Water‐Soluble Sal
<sub>2</sub>
en‐ and Reduced Sal
<sub>2</sub>
en‐Type Ligands: Study of Their Cu
<sup>II</sup>
and Ni
<sup>II</sup>
Complexes in the Solid State and in Solution
作者:Isabel Correia、Agnes Dornyei、Tamás Jakusch、Fernando Avecilla、Tamás Kiss、João Costa Pessoa
DOI:10.1002/ejic.200600030
日期:2006.7
AbstractThe CuII and NiII complexes of the Schiff base pyr2en [N,N′‐ethylenebis(pyridoxyliminato)] and reduced Schiff bases Rpyr2en [N,N′‐ethylenebis(pyridoxylaminato)] and R(SO3–sal)2en (SO3–sal = salicylaldehyde‐5‐sulfonate) were prepared and characterized by elemental analysis, IR, UV/Vis, and EPR spectroscopy. The structure of Ni(pyr2en)·3H2O was determined by single‐crystal X‐ray diffraction. The pyr2en2– ligand is coordinated through two phenolate‐O and imine‐N atoms, in a distorted square‐planar geometry. The complexation of CuII and NiII with Rpyr2en in aqueous solution is studied by pH‐potentiometry, UV/Vis spectroscopy, as well as by EPR spectroscopy for the CuII system, and 1H NMR spectroscopy for the NiII system. Complex formation constants were determined and binding modes proposed. While for the CuII system all complexes present a 1:1 stoichiometry with different protonation states, for the NiII system the 2:1 (L/M) complexes become important in the basic pH range at a higher ligand excess. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)