metal-organic compounds
Bis(1,2-dimethoxyethane)-1κ2O,O′;3κ2O,O′-tetrakis(μ-1,1,1,3,3,3-hexafluoro-2-methylpropan-2-olato)-1:2κ4O:O;2:3κ4O:O-1,3-dilithium-2-magnesium
aInstitut für Allgemeine und Anorganische und Theoretische Chemie, Universität Innsbruck, Innrain 82, A-6020 Innsbruck, Austria, and bLehrstuhl für Makromolekulare Stoffe und Faserchemie, Institut für Polymerchemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
*Correspondence e-mail: michael.buchmeiser@ipoc.uni-stuttgart.de
The title compound, [Li2Mg(C4H3F6O)4(C4H10O2)2], forms as a white crystalline powder by-product of the reaction of lithium 1,1,1,3,3,3-hexafluoro-2-methyl-2-propoxide with Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(O3SCF3)2·2DME (DME is 1,2-dimethoxyethane) contaminated with MgCl2. The of this compound contains half a molecule in the with a twofold rotation axis through the central Mg2+ cation. The four 1,1,1,3,3,3-hexafluoro-2-methylpropan-2-olate ligands serve as bridging ligands connecting the Li+ and Mg2+ cations. The Li+ cation is additionally stabilized by a DME ligand. This results in a distorted tetrahedral around both the Mg2+ and Li+ cations.
Related literature
For general background on the properties and synthesis of Schrock-type catalysts, see: Oskam et al. (1993).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: COLLECT (Nonius, 1998); cell DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL and publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536812032679/zl2496sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812032679/zl2496Isup2.hkl
All reactions were carried out in an MBraun
system (Garching, Germany) using carefully dried and deoxygenated solvents. Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(OTf)2.2DME (1) was prepared according to the literature (Oskam et al., 1993). Briefly, ethereal solutions of 1 (1.21 g, contaminated with MgCl2) and LiOC(CF3)2CH3 (0.62 g, 3.3 mmol) were combined at -36°C and the reaction mixture was allowed to warm to room temperature. Filtration through a pad of Celite and crystallization at -36°C yielded the title complex in 10% yield.All non-hydrogen atoms were refined with anisotropic displacement parameters and hydrogen atoms attached to carbon atoms were placed in calculated positions with C—H distances of 0.97 or 0.98 Å and refined with isotropic displacement parameters 1.2 or 1.5 times higher than the value of their carbon atoms.
The synthesis of molybdenum-based Schrock-type catalysts involves the reaction of the catalyst progenitor, a Mo–trifluoromethanesulfonate compound such as Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(OTf)2.2DME (OTf = CF3SO3-), with a lithium alkoxide (Oskam et al., 1993), e.g. LiOC(CF3)2CH3, to yield the corresponding Schrock catalyst Mo(N-2,6-Me22-C6H3)(CHCMe2Ph)(OC(CF3)2CH3)2. This reaction step requires high-purity educts in which case the target compounds can be prepared in high yields. However, occasionally, lower yields are observed and could not be explained so far. Here we report on the X-ray structure of a trinuclear Li–Mg compound that forms virtually quantitatively in case the progenitor compound Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(OTf)2.2DME is contaminated with MgCl2, which is a by-product of the synthesis of this progenitor.
The structure is shown to be a trinuclear complex containing two Li cations and one central Mg cation. Selected geometry parameters are given in Table 1. The two halves of the title compound are related by a twofold axis, which passes through the central magnesium. The Mg atom is coordinated by four η2-bridging Li–1,1,1,3,3,3-hexafluoro-2-methylpropionate ligands that are themselves coordinated to the two Li ions. The latter have each with one 1,2-dimethoxyethane (DME) ligand a distorted tetrahedral ligand sphere. The same distorted tetrahedral ligand sphere exists for the central Mg cation.
In the
no strong intermolecular hydrogen bonds are present, only F—H distances over 2.47 Å could be observed. Therefore the displacement parameters of the CF3 groups and the DME ligands are comparatively large, showing a higher mobility of these atoms. An attempt to refine all non-hydrogen atoms of DME with a disordering model by splitting of the positions leads to a better R value, but was rejected because of too short C—O bond lengths. The distances between these split positions were only in the range of 0.28 to 0.46 Å.For general background on the properties and synthesis of Schrock-type catalysts, see: Oskam et al. (1993).
