Tetrakis(tert-butyl 3-oxobutanoato)­zirconium(IV)

The structure of the title compound, [Zr(C₈H₁₃O₃)₄], an MOCVD precursor, has been determined. The zirconium coordination geometry is dodecahedral and the chelate rings are significantly non-planar. The Zr atom lies on a axis, so the asymmetric unit contains only one ligand.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.047
• wR factor = 0.102
• Data-to-parameter ratio = 19.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



RINTA_01  Alert C The value of Rint is greater than 0.10
          Rint given   0.122


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

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S1. Comment

The structure of the title zirconium complex, (I), an MOCVD precursor, has been determined. The molecular fourfold inversion symmetry (4) is retained in the crystal structure, with the Zr atom occupying a special position. The coordination geometry is dodecahedral (Hoard & Silverton, 1963) and not a square antiprism, as in tetrakis(acetylacetonato)zirconium(IV) (Clegg, 1987; Silverton & Hoard, 1963). The ligand has tert-butoxy as a substituent on one side and methyl on the other, as in the Fe complex, also an MOCVD precursor, reported by us previously (Urs et al., 2000). The ligand bite O···O distance is 2.703 (2) Å. The six-membered chelate ring is significantly non-planar, the angle between the Zr1/O1/O2 and C1/C2/C3 planes being 3.8 (2)° (Nardelli, 1995). The packing is essentially by van der Waals interactions. There are two intramolecular short contacts of the C—H···O type involving the tert-butyl atoms C6 and C7, and the chelate ring atom O2, with C···O distances of 2.999 (3) and 2.906 (4) Å, and angles at H of 114.2 (2) and 116.6 (2)°, respectively.

S2. Experimental

The title compound was synthesized by refluxing zirconium n-propoxide with tert-butyl 3-oxobutanoate in dry benzene, under flowing dry nitrogen. 10 mmol (2.31 g) of zirconium n-propoxide was placed in a three-necked round-bottomed flask connected to the dry nitrogen gas line. 40 mmol (6.12 g) of tert-butyl 3-oxobutanoate was added, using a pressure equalizer fitted to one of the necks. A reflux condenser fitted with calcium chloride guard tube was fitted to the third neck, to ensure that the system was moisture-free. The reaction mixture was refluxed for 3 h-. The propanol-benzene mixture and the excess solvent were removed by distillation. The residue (4.42 g, 85%) was recrystallized from hot n-hexane.

S3. Refinement

H atoms were located in the difference Fourier maps, then positioned geometrically and allowed to ride on their respective parent atoms. [Please check this added text]

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. H atoms have been omitted for clarity and only the atoms of the asymmetric unit are labelled.
	Fig. 2. Packing of the molecules, viewed down the c axis.

tetrakis(tert-butyl-3-oxobutanoato)zirconium(IV)

Crystal data

[Zr(C8H13O3)4]	Dx = 1.282 Mg m^−3
Mr = 719.96	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I41/a	Cell parameters from 19762 reflections
Hall symbol: -I 4 a d	θ = 2.2–27.5°
a = 18.569 (4) Å	µ = 0.35 mm^−1
c = 10.818 (3) Å	T = 293 K
V = 3730.2 (16) Å^3	Prism, colourless
Z = 4	0.19 × 0.13 × 0.05 mm
F(000) = 1520

Data collection

Bruker SMART CCD area-detector diffractometer	2111 independent reflections
Radiation source: fine-focus sealed tube	1491 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.122
ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −23→24
Tmin = 0.84, Tmax = 0.98	k = −23→22
19762 measured reflections	l = −14→13

