Synthesis and properties of some novel ferrocene macrocyclic dioxopolyamines

A series of novel ferrocene macrocyclic dioxopolyamines (1–4) bearing an iminodiacetamide fragment in their framework were designed and synthesized, and two such new ligands (2 and 4) and some of their complexes are reported. The coordination behavior and electrochemical properties of these compounds were systematically examined by cyclic voltammetry (CV) and electronic absorption spectroscopy. Host–guest complexation stoichiometries (1:1) have been confirmed by fast atom bombardment mass spectroscopy (FAB MS) and UV–vis titration of cobalt ion and ligands 3 and 4. Additionally the stability constants for the equilibrium of cobalt ion and ligands 3 and 4 have been evaluated. The coordination of the ligands with transition metal ions (Cu2+, Ni2+ and Co2+) causes anodic shifts of the ferrocene redox couple to various extents. The uncommon oxidation state of nickel(III) and copper(III) can be selectively stabilized by tetra-azamacrocycle 1 and penta-azamacrocycles, 3 and 4, respectively.