New Macrocyclic Ligands. IV. Dibenzo-Substituted Rings Incorporating Five Donor Atoms. X-Ray Structures of an N₄O-Donor Macrocycle, Its Protonated Form, and Its Complex With Barium Perchlorate

Abstract

The syntheses and characterization of four dibenzo-substituted macrocycles incorporating N_5-, N₄O-or N₄S-donor sets are reported. The new systems extend the range of related (potentially pentadentate ) macrocyclic systems of this general structure reported previously. For the 17-membered macrocycle incorporating an N₄O-donor set, X-ray structure determinations of the free ligand and its salt of type [LH]ClO₄ confirm the structure of this compound predicted from physical measurements. The diperchloratobarium complex of this macrocycle is shown to have the barium nine-coordinate; the coordination sphere is composed of the N₄O-donors of the macrocycle and four oxygen atoms derived from a monodentate as well as a bidentate perchlorate group and an ethanol molecule.