Enthalpy of formation of copper(II) complexes with 14-membered tetra-aza macrocycles

Abstract

Calorimetric studies show that the 14-membered macrocycle (1) incorporates copper(II) more exothermically than its less symmetric isomer (2), owing to stronger in-plane Cu–N interactions; introduction of a pyridine ring in the macrocyclic framework (3) further reduces the heat of complexation.