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Varying the metal/metal ratio in related Cu–Ca complexes
Ist Teil von
Polyhedron, 2007-09, Vol.26 (15), p.4209-4215
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2007
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Copper complexes derived from compartmental Schiff base ligands react with calcium ions to yield trinuclear Cu–Ca–Cu entities while dinuclear Cu–Ca complexes can also be isolated with use of auxiliary ligands such as diketones; the trinuclear Cu–Ca–Cu entities do not allow to synthesize the corresponding trinuclear Cu–Ln–Cu complexes.
We demonstrate with the help of structural determinations and spectroscopic data that the nuclearity of Cu–Ca complexes derived from compartmental Schiff base ligands does not depend on the ionic radius of calcium. The main factors governing these reactions are the different affinities of the calcium ions for the anionic species present in solution: the tetradentate O
2O
2 coordination site of the ligand and the nitrato ions. Because these affinities do vary upon going from calcium to lanthanide ions, it is not possible to use the template effect of the trinuclear Cu–Ca–Cu complexes in order to prepare the corresponding Cu–Ln–Cu complexes.