yields as an N-heterocyclic carbene (NHC) precursor and used as bidentate or a pincer ligands to obtain ruthenium complexes via a silver NHC transmetallation route. The incorporation of a phenyl group as an amido-N substituent (R = Ph) results in a bidentate coordination mode through the C NHC and Npyridyl donors, whereas in its absence (R = H) a pincer coordination mode was observed through the Npyridyl^C NHC^Oamido donors. The ruthenium complex featuring a pincer type NCO coordination mode with a protic NH function adjacent to the coordinating Oamido atom was found to efficiently catalyse the oxidation of activated alcohols effecting quantitative conversions within 30 minutes. However the oxidation of deactivated alcohols required longer reaction times to effect the quantitative transformation. This journal is the Partner Organisations 2014.
