Tetrabenzylzirconium

Tetrabenzylzirconium is an organozirconium compound with the formula Zr(CH₂C₆H₅)₄. The molecule features diamagnetic Zr(IV) 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.^{[2] [3]}

Tetrabenzylzirconium

Identifiers
CAS Number	24356-01-2
3D model (JSmol)	Interactive image
ChemSpider	10254475
PubChem CID	520121
CompTox Dashboard (EPA)	DTXSID80334254
InChI InChI=1S/4C7H7.Zr/c4*1-7-5-3-2-4-6-7;/h4*2-6H,1H2;/q4*-1;+4 Key: QSLMQGXOMLSFAW-UHFFFAOYSA-N
SMILES [CH2-]C1=CC=CC=C1.[CH2-]C1=CC=CC=C1.[CH2-]C1=CC=CC=C1.[CH2-]C1=CC=CC=C1.[Zr+4]
Properties
Chemical formula	C28H28Zr
Molar mass	455.756 g·mol−1
Appearance	orange solid
Density	1.34-1.39 g/cm3[1]
Melting point	133–134 °C (271–273 °F; 406–407 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Structure, synthesis, reactions

Structure of tetrabenzylzirconium as determined by X-ray crystallography, with H atoms omitted for clarity.^[1]

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.^[1]

The compound is prepared by combining benzylmagnesium chloride and zirconium tetrachloride in diethyl ether.^[4]

Tetrabenzylzirconium readily undergoes protonolysis, e.g. with hydrogen chloride:

Zr(CH₂C₆H₅)₄ + HCl → Zr(CH₂C₆H₅)₃Cl + CH₃C₆H₅

References

1. Rong, Yi; Al-Harbi, Ahmed; Parkin, Gerard (2012). "Highly Variable Zr–CH₂–Ph Bond Angles in Tetrabenzylzirconium: Analysis of Benzyl Ligand Coordination Modes". Organometallics. 31 (23): 8208–8217. doi:10.1021/om300820b.
2. Tshuva, Edit Y.; Goldberg, Israel; Kol, Moshe (2000). "Isospecific Living Polymerization of 1-Hexene by a Readily Available Nonmetallocene C₂-Symmetrical Zirconium Catalyst". Journal of the American Chemical Society. 122 (43): 10706–10707. doi:10.1021/ja001219g.
3. Zucchini, U.; Albizzati, E.; Giannini, U. (1971). "Synthesis and Properties of Some Titanium and Zirconium Benzyl Derivatives". Journal of Organometallic Chemistry. 26 (3): 357–372. doi:10.1016/S0022-328X(00)82618-2.
4. Mashima, Kazushi; Tsurugi, Hatato (2013). "Tetrabenzylzirconium". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn01555. ISBN 978-0471936237.