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.102	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0535P)^2] where P = (Fo^2 + 2Fc^2)/3
2111 reflections	(Δ/σ)max < 0.001
106 parameters	Δρmax = 0.44 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Zr1	0.5	0.25	0.875	0.04925 (18)
C2	0.64288 (12)	0.23444 (13)	1.1037 (2)	0.0560 (6)
H2	0.6805	0.2299	1.16	0.067*
O1	0.58487 (8)	0.18326 (8)	0.93303 (14)	0.0582 (4)
C3	0.63292 (12)	0.18194 (12)	1.0182 (2)	0.0539 (6)
C4	0.67992 (16)	0.11612 (14)	1.0194 (3)	0.0793 (8)
H4A	0.6511	0.0745	1.0373	0.119*
H4B	0.7163	0.1214	1.0817	0.119*
H4C	0.7023	0.1105	0.9401	0.119*
O2	0.54445 (9)	0.30685 (8)	1.04535 (13)	0.0574 (4)
O3	0.61859 (8)	0.34273 (8)	1.19704 (14)	0.0586 (4)
C1	0.59793 (13)	0.29600 (12)	1.11038 (18)	0.0502 (5)
C5	0.57846 (14)	0.40956 (13)	1.2219 (2)	0.0609 (6)
C6	0.50571 (16)	0.39087 (17)	1.2726 (3)	0.0855 (9)
H6A	0.4763	0.3714	1.2078	0.128*
H6B	0.4834	0.4334	1.3053	0.128*
H6C	0.5109	0.3558	1.3372	0.128*
C7	0.5760 (2)	0.45555 (17)	1.1094 (3)	0.1054 (12)
H7A	0.6237	0.4612	1.077	0.158*
H7B	0.5567	0.5019	1.1304	0.158*
H7C	0.5459	0.4332	1.0483	0.158*
C8	0.62509 (18)	0.44386 (16)	1.3217 (3)	0.0931 (10)
H8A	0.6275	0.4124	1.392	0.14*
H8B	0.6045	0.4891	1.346	0.14*
H8C	0.6727	0.4517	1.2899	0.14*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zr1	0.0524 (2)	0.0524 (2)	0.0430 (2)	0	0	0
C2	0.0499 (13)	0.0525 (14)	0.0655 (14)	0.0019 (11)	−0.0056 (11)	−0.0013 (11)
O1	0.0620 (10)	0.0578 (10)	0.0549 (9)	0.0082 (8)	−0.0017 (8)	−0.0054 (7)
C3	0.0484 (13)	0.0510 (14)	0.0624 (13)	−0.0007 (11)	0.0061 (11)	0.0024 (11)
C4	0.0780 (19)	0.0610 (16)	0.099 (2)	0.0158 (14)	−0.0093 (16)	−0.0101 (15)
O2	0.0651 (10)	0.0569 (10)	0.0502 (9)	0.0101 (8)	−0.0069 (8)	−0.0049 (7)
O3	0.0588 (10)	0.0527 (9)	0.0642 (10)	0.0028 (8)	−0.0073 (8)	−0.0113 (7)
C1	0.0553 (14)	0.0507 (13)	0.0445 (11)	−0.0048 (10)	0.0035 (10)	0.0022 (9)
C5	0.0659 (15)	0.0498 (14)	0.0669 (14)	0.0021 (12)	−0.0010 (12)	−0.0100 (11)
C6	0.0723 (19)	0.093 (2)	0.091 (2)	0.0030 (16)	0.0092 (15)	−0.0260 (17)
C7	0.161 (4)	0.0560 (18)	0.099 (2)	0.012 (2)	0.004 (2)	0.0110 (16)
C8	0.091 (2)	0.074 (2)	0.115 (2)	0.0034 (17)	−0.0229 (19)	−0.0367 (18)

Geometric parameters (Å, º)

