Armed-azacrown ethers having dual binding sites in a side arm: Complexing abilities and crystal structure of two alkali-metal complexes

✍ Scribed by Yoichi Habata; Tomomi Saeki; Sadatoshi Akabori; Xian X. Zhang; Jerald S. Bradshaw

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2001
• Tongue: English
• Weight: 115 KB
• Volume: 38
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570380137

✦ Synopsis

Abstract

New armed‐monoaza‐12‐crown‐4 and armed‐monoaza‐15‐crown‐5 ethers having dual phenolic OH and pyridine nitrogen binding sites in a side arm were prepared by the Mannich reaction of N‐methoxymethyl‐monoazacrown ethers with 3‐hydroxypyridine. Complexation studies of these new hydroxypyridine‐armed ligands were carried out by liquid membrane transport, ^1^H nmr titration experiments, thermodynamic values (log K, ΔH and TΔS), and X‐ray crystallography of two alkali‐metal complexes. These results indicate that the oxygen atom of the phenolic OH group and pyridine nitrogen atom of the side arm are involved in complexation under basic and neutral conditions, respectively.