Rethinking Molecular Frameworks while Broadening the Scope of Amido Group-IV Metal Catalysts

Much of the current interest in organometallic chemistry is linked to the academic and industrial quest for novel types of efficient and selective homogeneous catalysts. Improving the catalyst's performance implies a precise control of the metal coordination sphere, commonly accomplished by a fine tuning of the steric and electronic properties of the ancillary ligands. A recent work from our group has unveiled an original and temperature controlled prototropic rearrangement occurring on selected amido Group IV polymerization catalysts stabilized by (potentially) dianionic tridentate {C-,N,N-} amido-pyridinate ligands (Scheme 1, left). This aspect adds additional levels of complexity to the interpretation of their catalytic activity as as well as to the identification of the truly catalytic active species. Rethinking molecular frameworks while maintaining the same donor atom set, led us towards more robust and tailored "pincer-type" Group IV complexes. ZrIV and HfIV pincer-type complexes exhibit enhanced and to some extent unique catalytic activity in aminoalkene hydroamination reactions compared to previously reported Group IV metal-based catalyst systems. A detailed complexes synthesis and catalytic performance in hydroamination reaction will be discussed.