Zr1—O1^i	2.1008 (16)	C2—C1	1.417 (3)
Zr1—O1^ii	2.1008 (16)	O1—C3	1.283 (3)
Zr1—O1^iii	2.1008 (16)	C3—C4	1.502 (3)
Zr1—O1	2.1008 (16)	O2—C1	1.234 (3)
Zr1—O2	2.2786 (16)	O3—C1	1.334 (3)
Zr1—O2^ii	2.2786 (15)	O3—C5	1.472 (3)
Zr1—O2^iii	2.2786 (15)	C5—C7	1.487 (4)
Zr1—O2^i	2.2786 (15)	C5—C6	1.499 (4)
C2—C3	1.357 (3)	C5—C8	1.523 (4)
O1^i—Zr1—O1^ii	95.12 (2)	O1^ii—Zr1—O2^i	143.41 (6)
O1^i—Zr1—O1^iii	95.12 (2)	O1^iii—Zr1—O2^i	71.36 (6)
O1^ii—Zr1—O1^iii	145.23 (8)	O1—Zr1—O2^i	75.92 (6)
O1^i—Zr1—O1	145.23 (8)	O2—Zr1—O2^i	72.05 (8)
O1^ii—Zr1—O1	95.12 (2)	O2^ii—Zr1—O2^i	130.85 (5)
O1^iii—Zr1—O1	95.12 (2)	O2^iii—Zr1—O2^i	130.85 (5)
O1^i—Zr1—O2	75.92 (6)	C3—C2—C1	122.3 (2)
O1^ii—Zr1—O2	71.36 (6)	C3—O1—Zr1	138.39 (15)
O1^iii—Zr1—O2	143.41 (6)	O1—C3—C2	124.8 (2)
O1—Zr1—O2	76.11 (6)	O1—C3—C4	115.2 (2)
O1^i—Zr1—O2^ii	71.36 (6)	C2—C3—C4	120.0 (2)
O1^ii—Zr1—O2^ii	76.11 (6)	C1—O2—Zr1	132.62 (14)
O1^iii—Zr1—O2^ii	75.92 (6)	C1—O3—C5	122.09 (18)
O1—Zr1—O2^ii	143.41 (6)	O2—C1—O3	121.7 (2)
O2—Zr1—O2^ii	130.85 (5)	O2—C1—C2	125.2 (2)
O1^i—Zr1—O2^iii	143.41 (6)	O3—C1—C2	113.0 (2)
O1^ii—Zr1—O2^iii	75.92 (6)	O3—C5—C7	110.5 (2)
O1^iii—Zr1—O2^iii	76.11 (6)	O3—C5—C6	109.1 (2)
O1—Zr1—O2^iii	71.36 (6)	C7—C5—C6	113.8 (3)
O2—Zr1—O2^iii	130.85 (5)	O3—C5—C8	101.20 (19)
O2^ii—Zr1—O2^iii	72.05 (8)	C7—C5—C8	110.9 (3)
O1^i—Zr1—O2^i	76.11 (6)	C6—C5—C8	110.5 (2)
O1^i—Zr1—O1—C3	−38.7 (2)	O1—Zr1—O2—C1	7.6 (2)
O1^ii—Zr1—O1—C3	67.96 (19)	O2^ii—Zr1—O2—C1	−144.0 (2)
O1^iii—Zr1—O1—C3	−145.3 (2)	O2^iii—Zr1—O2—C1	−41.96 (19)
O2—Zr1—O1—C3	−1.4 (2)	O2^i—Zr1—O2—C1	87.0 (2)
O2^ii—Zr1—O1—C3	141.5 (2)	Zr1—O2—C1—O3	170.86 (13)
O2^iii—Zr1—O1—C3	141.2 (2)	Zr1—O2—C1—C2	−9.9 (3)
O2^i—Zr1—O1—C3	−76.0 (2)	C5—O3—C1—O2	0.9 (3)
Zr1—O1—C3—C2	−2.6 (4)	C5—O3—C1—C2	−178.42 (19)
Zr1—O1—C3—C4	177.14 (17)	C3—C2—C1—O2	3.6 (4)
C1—C2—C3—O1	2.7 (4)	C3—C2—C1—O3	−177.1 (2)
C1—C2—C3—C4	−177.0 (2)	C1—O3—C5—C7	−60.0 (3)
O1^i—Zr1—O2—C1	166.7 (2)	C1—O3—C5—C6	65.9 (3)
O1^ii—Zr1—O2—C1	−92.8 (2)	C1—O3—C5—C8	−177.6 (2)
O1^iii—Zr1—O2—C1	87.3 (2)

Symmetry codes: (i) −x+1, −y+1/2, z; (ii) −y+3/4, x−1/4, −z+7/4; (iii) y+1/4, −x+3/4, −z+7/4.