Data collection: COLLECT (Nonius, 1998); cell
DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS86 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).Fig. 1. Molecular structure and labeling scheme of the title compound. Ellipsoids are drawn at the 30% probability level. Symmetry code (A): 1 - x, y, 3/2 - z. |
[Li2Mg(C4H3F6O)4(C4H10O2)2] | F(000) = 1896 |
Mr = 942.69 | Dx = 1.584 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 10988 reflections |
a = 23.8629 (4) Å | θ = 1.0–25.0° |
b = 9.5396 (6) Å | µ = 0.20 mm−1 |
c = 18.3700 (7) Å | T = 233 K |
β = 109.041 (2)° | Plate, colourless |
V = 3953.0 (3) Å3 | 0.41 × 0.25 × 0.07 mm |
Z = 4 |
Nonius KappaCCD diffractometer | 2603 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
Graphite monochromator | θmax = 25.0°, θmin = 2.3° |
Detector resolution: 9.1 pixels mm-1 | h = 0→28 |
φ and ω scans | k = −11→11 |
10600 measured reflections | l = −21→20 |
3490 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0561P)2 + 3.6053P] where P = (Fo2 + 2Fc2)/3 |
3490 reflections | (Δ/σ)max < 0.001 |
271 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.32 e Å−3 |
0 constraints |
[Li2Mg(C4H3F6O)4(C4H10O2)2] | V = 3953.0 (3) Å3 |
Mr = 942.69 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 23.8629 (4) Å | µ = 0.20 mm−1 |
b = 9.5396 (6) Å | T = 233 K |
c = 18.3700 (7) Å | 0.41 × 0.25 × 0.07 mm |
β = 109.041 (2)° |
Nonius KappaCCD diffractometer | 2603 reflections with I > 2σ(I) |
10600 measured reflections | Rint = 0.031 |
3490 independent reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.06 | Δρmax = 0.25 e Å−3 |
3490 reflections | Δρmin = −0.32 e Å−3 |
271 parameters |
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 | ||
Mg1 | 0.0000 | 0.21820 (10) | 0.7500 | 0.0304 (2) | |
Li1 | 0.12432 (17) | 0.2031 (5) | 0.8154 (2) | 0.0488 (10) | |
O1 | 0.06054 (6) | 0.31089 (15) | 0.83443 (8) | 0.0376 (4) | |
O2 | 0.06414 (6) | 0.11513 (16) | 0.72966 (8) | 0.0380 (4) | |
O3 | 0.19633 (10) | 0.2846 (3) | 0.80007 (14) | 0.0967 (8) | |
O4 | 0.18689 (8) | 0.1002 (3) | 0.89956 (13) | 0.0788 (6) | |
C1 | 0.06148 (11) | 0.4201 (2) | 0.88423 (13) | 0.0452 (6) | |
C2 | 0.00224 (14) | 0.4955 (3) | 0.86486 (17) | 0.0737 (9) | |
H2A | −0.0060 | 0.5439 | 0.8160 | 0.111* | |
H2B | 0.0038 | 0.5629 | 0.9050 | 0.111* | |
H2C | −0.0289 | 0.4278 | 0.8612 | 0.111* | |
C3 | 0.10945 (15) | 0.5255 (3) | 0.88057 (17) | 0.0667 (8) | |
