Synthesis and Characterization of Some Metal Complexes with New Nitrogen–Oxygen Donor Macrocyclic Ligands – X-ray Crystal Structures of a 26-Membered Reduced Monoprotonated Macrocycle and a 20-Membered Pendant-Arm Schiff-Base Macrocyclic Cadmium(II) Complex

Abstract

New series of macrocyclic Schiff-base lanthanide(III), yttrium(III), and cadmium(II) complexes, [M(1)]Xn (X = NO, M = Y, Ln = La–Yb except Pm and Dy; X = ClO, M = Cd, La, Ce, Pr, Sm, Gd, or Er) and [M(3)]Xn (X = NO, M = Dy; X = ClO, M = Er and Cd), have been prepared by cyclocondensation of O1,O7-bis(2-formylphenyl)-1,4,7-trioxaheptane with O1,O7-bis(2-aninyl)-1,4,7-trioxaheptane (1) or tris(2-aminoethyl)amine (3) in the presence of the appropriate metal salt as a template agent. The Schiff-base macrocycles 1 and 3 are also formed in the absence of a metal ion. Treatment of 1 with NaBH4 in methanol gives the diamine macrocycle 2. The reactions of LnIII, CdII, and YIII ions with 2 have also been investigated. The crystal structures of the monoprotonated ligand 2 and of the complex [Cd(3)](ClO4)2 have been determined by X-ray diffraction analysis.