From metal complexes to metallosupramolecular polymers via polycondensation: Synthesis, structure and electrochromic properties of Co(III)- and Fe(III)-based metallosupramolecular polymers with aromatic azo ligands

Co(III)- and Fe(III)-based metallosupramolecular polymers with aromatic azo ligands were synthesized via polycondensation of the diamino-substituted metal complexes with aromatic dialdehydes. Three different amino-substituted Co(III)-complexes were prepared through Csingle bondN fusion reaction of [Co(pap)3](ClO4)2 with 1,4-phenylenediamine. All Co(III)- and Fe(III)-monomers and the metallosupramolecular polymers and a Co(III)-dimer were characterized by NMR, MS and UV–vis spectroscopy. Both the Co(III)- and Fe(III)-based metallosupramolecular polymers were electrochemically active and exhibited reversible electrochromism. The color of the Co(III)-based metallosupramolecular polymer could be changed upon application of an appropriate potential and regenerated upon reversal of the potential.