Reactions of Copper(II) Chloride in Solution: Facile Formation of Tetranuclear Copper Clusters and Other Complexes That Are Relevant in Catalytic Redox Processes
Article first published online: 28 FEB 2013
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chemistry - A European Journal
Volume 19, Issue 17, pages 5342–5351, April 22, 2013
How to Cite
Löw, S., Becker, J., Würtele, C., Miska, A., Kleeberg, C., Behrens, U., Walter, O. and Schindler, S. (2013), Reactions of Copper(II) Chloride in Solution: Facile Formation of Tetranuclear Copper Clusters and Other Complexes That Are Relevant in Catalytic Redox Processes. Chem. Eur. J., 19: 5342–5351. doi: 10.1002/chem.201203848
- Issue published online: 12 APR 2013
- Article first published online: 28 FEB 2013
- Manuscript Received: 29 OCT 2013
- Stiftung Stipendienfonds der Chemischen Industrie e.V.
- cluster compounds;
- homogeneous catalysis;
Mixing CuCl2⋅2 H2O with benzylamine in alcoholic solutions led to an extremely colorful chemistry caused by the formation of a large number of different complexes. Many of these different species could be structurally characterized. These include relatively simple compounds such as [Cu(L1)4Cl2] (L1=benzylamine) and (HL1)2[CuCl4]. Most interestingly is the easy formation of two cluster complexes, one based on two cluster units Cu4OCl6(L1)4 connected through one [Cu(L1)2Cl2] complex and one based on a cubane-type cluster ([Cu4O4](C11H14)4Cl4). Both clusters proved to be highly reactive in a series of oxidation reactions of organic substrates by using air or peroxides as oxidants. Furthermore, it was possible to isolate and structurally characterize ([Cu(L1)Cl]3 and [Cu(benz2mpa)2]CuCl2 (benz2mpa=benzyl-(2-benzylimino-1-methyl-propylidene)-amine), two copper(I) complexes that formed in solution, demonstrating the high redox activity of the cluster systems. In addition, it was possible to solve the molecular structures of the compounds Cu4OCl6(MeOH)4, [Cu(MeOH)2Cl2], [Cu(aniline)2Cl2], and an organic side product (HC13H19NOCl). In fact all determined structures are of a known type but the chemical relation between these compounds could be explained for the first time. The paper describes these different compounds and their chemical equilibria. Some of these complexes seem to be relevant in catalytic oxidation reactions and their reactivity is discussed in more detail.