Abstract
The research investigations aiming at taking advantage of the chemical and structural consequences of ligand macrocyclization are reviewed with regard to the three features as follows: (1) Tetraazacycloalkane complexes which take up carbon dioxide as ROCO2 − or R2NCO2 −; (2) Correlation between axial and inplane coordination bond lengths in tetragonal six-coordinate complexes of trans-MX2N4-type (MyCo3+, Ni2+, and Zn2+)-X-ray structural and ab initio MO studies and (3) Stabilization of high oxidation states of metal ions and its application to chemistry of one-dimensional halogen-bridged M2+-M4+ mixed valence complexes.