Acta Cryst. (2009). E65, m809 [ doi:10.1107/S1600536809023186 ]
The title compound, [Zn(C9H11)2] or Mes2Zn (Mes = mesityl = 2,4,6-trimethylphenyl), crystallizes with a quarter of a molecule in the asymmetric unit. The ZnII atom is in a strictly linear environment with a Zn-C bond length of 1.951 (5) Å. Due to the imposed 2/m symmetry, both aromatic rings are coplanar. One of the methyl groups is disordered over two equally occupied positions.
All manipulations were performed in an atmosphere of argon using standard Schlenk techniques. THF and toluene were dried (Na/benzophenone) and distilled prior to use. Mes2Zn was prepared according to a literature procedure (Seidel & Bürger, 1981). Recrystallization of Mes2Zn from toluene at +4%C led to the formation of single crystals of the title compound.
All hydrogen atoms were set to idealized positions and were refined with 1.2 times (1.5 for methyl groups) the isotropic displacement parameter of the corresponding carbon atom. One of the methyl groups is disordered over two equally occupied positions. The structure contains solvent accessible voids. But the final difference peak of 1.33 e/A3 is on a special position and could not be related to a solvent molecule.
Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./bt2971fig1thm.gif)
| Fig. 1. Molecular structure of Mes2Zn, showing 40% probability displacement ellipsoides and the atom numbering scheme. |
| [Zn(C9H11)2] | Dx = 1.192 Mg m−3 |
| Mr = 303.73 | Mo Kα radiation, λ = 0.71073 Å |
| Tetragonal, P42/ncm | Cell parameters from 10286 reflections |
| Hall symbol: -P 4ac 2ac | θ = 3.2–27.5° |
| a = 18.3059 (9) Å | µ = 1.44 mm−1 |
| c = 5.0494 (4) Å | T = 183 K |
| V = 1692.08 (18) Å3 | Octaeder, colourless |
| Z = 4 | 0.05 × 0.05 × 0.04 mm |
| F(000) = 640 |
| Nonius KappaCCD diffractometer | 685 reflections with I > 2σ(I) |
| Radiation source: fine-focus sealed tube | Rint = 0.046 |
| graphite | θmax = 27.5°, θmin = 3.2° |
| φ and ω scans | h = −22→23 |
| 10286 measured reflections | k = −23→23 |
| 1016 independent reflections | l = −6→5 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.071 | H-atom parameters constrained |
| wR(F2) = 0.270 | w = 1/[σ2(Fo2) + (0.1807P)2 + 0.5133P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.13 | (Δ/σ)max < 0.001 |
| 1016 reflections | Δρmax = 1.33 e Å−3 |
| 53 parameters | Δρmin = −0.60 e Å−3 |
| 0 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.041 (11) |
| [Zn(C9H11)2] | Z = 4 |
| Mr = 303.73 | Mo Kα radiation |
| Tetragonal, P42/ncm | µ = 1.44 mm−1 |
| a = 18.3059 (9) Å | T = 183 K |
| c = 5.0494 (4) Å | 0.05 × 0.05 × 0.04 mm |
| V = 1692.08 (18) Å3 |
| Nonius KappaCCD diffractometer | 685 reflections with I > 2σ(I) |
| 10286 measured reflections | Rint = 0.046 |
| 1016 independent reflections | θmax = 27.5° |
| R[F2 > 2σ(F2)] = 0.071 | H-atom parameters constrained |
| wR(F2) = 0.270 | Δρmax = 1.33 e Å−3 |
| S = 1.13 | Δρmin = −0.60 e Å−3 |
| 1016 reflections | Absolute structure: ? |
| 53 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | Occ. (<1) | |
| Zn1 | 0.0000 | 0.5000 | 0.0000 | 0.0388 (6) | |
| C1 | −0.0524 (2) | 0.5524 (2) | −0.2778 (9) | 0.0397 (13) | |
| C2 | −0.1176 (2) | 0.5250 (2) | −0.3816 (7) | 0.0413 (11) | |
| C3 | −0.1542 (2) | 0.5623 (2) | −0.5831 (8) | 0.0424 (11) | |
| H3A | −0.1987 | 0.5431 | −0.6500 | 0.051* | |
| C4 | −0.1268 (2) | 0.6268 (2) | −0.6875 (9) | 0.0432 (14) | |
