81998-03-0Relevant articles and documents
A series of dinuclear copper complexes bridged by phosphanylbipyridine ligands: Synthesis, structural characterization and electrochemistry
Lilio, Alyssia M.,Grice, Kyle A.,Kubiak, Clifford P.
, p. 4016 - 4023 (2013)
The phosphanylbipyridine ligands 6-(diphenylphosphanyl)-4,4'-dimethyl-2,2'- bipyridine (PPh2-Me2-bipy, a), 4,4'-di-tertbutyl-6- (diphenylphosphanyl)-2,2'-bipyridine (PPh2-t Bu2- bipy, b), and 6-(diisopropylphosphanyl)-2,2'-bipyridine (PiPr2bipy, c) and the corresponding dinuclear copper complexes [Cu2(μ-PPh 2-Me2-bipy)2(NCCH3) 2](PF6)2 (1), [Cu2(μ-PPh 2-t Bu2-bipy)2(NCCH3) 2](PF6)2 (2), [Cu2(μ-PiPr 2bipy)2(μ-NCCH3)](PF6) 2 (3), and [Cu2(μ-PiPr2bipy) 2{μ-CNCH(CH3)2}]-(PF6) 2 (4) were synthesized. The X-ray structures of 1-4 show that the complexes are dinuclear with the bidentate bipyridine coordinating to one copper atom and the phosphane moiety coordinating the other copper center. Complexes 3 and 4 possess short Cu-Cu distances with bridging acetonitrile and isocyanide ligands. The cyclic voltammograms of 1-4 were examined under N2 and CO2. Under N2, 1-3 show four quasi-reversible 1e - reductions, and under CO2, they show current enhancement at the second reduction. In comparison, complex 4 shows four irreversible reductions under N2 and no current enhancement under CO2.
Synthesis and catalytic water oxidation activities of ruthenium complexes containing neutral ligands
Xu, Yunhua,Duan, Lele,Akermark, Torbjoern,Tong, Lianpeng,Lee, Bao-Lin,Zhang, Rong,Akermark, Bjoern,Sun, Licheng
, p. 9520 - 9528 (2011)
Two dinuclear and one mononuclear ruthenium complexes containing neutral polypyridyl ligands have been synthesised as pre-water oxidation catalysts and characterised by 1H and 13C NMR spectroscopy and ESI-MS. Their catalytic water oxidation properties in the presence of [Ce(NH 4)2(NO3)6] (CeIV) as oxidant at pH 1.0 have been investigated. At low concentrations of Ce IV (5 mM), high turnover numbers of up to 4500 have been achieved. An 18O-labelling experiment established that both O atoms in the evolved O2 originate from water. Combined electrochemical study and electrospray ionisation mass spectrometric analysis suggest that ligand exchange between coordinated 4-picoline and free water produces Ru aquo species as the real water oxidation catalysts. Copyright
Cobalt Complex with Redox-Active Imino Bipyridyl Ligand for Electrocatalytic Reduction of Carbon Dioxide to Formate
Liu, Fang-Wei,Bi, Jiaojiao,Sun, Yuanyuan,Luo, Shuping,Kang, Peng
, p. 1656 - 1663 (2018/05/08)
An imino bipyridine cobalt(II) complex was developed for the electrocatalytic reduction of CO2 to formate in acetonitrile with a faradaic efficiency of approximately 80 %. For comparison, a symmetric bis-imino pyridine complex showed lower catalytic activity because of less conjugation in the system. Cyclic voltammetry, electron paramagnetic resonance and IR spectroscopy studies provided mechanistic details and the structures of the key intermediates. DFT calculations confirmed the role of large π-conjugated groups for stabilizing key intermediates through electronic conjugation.
2,2′-Homocoupled Azine N,N′-Dioxides or Azine N-Oxides: CDC- or SNAr-Controlled Chemoselectivity
Jha, Abadh Kishor,Jain, Nidhi
, p. 4765 - 4772 (2017/09/07)
An unprecedented Cu(OAc)2- and LiOtBu-mediated homocoupling of azine N-oxides to yield 2,2′-azine N,N′-dioxides is reported. This is the first instance in which copper has been used to catalyze the homodimerization reaction, especially of 2-phenylpyridine N-oxides. In the absence of catalytic copper, the reaction follows an alternative pathway, and instead of dioxides it yields 2,2′-azine N-monoxides. This latter protocol works efficiently with a range of N-heterocyclic oxides of pyridine, 2-phenylpyridine, quinoline and N-aryl-1,2,3-triazole. It is scalable, offers high regioselectivity and gives the products in moderate to high yields. The observed chemoselectivity between the copper-assisted and copper-free protocols is routed through oxidative cross-dehydrogenative coupling (CDC) and nucleophilic aromatic substitution of hydrogen (SNAr) pathways, respectively.
