The formation of complexes between aza-derivatives of crown ethers and primary alkylammonium salts. Part 2. Diaza-derivatives of metacyclophanes

Abstract

The diazametacyclophanes (6) and the derivatives (15) have been synthesised and the formation of complexes between these host macrocycles and guest primary alkylammonium salts in CD₂Cl₂ has been examined using n.m.r. line-shape methods. In general the strengths of the complexes for any particular guest are in the order (6b) > (6c)(6a). A detailed examination of the complexes of (6b) shows that binding is affected adversely by steric interactions between guest and host, by the presence of certain additional functional groups in the guest cation, and by the lack of lipophilic shielding of the guest NH₃ group. Complex formation by the derivatives (15) is affected by the side chains containing functional groups, and in some cases the binding energy is significantly increased relative to complex formation by the diazametacyclophane (6b).