C4 | 0.07842 (12) | 0.3634 (3) | 0.96686 (13) | 0.0534 (7) | |
C5 | 0.06465 (10) | 0.0184 (3) | 0.67423 (12) | 0.0421 (6) | |
C6 | 0.00260 (11) | −0.0155 (3) | 0.61935 (14) | 0.0542 (7) | |
H6A | 0.0054 | −0.0857 | 0.5825 | 0.081* | |
H6B | −0.0153 | 0.0689 | 0.5922 | 0.081* | |
H6C | −0.0216 | −0.0512 | 0.6486 | 0.081* | |
C7 | 0.10204 (12) | 0.0747 (3) | 0.62675 (15) | 0.0596 (7) | |
C8 | 0.09244 (12) | −0.1182 (3) | 0.71356 (15) | 0.0555 (7) | |
C9 | 0.24947 (14) | 0.2386 (5) | 0.8556 (3) | 0.1029 (13) | |
H9A | 0.2652 | 0.3139 | 0.8929 | 0.124* | |
H9B | 0.2788 | 0.2190 | 0.8300 | 0.124* | |
C10 | 0.24142 (16) | 0.1150 (7) | 0.8958 (3) | 0.1183 (16) | |
H10A | 0.2508 | 0.0326 | 0.8700 | 0.142* | |
H10B | 0.2697 | 0.1175 | 0.9483 | 0.142* | |
C11 | 0.2021 (2) | 0.3924 (5) | 0.7506 (3) | 0.1287 (17) | |
H11A | 0.1634 | 0.4151 | 0.7144 | 0.193* | |
H11B | 0.2280 | 0.3614 | 0.7226 | 0.193* | |
H11C | 0.2189 | 0.4749 | 0.7807 | 0.193* | |
C12 | 0.17925 (17) | −0.0164 (4) | 0.9429 (2) | 0.0917 (11) | |
H12A | 0.1382 | −0.0216 | 0.9409 | 0.138* | |
H12B | 0.2045 | −0.0059 | 0.9960 | 0.138* | |
H12C | 0.1898 | −0.1015 | 0.9216 | 0.138* | |
F1 | 0.10808 (12) | 0.6453 (2) | 0.91690 (13) | 0.1145 (8) | |
F2 | 0.16449 (8) | 0.4746 (2) | 0.91064 (10) | 0.0845 (6) | |
F3 | 0.10296 (9) | 0.55831 (18) | 0.80778 (10) | 0.0865 (6) | |
F4 | 0.12382 (7) | 0.27533 (18) | 0.98428 (8) | 0.0694 (5) | |
F5 | 0.03358 (8) | 0.2936 (2) | 0.97813 (9) | 0.0771 (5) | |
F6 | 0.09337 (9) | 0.4647 (2) | 1.02026 (9) | 0.0849 (6) | |
F7 | 0.08268 (9) | 0.1986 (2) | 0.59720 (12) | 0.0964 (7) | |
F8 | 0.10134 (10) | −0.0077 (3) | 0.56813 (11) | 0.1073 (8) | |
F9 | 0.15870 (7) | 0.0932 (2) | 0.66710 (11) | 0.0895 (6) | |
F10 | 0.05962 (9) | −0.17323 (19) | 0.75248 (12) | 0.0885 (6) | |
F11 | 0.14670 (8) | −0.10129 (19) | 0.76398 (10) | 0.0828 (6) | |
F12 | 0.09778 (8) | −0.21737 (18) | 0.66513 (11) | 0.0857 (6) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Mg1 | 0.0262 (5) | 0.0337 (5) | 0.0298 (5) | 0.000 | 0.0072 (4) | 0.000 |
Li1 | 0.033 (2) | 0.062 (3) | 0.048 (2) | −0.0033 (18) | 0.0095 (17) | −0.0061 (19) |
O1 | 0.0339 (8) | 0.0390 (9) | 0.0359 (8) | −0.0013 (6) | 0.0058 (6) | −0.0057 (6) |
O2 | 0.0297 (8) | 0.0446 (9) | 0.0388 (8) | 0.0019 (6) | 0.0099 (6) | −0.0085 (7) |
O3 | 0.0595 (15) | 0.147 (2) | 0.0865 (16) | −0.0383 (14) | 0.0279 (12) | 0.0027 (15) |
O4 | 0.0418 (12) | 0.0969 (17) | 0.0879 (15) | 0.0052 (10) | 0.0077 (10) | 0.0001 (13) |
