Step-by-step explanation:
The macrocyclic effect in coordination chemistry refers to the enhanced stability of metal complexes that have a macrocyclic ligand. A macrocyclic ligand is a ligand that forms a ring around the metal ion, forming a macrocyclic complex. This structure increases the enthalpy of the complex, making it more thermodynamically stable. In other words, the macrocyclic effect increases the stability of a metal complex by making the ligand more difficult to remove. This effect is especially important in biological systems, where macrocyclic ligands play a key role in many enzymatic reactions.