Synthesis of Hetero-multinuclear Metal Complexes by Site-Selective Redox Switching and Transmetalation on a Homo-multinuclear Complex.

Hetero-multinuclear metal complexes are a promising class of compounds applicable to photoluminescence, magnetism, and catalysis. In this work, we have developed a synthetic method for hetero-tetranuclear metal complexes by combining advantages of site-selective redox switching and transmetalation. First, a homo-tetranuclear CoII4 complex was converted to a mixed-valence CoIIICoII3 complex by site-selective oxidation, which was then transmetalated from CoII to NiII to form a heterometallic CoIIINiII3 complex. Finally, a CoIINiII3 complex was synthesized by metal-selective reduction on the CoIII site. The basic structural frameworks of the main products in the whole process starting from the CoII4 complex are isostructural. Notably, the CoIINiII3 complex was not accessible by direct mixing of ligand, CoII, and NiII. This method would provide an alternative strategy for highly selective synthesis of hetero-multinuclear metal complexes.