| C5 | −0.1687 (2) | 0.6687 (2) | −0.8986 (11) | 0.0455 (14) | |
| H5A | −0.1418 | 0.7132 | −0.9452 | 0.068* | 0.50 |
| H5B | −0.2170 | 0.6820 | −0.8302 | 0.068* | 0.50 |
| H5C | −0.1743 | 0.6381 | −1.0563 | 0.068* | 0.50 |
| C6 | −0.1516 (2) | 0.4566 (2) | −0.2699 (8) | 0.0503 (12) | |
| H6A | −0.1933 | 0.4422 | −0.3799 | 0.075* | |
| H6B | −0.1683 | 0.4659 | −0.0886 | 0.075* | |
| H6C | −0.1153 | 0.4172 | −0.2687 | 0.075* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Zn1 | 0.0385 (7) | 0.0385 (7) | 0.0394 (9) | 0.0034 (3) | −0.0015 (2) | 0.0015 (2) |
| C1 | 0.0435 (19) | 0.0435 (19) | 0.032 (2) | 0.008 (2) | 0.0036 (14) | −0.0036 (14) |
| C2 | 0.043 (2) | 0.044 (2) | 0.038 (2) | 0.0059 (17) | 0.0021 (16) | −0.0033 (16) |
| C3 | 0.046 (2) | 0.045 (2) | 0.0353 (19) | 0.0052 (16) | 0.0002 (16) | −0.0052 (17) |
| C4 | 0.051 (2) | 0.051 (2) | 0.028 (2) | 0.010 (3) | 0.0028 (14) | −0.0028 (14) |
| C5 | 0.054 (2) | 0.054 (2) | 0.029 (3) | 0.005 (3) | −0.0019 (16) | 0.0019 (16) |
| C6 | 0.052 (3) | 0.045 (2) | 0.054 (2) | −0.0005 (18) | −0.0011 (19) | 0.0024 (19) |
| Zn1—C1 | 1.951 (5) | C4—C3ii | 1.386 (5) |
| Zn1—C1i | 1.951 (5) | C4—C5 | 1.522 (7) |
| C1—C2ii | 1.396 (5) | C5—H5A | 0.9800 |
| C1—C2 | 1.396 (5) | C5—H5B | 0.9800 |
| C2—C3 | 1.397 (6) | C5—H5C | 0.9800 |
| C2—C6 | 1.509 (6) | C6—H6A | 0.9800 |
| C3—C4 | 1.386 (5) | C6—H6B | 0.9800 |
| C3—H3A | 0.9500 | C6—H6C | 0.9800 |
| C1—Zn1—C1i | 179.999 (1) | C4—C5—H5A | 109.5 |
| C2ii—C1—C2 | 118.1 (5) | C4—C5—H5B | 109.5 |
| C2ii—C1—Zn1 | 120.9 (2) | H5A—C5—H5B | 109.5 |
| C2—C1—Zn1 | 120.9 (2) | C4—C5—H5C | 109.5 |
| C1—C2—C3 | 120.6 (4) | H5A—C5—H5C | 109.5 |
| C1—C2—C6 | 120.7 (4) | H5B—C5—H5C | 109.5 |
| C3—C2—C6 | 118.7 (3) | C2—C6—H6A | 109.5 |
| C4—C3—C2 | 121.3 (4) | C2—C6—H6B | 109.5 |
| C4—C3—H3A | 119.4 | H6A—C6—H6B | 109.5 |
| C2—C3—H3A | 119.4 | C2—C6—H6C | 109.5 |
| C3ii—C4—C3 | 118.1 (5) | H6A—C6—H6C | 109.5 |
| C3ii—C4—C5 | 120.9 (2) | H6B—C6—H6C | 109.5 |
| C3—C4—C5 | 120.9 (2) |
| Symmetry codes: (i) −x, −y+1, −z; (ii) −y+1/2, −x+1/2, z. |
We thank the Deutsche Forschungsgemeinschaft (DFG, Bonn–Band Godesberg, Germany) for generous financial support. We also acknowledge the funding of the Fonds der Chemischen Indunstrie (Frankfurt/Main, Germany). In addition, SK is very grateful to the Verband der Chemischen Industrie (VCI/FCI) for a PhD grant.
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After the first synthesis of dimesitylzinc by Seidel & Bürger (1981), its structure was determined more than 20 years later (Cole et al., 2003). Here we present another modification of this diarylzinc compound.
Whereas dialkylzinc is monomeric diphenylzinc crystallizes as a loose and unsymmetric dimer (Markies et al. (1990)). A planar molecule with a strictly two coordinated zinc centre is observed for bis(2,4,6-trimethylphenyl)zinc (dimesitylzinc) by Cole et al. (2003). Other substitution patterns of the arene ring also lead to monomeric, but not strictly linear molecules in the solid state. Sun et al. (1998) published the structure of bis(pentafluorophenyl)zinc and Brooker et al. (1992) reported the structure of bis[2,4,6-tris(rifluoromethyl)phenyl]zinc with a C—Zn—C bond angle of 170°. A The C—Zn—C angle decreases with increasing steric chain and a value of 165.9° was found in bis[2,4,6-tri(tert -butylphenyl]zinc by Westerhausen et al. (2005).