Dichlorido-1κCl,3κCl-hexa­kis­[1,1,2,2,3,3(η5)-cyclo­penta­dien­yl]di-μ2-oxido-1:2κ2 O:O;2:3κ2 O:O-trizirconium(IV)

Bradley M Kraft; William W Brennessel

doi:10.1107/S1600536812024968

. 2012 Jun 13;68(Pt 7):m893. doi: 10.1107/S1600536812024968

Dichlorido-1κCl,3κCl-hexakis[1,1,2,2,3,3(η⁵)-cyclopentadienyl]di-μ₂-oxido-1:2κ² O:O;2:3κ² O:O-trizirconium(IV)

Bradley M Kraft ^a,^*, William W Brennessel ^b

PMCID: PMC3393167 PMID: 22807735

Abstract

The title compound, [Zr₃(C₅H₅)₆Cl₂O₂], exists as discrete molecules possessing a series of three Cp₂Zr units (Cp is cyclopentadienyl) bridged by oxide ligands and end-capped by chloride ligands. The Cp planes in the central and terminal zirconocene units form dihedral angles of 53.3 (2) and 53.5 (2)°, respectively. The two Zr—O—Zr bridge angles are nearly linear and form a planar Zr₃O₂ core. The molecule bears C2 symmetry with the central Zr atom lying on a crystallographic twofold axis.

Related literature

For closely related Zr molecules with only one oxo bridge, see: Reid et al. (1965 ▶); Clarke & Drew (1974 ▶); Kuz’mina et al. (1988 ▶); Nieger et al. (1999 ▶); Spletstoser et al. (2007 ▶). For cyclic trimeric oxozirconocenes, see: Arnold et al. (2011 ▶); Boutonnet et al. (1995 ▶); Mikhailova et al. (1993 ▶). For similar structures with terminal Zr–Cl bonds, see: Corey et al. (1995 ▶); Reddy & Petersen (1989 ▶). For the Hf analog, but with methyl-substituted cyclopentadienyl rings, see: Wisniewska et al. (2008 ▶).

Experimental

Crystal data

[Zr₃(C₅H₅)₆Cl₂O₂]
M _r = 767.10
Orthorhombic,
a = 7.8809 (4) Å
b = 18.0518 (10) Å
c = 20.1883 (11) Å
V = 2872.1 (3) Å³
Z = 4
Mo Kα radiation
μ = 1.28 mm⁻¹
T = 223 K
0.20 × 0.18 × 0.04 mm

Data collection

Bruker SMART APEXII CCD Platform diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008b ▶) T _min = 0.784, T _max = 0.951
34715 measured reflections
4032 independent reflections
2569 reflections with I > 2σ(I)
R _int = 0.099

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.100
S = 1.01
4032 reflections
168 parameters
H-atom parameters constrained
Δρ_max = 0.52 e Å⁻³
Δρ_min = −0.48 e Å⁻³

Data collection: APEX2 (Bruker, 2011 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008a ▶); molecular graphics: SHELXTL (Sheldrick, 2008a ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812024968/pk2418sup1.cif

e-68-0m893-sup1.cif^{(34.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812024968/pk2418Isup2.hkl

e-68-0m893-Isup2.hkl^{(197.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Zr1—O1	1.921 (3)
Zr1—Cl1	2.4857 (12)
Zr2—O1	1.980 (3)
Zr2—O1ⁱ	1.980 (2)

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O1—Zr1—Cl1	97.23 (8)
O1—Zr2—O1ⁱ	102.43 (15)
Zr1—O1—Zr2	171.43 (15)

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

The geometry around each Zr in the title compound is pseudotetrahedral with the center of each Cp ligand taken as a single coordination site. The dihedral angle between the Cp rings in the central zirconocene unit is 53.3 (2)° and that between the Cp rings in the terminal zirconocene units is 53.5 (2)°, similar to those in related structures (Mikhailova et al., 1993, Spletstoser et al., 2007). As with many cyclic trimeric oxozirconocenes (Arnold et al., 2011; Boutonnet et al., 1995; Mikhailova et al., 1993), the three Zr atoms and bridging O atoms are also planar in this open structure with the µ₂-O ligands deviating above and below the plane each by 0.144 (3) Å. The nearly linear Zr–O–Zr angles (171.43 (15)°) indicate double-bonding character with each neighboring Zr atom. The O–Zr–O angle is 102.43 (15)°, which is wider than that found in cyclic trinuclear oxozirconocenes (Arnold et al., 2011; Mikhailova et al., 1993) and wider than that in the methyl-substituted cyclopentadienyl hafnium analog (Wisniewska et al., 2008). The Zr–O distances of 1.921 (3) and 1.980 (2) Å are comparable with those of other µ₂-oxo Zr complexes (Kuz'mina et al., 1988, Spletstoser et al., 2007). The Zr–Cl distances of 2.4857 (12) Å are typical (Corey et al., 1995; Reddy & Petersen, 1989).

Experimental

The title compound was isolated as pale yellow needles upon hydrolysis of Cp₂Zr(Cl)(L) [L = 4-methyl-2,6-bis(2,6-diisopropylphenylimino)phenoxy] by adventitious water in THF/pentane.