Synthesis and binding properties of amide-functionalised polyaza macrocycles

Abstract

A series of amide N-functionalised coronands has been prepared based on parent [9]-N₃, [12]-N₃, [12]-N₂O₂, and [12]-N₄ polyazamacrocycles. Complexation with alkali and alkaline earth cations, particularly Li⁺, Na⁺, and Ca²⁺, has been monitored by using ¹³C NMR and IR spectroscopy, fast atom bombardment mass spectrometry, calorimetric, and potentiometric analysis in aqueous and alcoholic media. Particularly strong complexation in water has been observed for Ca²⁺ with 1,4,7,10-tetrakis(N,N-dimethylacetamido)-1,4,7,10-tetra-azacyclododecane, (9)(log K_s= 6.82-[H₂O, 298 K]), and selective Ca²⁺ complexation was observed with 1,7-dioxa-4,10-bis(dimethylethanamido)-4, 10-diazacyclododecane, (7).