Ni(^4-tBustb)₃: A Robust 16-Electron Ni(0) Olefin Complex for Catalysis

Abstract

Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4-tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4-tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4-CF3stb)3 in a variety of relevant Ni-catalyzed transformations.