N-bridged heterocycles. Part 5. αω-Bis-(2-oxobenzimidazolinyl)alkanes and -ethers as selective ligands for group-1 and -2 metals

Abstract

A series of the title compounds (10), (12), and (13) and several analogues were synthesised from the readily available 1-isopropenylbenzimidazolin-2-one. Various substituents were attached to the unsubstituted nitrogen atoms of the benzimidazolinone moieties and the series of products obtained were tested for their complexing ability with group-1 and -2 metal-salts. The isolation of crystalline complexes, the solubilisation of the salts in chloroform by the ligand, the i.r. carbonyl absorption shift, and the ion-transport ability of the ligand were examined as an index of complexation. Selective complexation, particularly for calcium, was noted in several cases.