Heterotri- and Heteropentanuclear Copper(I)–Ferrocenyl Complexes Assembled through a “Click” Strategy: A Structural, Electrochemical, and Spectroelectrochemical Investigation

Abstract

The ferrocene moiety with its well-defined redox behavior and its substitution potential is ideally suited for the assembly of multinuclear complexes. Utilizing the “click” strategy, we present here mono- and disubstituted pyridyl–triazolyl–ferrocene units. The “pyridyl–triazolyl” chelating pocket is then used to chelate to copper(I) centers that additionally contain dppf [dppf = 1,1′-(diphenylphosphino)ferrocene], which has an additional ferrocene moiety. This strategy delivers a heterotrinuclear (Fe–Cu–Fe) and a heteropentanuclear (Fe–Cu–Fe–Cu–Fe) complex. All complexes were characterized by1H and13C NMR spectroscopy and by mass spectrometry, and the heteropentanuclear complex was characterized by single-crystal X-ray diffraction. Electrochemistry and UV/Vis/NIR spectroelectrochemistry were used to investigate the redox properties of the complexes and to determine the site of electron transfer. The results presented here show the potential of “click”-derived ligands in generating heteromultinuclear assemblies and the potential of ferrocene to function as a rigid, redox-active unit in these assemblies.