Synthesis, Structure and Binding Properties of Nickel and Copper [14]Cyclidene Complexes with Appended Aza Crown Ethers

✍ Scribed by Bohdan Korybut-Daszkiewicz; Joanna Taraszewska; Katarzyna Zięba; Anna Makal; Krzysztof Woźniak

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 377 KB
• Volume: 2004
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200300955

✦ Synopsis

Abstract

Copper(II) and nickel(II) cyclidenes linked with one or two 15‐azacrown‐5 ethers (3Ni, 4Ni and 4Cu) as well as similar model morpholine‐substituted derivatives (2Cu, 2Ni) have been synthesized and characterized using ESI mass‐spectrometry, X‐ray diffraction, spectroscopic methods and elemental analysis. Cyclic voltammetry of the copper complexes exhibits two reversible redox couples Cu^II/III^ and Cu^II/I^, whereas the nickel complexes show reversible Ni^II/III^ and irreversible Ni^II/I^ redox processes. Cyclic and differential pulse voltammetry have been used to study interactions of metal cations and amino acids with the above complexes. Na^+^ and Li^+^ interact weakly with the 3Ni complex. In the presence of Mg^2+^, the ligand isomerizes from aldehyde to enolate ion, which interacts strongly with Mg^2+^. The presence of lysine caused a more pronounced shift of the Cu^II/III^ potential in 4Cu than did leucyne. This suggests that there are interactions between the NH~3~^+^ group and the crown ether moiety and between the carboxylic group and the Cu^III^ center of the former guest. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)