C1 | 0.0489 (14) | 0.0404 (13) | 0.0406 (12) | 0.0023 (11) | 0.0066 (10) | −0.0092 (11) |
C2 | 0.073 (2) | 0.075 (2) | 0.0640 (18) | 0.0296 (16) | 0.0095 (15) | −0.0161 (15) |
C3 | 0.089 (2) | 0.0455 (17) | 0.0557 (17) | −0.0132 (15) | 0.0098 (15) | −0.0078 (13) |
C4 | 0.0565 (17) | 0.0617 (17) | 0.0384 (13) | −0.0034 (14) | 0.0103 (11) | −0.0119 (12) |
C5 | 0.0365 (13) | 0.0509 (14) | 0.0392 (12) | 0.0032 (10) | 0.0129 (9) | −0.0094 (11) |
C6 | 0.0432 (15) | 0.0642 (17) | 0.0494 (14) | 0.0004 (12) | 0.0071 (11) | −0.0146 (13) |
C7 | 0.0499 (17) | 0.082 (2) | 0.0506 (15) | 0.0043 (14) | 0.0218 (12) | −0.0077 (15) |
C8 | 0.0495 (16) | 0.0560 (17) | 0.0580 (16) | 0.0131 (12) | 0.0132 (13) | −0.0126 (13) |
C9 | 0.0324 (18) | 0.139 (4) | 0.130 (3) | −0.018 (2) | 0.0162 (19) | −0.029 (3) |
C10 | 0.046 (2) | 0.188 (5) | 0.113 (3) | 0.004 (3) | 0.015 (2) | 0.012 (3) |
C11 | 0.125 (4) | 0.147 (4) | 0.132 (4) | −0.052 (3) | 0.067 (3) | 0.006 (3) |
C12 | 0.092 (3) | 0.098 (3) | 0.074 (2) | 0.017 (2) | 0.0123 (19) | 0.013 (2) |
F1 | 0.169 (2) | 0.0519 (11) | 0.1148 (16) | −0.0323 (13) | 0.0355 (15) | −0.0310 (11) |
F2 | 0.0605 (12) | 0.1003 (14) | 0.0786 (11) | −0.0306 (10) | 0.0034 (9) | 0.0063 (10) |
F3 | 0.1160 (16) | 0.0649 (11) | 0.0704 (11) | −0.0227 (10) | 0.0192 (10) | 0.0165 (9) |
F4 | 0.0675 (11) | 0.0814 (11) | 0.0496 (9) | 0.0126 (9) | 0.0058 (7) | 0.0119 (8) |
F5 | 0.0748 (12) | 0.1057 (14) | 0.0553 (9) | −0.0207 (10) | 0.0273 (8) | −0.0062 (9) |
F6 | 0.1072 (15) | 0.0909 (13) | 0.0485 (9) | −0.0129 (11) | 0.0143 (9) | −0.0317 (9) |
F7 | 0.0931 (14) | 0.1067 (16) | 0.1117 (15) | 0.0178 (12) | 0.0638 (12) | 0.0447 (13) |
F8 | 0.1226 (17) | 0.1462 (19) | 0.0784 (13) | −0.0195 (14) | 0.0674 (13) | −0.0434 (13) |
F9 | 0.0449 (10) | 0.1405 (18) | 0.0897 (13) | −0.0109 (10) | 0.0310 (9) | −0.0069 (12) |
F10 | 0.0994 (14) | 0.0670 (11) | 0.1148 (15) | 0.0272 (10) | 0.0566 (12) | 0.0320 (10) |
F11 | 0.0639 (11) | 0.0816 (12) | 0.0795 (11) | 0.0237 (9) | −0.0085 (9) | −0.0071 (9) |
F12 | 0.0897 (13) | 0.0682 (11) | 0.0926 (13) | 0.0250 (9) | 0.0208 (10) | −0.0300 (10) |
Mg1—O1 | 1.9526 (14) | C4—F4 | 1.325 (3) |
Mg1—O1i | 1.9526 (14) | C4—F5 | 1.333 (3) |
Mg1—O2 | 1.9551 (14) | C4—F6 | 1.340 (3) |
Mg1—O2i | 1.9551 (14) | C5—C6 | 1.530 (3) |
Mg1—Li1 | 2.818 (4) | C5—C8 | 1.532 (4) |
Mg1—Li1i | 2.818 (4) | C5—C7 | 1.534 (4) |
Li1—O1 | 1.961 (4) | C6—H6A | 0.9700 |
Li1—O2 | 1.942 (4) | C6—H6B | 0.9700 |
Li1—O3 | 1.988 (4) | C6—H6C | 0.9700 |
Li1—O4 | 2.019 (5) | C7—F7 | 1.319 (3) |
Mg1—Li1 | 2.818 (4) | C7—F9 | 1.325 (3) |
O1—C1 | 1.382 (3) | C7—F8 | 1.329 (3) |
O2—C5 | 1.377 (3) | C8—F10 | 1.329 (3) |
O3—C11 | 1.409 (5) | C8—F12 | 1.333 (3) |
O3—C9 | 1.413 (5) | C8—F11 | 1.333 (3) |
O4—C10 | 1.333 (4) | C9—C10 | 1.437 (7) |
O4—C12 | 1.414 (4) | C9—H9A | 0.9800 |
C1—C2 | 1.522 (4) | C9—H9B | 0.9800 |
C1—C4 | 1.536 (3) | C10—H10A | 0.9800 |
C1—C3 | 1.541 (4) | C10—H10B | 0.9800 |
C2—H2A | 0.9700 | C11—H11A | 0.9700 |
C2—H2B | 0.9700 | C11—H11B | 0.9700 |
C2—H2C | 0.9700 | C11—H11C | 0.9700 |
C3—F1 | 1.329 (3) | C12—H12A | 0.9700 |
C3—F3 | 1.332 (3) | C12—H12B | 0.9700 |
C3—F2 | 1.339 (4) | C12—H12C | 0.9700 |
O1—Mg1—O1i | 126.14 (10) | F4—C4—F5 | 106.2 (2) |
O1—Mg1—O2 | 87.54 (6) | F4—C4—F6 | 106.2 (2) |
O1i—Mg1—O2 | 119.89 (6) | F5—C4—F6 | 106.4 (2) |
O1—Mg1—O2i | 119.89 (6) | F4—C4—C1 | 113.1 (2) |
O1i—Mg1—O2i | 87.54 (6) | F5—C4—C1 | 111.3 (2) |
O2—Mg1—O2i | 119.61 (10) | F6—C4—C1 | 113.0 (2) |
O1—Mg1—Li1 | 44.06 (9) | O2—C5—C6 | 112.89 (18) |
O1i—Mg1—Li1 | 139.90 (10) | O2—C5—C8 | 109.16 (18) |
O2—Mg1—Li1 | 43.50 (9) | C6—C5—C8 | 107.9 (2) |
O2i—Mg1—Li1 | 132.37 (10) | O2—C5—C7 | 109.4 (2) |
O1—Mg1—Li1i | 139.90 (10) | C6—C5—C7 | 108.5 (2) |
O1i—Mg1—Li1i | 44.06 (9) | C8—C5—C7 | 108.9 (2) |
O2—Mg1—Li1i | 132.37 (10) | C5—C6—H6A | 109.5 |
O2i—Mg1—Li1i | 43.50 (9) | C5—C6—H6B | 109.5 |
O1—Li1—O2 | 87.69 (16) | H6A—C6—H6B | 109.5 |
O1—Li1—O3 | 125.3 (2) | C5—C6—H6C | 109.5 |
O1—Li1—O4 | 122.7 (2) | H6A—C6—H6C | 109.5 |
O2—Li1—O3 | 120.0 (2) | H6B—C6—H6C | 109.5 |
O2—Li1—O4 | 125.3 (2) | F7—C7—F9 | 105.5 (3) |
O3—Li1—O4 | 80.86 (17) | F7—C7—F8 | 106.6 (2) |
Li1—Mg1—Li1i | 174.14 (18) | F9—C7—F8 | 105.8 (2) |
O2—Li1—Mg1 | 43.88 (9) | F7—C7—C5 | 110.9 (2) |
O1—Li1—Mg1 | 43.83 (9) | F9—C7—C5 | 113.9 (2) |
O3—Li1—Mg1 | 139.3 (2) | F8—C7—C5 | 113.4 (2) |
O4—Li1—Mg1 | 139.8 (2) | F10—C8—F12 | 106.3 (2) |
C1—O1—Mg1 | 135.67 (14) | F10—C8—F11 | 106.5 (2) |
C1—O1—Li1 | 131.90 (18) | F12—C8—F11 | 105.5 (2) |
Mg1—O1—Li1 | 92.11 (13) | F10—C8—C5 | 110.5 (2) |
C5—O2—Li1 | 134.95 (17) | F12—C8—C5 | 114.2 (2) |
C5—O2—Mg1 | 132.43 (13) | F11—C8—C5 | 113.4 (2) |
Li1—O2—Mg1 | 92.62 (13) | O3—C9—C10 | 112.7 (3) |
C11—O3—C9 | 116.0 (3) | O3—C9—H9A | 109.0 |
C11—O3—Li1 | 130.4 (3) | C10—C9—H9A | 109.0 |
C9—O3—Li1 | 113.0 (3) | O3—C9—H9B | 109.0 |
C10—O4—C12 | 114.8 (3) | C10—C9—H9B | 109.0 |
C10—O4—Li1 | 113.5 (3) | H9A—C9—H9B | 107.8 |
C12—O4—Li1 | 127.9 (2) | O4—C10—C9 | 114.2 (4) |
O1—C1—C2 | 112.9 (2) | O4—C10—H10A | 108.7 |
O1—C1—C4 | 109.35 (19) | C9—C10—H10A | 108.7 |
C2—C1—C4 | 108.8 (2) | O4—C10—H10B | 108.7 |
O1—C1—C3 | 108.3 (2) | C9—C10—H10B | 108.7 |
C2—C1—C3 | 109.1 (2) | H10A—C10—H10B | 107.6 |
C4—C1—C3 | 108.2 (2) | O3—C11—H11A | 109.5 |
C1—C2—H2A | 109.5 | O3—C11—H11B | 109.5 |
C1—C2—H2B | 109.5 | H11A—C11—H11B | 109.5 |
H2A—C2—H2B | 109.5 | O3—C11—H11C | 109.5 |
C1—C2—H2C | 109.5 | H11A—C11—H11C | 109.5 |
H2A—C2—H2C | 109.5 | H11B—C11—H11C | 109.5 |
H2B—C2—H2C | 109.5 | O4—C12—H12A | 109.5 |
F1—C3—F3 | 106.7 (2) | O4—C12—H12B | 109.5 |
F1—C3—F2 | 106.6 (2) | H12A—C12—H12B | 109.5 |
F3—C3—F2 | 106.1 (3) | O4—C12—H12C | 109.5 |
F1—C3—C1 | 113.5 (3) | H12A—C12—H12C | 109.5 |
F3—C3—C1 | 110.6 (2) | H12B—C12—H12C | 109.5 |
F2—C3—C1 | 112.8 (2) | ||
O1—Mg1—Li1—O2 | −177.8 (2) | O2—Li1—O4—C12 | −47.5 (4) |
O1i—Mg1—Li1—O2 | −82.68 (18) | O1—Li1—O4—C12 | 65.9 (4) |
O2i—Mg1—Li1—O2 | 90.60 (17) | O3—Li1—O4—C12 | −167.8 (3) |
O1i—Mg1—Li1—O1 | 95.15 (18) | Mg1—Li1—O4—C12 | 10.5 (5) |
O2—Mg1—Li1—O1 | 177.8 (2) | Mg1—O1—C1—C2 | −6.4 (3) |
O2i—Mg1—Li1—O1 | −91.57 (15) | Li1—O1—C1—C2 | 165.2 (2) |
O1—Mg1—Li1—O3 | −93.8 (3) | Mg1—O1—C1—C4 | 114.8 (2) |
O1i—Mg1—Li1—O3 | 1.3 (4) | Li1—O1—C1—C4 | −73.6 (3) |
O2—Mg1—Li1—O3 | 84.0 (3) | Mg1—O1—C1—C3 | −127.4 (2) |
O2i—Mg1—Li1—O3 | 174.6 (2) | Li1—O1—C1—C3 | 44.2 (3) |
O1—Mg1—Li1—O4 | 88.7 (3) | O1—C1—C3—F1 | 170.0 (2) |
O1i—Mg1—Li1—O4 | −176.1 (2) | C2—C1—C3—F1 | 46.8 (3) |
O2—Mg1—Li1—O4 | −93.5 (3) | C4—C1—C3—F1 | −71.5 (3) |
O2i—Mg1—Li1—O4 | −2.9 (4) | O1—C1—C3—F3 | 50.1 (3) |
O1i—Mg1—O1—C1 | 46.36 (19) | C2—C1—C3—F3 | −73.1 (3) |
O2—Mg1—O1—C1 | 172.3 (2) | C4—C1—C3—F3 | 168.6 (2) |
O2i—Mg1—O1—C1 | −64.7 (2) | O1—C1—C3—F2 | −68.5 (3) |
Li1—Mg1—O1—C1 | 173.8 (3) | C2—C1—C3—F2 | 168.2 (2) |
Li1i—Mg1—O1—C1 | −12.7 (3) | C4—C1—C3—F2 | 50.0 (3) |
O1i—Mg1—O1—Li1 | −127.40 (14) | O1—C1—C4—F4 | 45.1 (3) |
O2—Mg1—O1—Li1 | −1.49 (14) | C2—C1—C4—F4 | 168.8 (2) |
O2i—Mg1—O1—Li1 | 121.59 (14) | C3—C1—C4—F4 | −72.8 (3) |
Li1i—Mg1—O1—Li1 | 173.5 (2) | O1—C1—C4—F5 | −74.5 (3) |
O2—Li1—O1—C1 | −172.63 (19) | C2—C1—C4—F5 | 49.2 (3) |
O3—Li1—O1—C1 | −46.9 (4) | C3—C1—C4—F5 | 167.7 (2) |
O4—Li1—O1—C1 | 56.0 (4) | O1—C1—C4—F6 | 165.8 (2) |
Mg1—Li1—O1—C1 | −174.1 (2) | C2—C1—C4—F6 | −70.5 (3) |
O2—Li1—O1—Mg1 | 1.51 (14) | C3—C1—C4—F6 | 48.0 (3) |
O3—Li1—O1—Mg1 | 127.2 (2) | Li1—O2—C5—C6 | 179.6 (2) |
O4—Li1—O1—Mg1 | −129.9 (2) | Mg1—O2—C5—C6 | −1.2 (3) |
O1—Li1—O2—C5 | 177.9 (2) | Li1—O2—C5—C8 | 59.6 (3) |
O3—Li1—O2—C5 | 47.8 (4) | Mg1—O2—C5—C8 | −121.24 (19) |
O4—Li1—O2—C5 | −52.7 (4) | Li1—O2—C5—C7 | −59.5 (3) |
Mg1—Li1—O2—C5 | 179.4 (3) | Mg1—O2—C5—C7 | 119.70 (19) |
O1—Li1—O2—Mg1 | −1.50 (14) | O2—C5—C7—F7 | −55.3 (3) |
O3—Li1—O2—Mg1 | −131.6 (2) | C6—C5—C7—F7 | 68.2 (3) |
O4—Li1—O2—Mg1 | 127.9 (2) | C8—C5—C7—F7 | −174.6 (2) |
O1—Mg1—O2—C5 | −177.90 (19) | O2—C5—C7—F9 | 63.5 (3) |
O1i—Mg1—O2—C5 | −46.9 (2) | C6—C5—C7—F9 | −172.9 (2) |
O2i—Mg1—O2—C5 | 58.78 (18) | C8—C5—C7—F9 | −55.7 (3) |
Li1—Mg1—O2—C5 | −179.4 (3) | O2—C5—C7—F8 | −175.3 (2) |
Li1i—Mg1—O2—C5 | 6.4 (2) | C6—C5—C7—F8 | −51.7 (3) |
O1—Mg1—O2—Li1 | 1.51 (14) | C8—C5—C7—F8 | 65.5 (3) |
O1i—Mg1—O2—Li1 | 132.53 (14) | O2—C5—C8—F10 | 63.4 (3) |
O2i—Mg1—O2—Li1 | −121.82 (14) | C6—C5—C8—F10 | −59.7 (3) |
Li1i—Mg1—O2—Li1 | −174.16 (18) | C7—C5—C8—F10 | −177.2 (2) |
O2—Li1—O3—C11 | 60.1 (5) | O2—C5—C8—F12 | −176.9 (2) |
O1—Li1—O3—C11 | −50.4 (5) | C6—C5—C8—F12 | 60.0 (3) |
O4—Li1—O3—C11 | −174.3 (4) | C7—C5—C8—F12 | −57.5 (3) |
Mg1—Li1—O3—C11 | 7.4 (5) | O2—C5—C8—F11 | −56.0 (3) |
O2—Li1—O3—C9 | −129.6 (3) | C6—C5—C8—F11 | −179.1 (2) |
O1—Li1—O3—C9 | 119.9 (3) | C7—C5—C8—F11 | 63.4 (3) |
O4—Li1—O3—C9 | −4.0 (3) | C11—O3—C9—C10 | −171.0 (4) |
Mg1—Li1—O3—C9 | 177.7 (3) | Li1—O3—C9—C10 | 17.2 (5) |
O2—Li1—O4—C10 | 109.4 (4) | C12—O4—C10—C9 | −176.4 (4) |
O1—Li1—O4—C10 | −137.2 (3) | Li1—O4—C10—C9 | 23.6 (5) |
O3—Li1—O4—C10 | −10.9 (3) | O3—C9—C10—O4 | −27.0 (6) |
Mg1—Li1—O4—C10 | 167.4 (4) |
Symmetry code: (i) −x, y, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | [Li2Mg(C4H3F6O)4(C4H10O2)2] |
Mr | 942.69 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 233 |
a, b, c (Å) | 23.8629 (4), 9.5396 (6), 18.3700 (7) |
β (°) | 109.041 (2) |
V (Å3) | 3953.0 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.20 |
Crystal size (mm) | 0.41 × 0.25 × 0.07 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10600, 3490, 2603 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.127, 1.06 |
No. of reflections | 3490 |
No. of parameters | 271 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.25, −0.32 |
Computer programs: COLLECT (Nonius, 1998), DENZO-SMN (Otwinowski & Minor, 1997), DENZO/SCALEPACK (Otwinowski & Minor, 1997), SHELXS86 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).
Mg1—O1 | 1.9526 (14) | Li1—O3 | 1.988 (4) |
Mg1—O2 | 1.9551 (14) | Li1—O4 | 2.019 (5) |
Li1—O1 | 1.961 (4) | Mg1—Li1 | 2.818 (4) |
Li1—O2 | 1.942 (4) | ||
O1—Mg1—O1i | 126.14 (10) | O1—Li1—O4 | 122.7 (2) |
O1—Mg1—O2 | 87.54 (6) | O2—Li1—O3 | 120.0 (2) |
O1—Mg1—O2i | 119.89 (6) | O2—Li1—O4 | 125.3 (2) |
O2—Mg1—O2i | 119.61 (10) | O3—Li1—O4 | 80.86 (17) |
O1—Li1—O2 | 87.69 (16) | Li1—Mg1—Li1i | 174.14 (18) |
O1—Li1—O3 | 125.3 (2) |
Symmetry code: (i) −x, y, −z+3/2. |
Acknowledgements
Financial support provided by the DFG (BU 2174/8-1) is gratefully acknowledged. The authors thank S. P. Westrip and the IUCr for the development of publCIF.
References
Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Oskam, J. H., Fox, H. H., Yap, K. B., McConville, D. H., O'Dell, R., Lichtenstein, B. J. & Schrock, R. R. (1993). J. Organomet. Chem. 459, 185–197. CrossRef CAS Web of Science Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The synthesis of molybdenum-based Schrock-type catalysts involves the reaction of the catalyst progenitor, a Mo–trifluoromethanesulfonate compound such as Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(OTf)2.2DME (OTf = CF3SO3-), with a lithium alkoxide (Oskam et al., 1993), e.g. LiOC(CF3)2CH3, to yield the corresponding Schrock catalyst Mo(N-2,6-Me22-C6H3)(CHCMe2Ph)(OC(CF3)2CH3)2. This reaction step requires high-purity educts in which case the target compounds can be prepared in high yields. However, occasionally, lower yields are observed and could not be explained so far. Here we report on the X-ray structure of a trinuclear Li–Mg compound that forms virtually quantitatively in case the progenitor compound Mo(N-2,6-Me2—C6H3)(CHCMe2Ph)(OTf)2.2DME is contaminated with MgCl2, which is a by-product of the synthesis of this progenitor.
The structure is shown to be a trinuclear complex containing two Li cations and one central Mg cation. Selected geometry parameters are given in Table 1. The two halves of the title compound are related by a twofold axis, which passes through the central magnesium. The Mg atom is coordinated by four η2-bridging Li–1,1,1,3,3,3-hexafluoro-2-methylpropionate ligands that are themselves coordinated to the two Li ions. The latter have each with one 1,2-dimethoxyethane (DME) ligand a distorted tetrahedral ligand sphere. The same distorted tetrahedral ligand sphere exists for the central Mg cation.
In the crystal structure no strong intermolecular hydrogen bonds are present, only F—H distances over 2.47 Å could be observed. Therefore the displacement parameters of the CF3 groups and the DME ligands are comparatively large, showing a higher mobility of these atoms. An attempt to refine all non-hydrogen atoms of DME with a disordering model by splitting of the positions leads to a better R value, but was rejected because of too short C—O bond lengths. The distances between these split positions were only in the range of 0.28 to 0.46 Å.