Introduction to Topic of the Special Issue "Quantum-Chemical Modeling and Design of Chelate and Macrocyclic Metal Complexes 2.0" from Guest Editor.

The concept of "macrocyclic compounds" combines very different classes of chemicals that contain nine or more atoms in the macrocycle; macroheterocyclic compounds, the macrocycle of which contains at least one heteroatom, are also distinguished among them [...].