Tetrabenzylzirconium

Tetrabenzylzirconium is an organozirconium compound with the formula Zr₄. The molecule features diamagnetic Zr bonded to four benzyl ligands. It is an orange air- and photo-sensitive solid, which is soluble in hydrocarbon solvents. The compound is a precursor to catalysts for the polymerization of olefins.

Structure, synthesis, reactions

X-ray crystallography demonstrates that the benzyl ligands are highly flexible: one polymorph features four η²-ligands, whereas another has two η¹- and two η²-benzyl ligands.
The compound is prepared by combining benzylmagnesium chloride and zirconium tetrachloride in diethyl ether.
Tetrabenzylzirconium readily undergoes protonolysis, e.g. with hydrogen chloride: