22356-89-4Relevant articles and documents
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Molday,R.S.,Kallen,R.G.
, p. 6739 - 6745 (1972)
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Effect of Monoelectronic Oxidation of an Unsymmetrical Phenoxido-Hydroxido Bridged Dicopper(II) Complex
Thibon-Pourret, Aurore,Gennarini, Federica,David, Rolf,Isaac, James A.,Lopez, Isidoro,Gellon, Gisèle,Molton, Florian,Wojcik, Laurianne,Philouze, Christian,Flot, David,Le Mest, Yves,Réglier, Marius,Le Poul, Nicolas,Jamet, Hélène,Belle, Catherine
, p. 12364 - 12375 (2018/09/27)
A (μ-hydroxido, μ-phenoxido)CuIICuII complex 1 has been synthesized using an unsymmetrical ligand bearing an N,N-bis(2-pyridyl)methylamine (BPA) moiety coordinating one copper and a dianionic bis-amide moiety coordinating the other copper(II) ion. Electrochemical mono-oxidation of the complex in DMF occurs reversibly at 213 K at E1/2 = 0.12 V vs Fc+/Fc through a metal-centered process. The resulting species (complex 1+) is only stable at low temperature and has been spectroscopically characterized by UV-vis-NIR cryo-spectroelectrochemical and EPR methods. DFT and TD-DFT calculations, consistent with experimental data, support the formation of a CuIICuIII phenoxido-hydroxido complex. Low-temperature chemical oxidation of 1 by NOSbF6 yields a tetranuclear complex 2(SbF6)(NO2) which displays two binuclear CuIICuII subunits. The X-ray crystal structure of 2(SbF6)(NO2) evidences that the nitrogen of the terminal amide group is protonated and the coordination of the amide occurs via the O atom. The bis-amide moiety appears to be a non-innocent proton acceptor along the redox process. Alternatively, protonation of complex 1 leads to the complex 2(ClO4)2, as evidenced by X-ray crystallography, cyclic voltammetry, and 1H NMR.
Readily accessible chiral at nitrogen cage structures
Rowley, Julian H.,Yau, Sze Chak,Kariuki, Benson M.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
, p. 2198 - 2205 (2013/05/09)
The reaction of glycine-N-methyl amide with paraformaldehyde in the presence of ytterbium triflate (1 mol%) leads to a novel cage structure 6 which is chiral at nitrogen. Single crystal X-ray analysis and DFT calculations suggest this cage structure is rigid and adopts a single low energy conformation. Use of single enantiomer α-amino amides results in two diastereomeric tertiary amines that differ in their absolute configuration at nitrogen. These diastereoisomers interconvert under acidic conditions but are configurationally stable under basic conditions and can be readily separated by either crystallisation or column chromatography. By reacting racemic chiral α-amino amides a third diastereomeric cage can also be isolated through this reaction protocol. Preparation of mixed cages by reacting two different α-amino amides is also possible allowing for greater structural diversity in the products to be attained. Preliminary mechanistic studies show that all three methylene units in the cage structure are labile and can be replaced under acidic reaction conditions. The Royal Society of Chemistry 2013.