A new oxo-azamacrocyclic ligand: 13,27-dimethyl-6,20-dioxa-3,9,17,23-tetraaza-tricyclo[23.3.1.1 11,15]triaconta-1(29),11, 13,15(30),25,27-hexaene-29,30-diol, and a dinuclear copper(II) complex: syntheses, characterization and binding ability

Abstract

A new dinucleating tetraaza-dioxo-diphenol macrocyclic ligand: 13,27-dimethyl-6,20-dioxa-3,9,17,23-tetraaza-tricyclo[23.3.1.1 11,15]triaconta-1(29),11, 13,15(30),25,27-hexaene-29,30-diol (L or BDOD) was synthesized and characterized. This ligand serves as the N 4O 4 2− motif for cation ions. The binding constants of divalent copper were determined using direct potentiometric titration. The logarithm formation constants of copper complexes are: log[CuL]=22.62 and log[Cu 2L]=15.74. This macrocyclic ligand acts as the host to accommodate two copper ions at same time. The dinuclear copper complex were determined to be a central symmetric molecule with the formation of Cu 2O 2 bridge. Bond lengths of CuO(phenol) is 1.952 Å, which is shorter than that of CuO(2) 2.368 Å consistent with the expected Jahn–Teller distortion. CuN(av.) is 1.998 Å. The coordination polyhedron of each copper ion is a slightly distorted square pyramid.