Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270111023134/em3041sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270111023134/em3041Isup2.hkl |
CCDC reference: 838137
To a stirred suspension of NaCH2SiMe3 (0.11 g, 1.0 mmol) in hexane (15 ml) was added Mg(CH2SiMe3)2 (0.20 g, 1.0 mmol), and the resulting white suspension was stirred at room temperature for 1 h. The volume of solvent was reduced by approximately half under reduced pressure. Benzene (3 ml) was then introduced and the mixture was gently heated. A CaCl2 drying tube was fitted and the reaction mixture was exposed to air through this for 1 h before being resealed and stirred overnight. The solvent was removed in vacuo and hexane (5 ml) was added with gentle heating. After being allowed to cool slowly to room temperature, the resulting colourless solution afforded a crop of colourless crystals of (I) (yield 0.03 g, 15%). Spectroscopic analysis: 1H NMR (400.03 MHz, 298 K, C6D6, δ, p.p.m.): -2.12 (4H, s, SiCH2), -0.04 [9H, s, Si(CH3)3], -0.35 [18H, s, OSi(CH3)3], 3.43 (2H, s, OCH2); 13C {1H} NMR (100.62 MHz, 298 K, C6D6, δ, p.p.m.): -6.00 (MCH2), -2.61 [OCH2Si(CH3)3], 4.65 [MCH2Si(CH3)3], 55.37 (OCH2).
The H atoms of the CH2 groups were found through difference synthesis and refined isotropically. Methyl group H-atom positions were found by allowing the torsion angle about the Si—C bond to refine but with an idealized geometry, with C—H = 0.98 Å and Uiso(H) = 1.5Ueq(C).
Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO (Oxford Diffraction, 2010); data reduction: CrysAlis PRO (Oxford Diffraction, 2010); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
[Na2Mg2(C4H11OSi)2(C4H11Si)4] | F(000) = 712 |
Mr = 649.91 | Dx = 1.030 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 7568 reflections |
a = 9.8057 (3) Å | θ = 2.8–30.3° |
b = 18.1602 (5) Å | µ = 0.27 mm−1 |
c = 11.8234 (3) Å | T = 123 K |
β = 95.482 (3)° | Block, colourless |
V = 2095.80 (10) Å3 | 0.23 × 0.18 × 0.15 mm |
Z = 2 |
Oxford Gemini S diffractometer | 5052 independent reflections |
Radiation source: fine-focus sealed tube | 3663 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.046 |
Detector resolution: 16.0268 pixels mm-1 | θmax = 28.0°, θmin = 2.8° |
ω scans | h = −12→12 |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010) | k = −23→23 |
Tmin = 0.804, Tmax = 1.000 | l = −15→15 |
17871 measured 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)] = 0.039 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.100 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.96 | w = 1/[σ2(Fo2) + (0.0566P)2] where P = (Fo2 + 2Fc2)/3 |
5052 reflections | (Δ/σ)max < 0.001 |
196 parameters | Δρmax = 0.46 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
[Na2Mg2(C4H11OSi)2(C4H11Si)4] | V = 2095.80 (10) Å3 |
Mr = 649.91 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.8057 (3) Å | µ = 0.27 mm−1 |
b = 18.1602 (5) Å | T = 123 K |
c = 11.8234 (3) Å | 0.23 × 0.18 × 0.15 mm |
β = 95.482 (3)° |
Oxford Gemini S diffractometer | 5052 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010) | 3663 reflections with I > 2σ(I) |
Tmin = 0.804, Tmax = 1.000 | Rint = 0.046 |
17871 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.100 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.96 | Δρmax = 0.46 e Å−3 |
5052 reflections | Δρmin = −0.28 e Å−3 |
196 parameters |
Experimental. Version 1.171.33.66 (release 28-04-2010 CrysAlis171 .NET) (compiled Apr 28 2010,14:27:37) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
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 | −0.00426 (6) | 0.05122 (3) | −0.09983 (4) | 0.01719 (13) | |
Na1 | 0.00110 (7) | 0.11740 (3) | 0.14529 (5) | 0.02509 (17) | |
Si1 | 0.34964 (5) | 0.11136 (3) | 0.12990 (4) | 0.02460 (13) | |
Si2 | −0.22055 (5) | 0.19736 (3) | −0.17790 (4) | 0.02400 (13) | |
Si3 | −0.18934 (6) | −0.05907 (3) | 0.33618 (4) | 0.02845 (13) | |
O1 | 0.11632 (11) | 0.03426 (5) | 0.04690 (9) | 0.0169 (2) | |
C1 | 0.26296 (17) | 0.03189 (9) | 0.05188 (14) | 0.0193 (3) | |
C2 | 0.3087 (2) | 0.11026 (13) | 0.28116 (17) | 0.0492 (6) | |
H2A | 0.3420 | 0.0643 | 0.3173 | 0.074* | |
H2B | 0.2093 | 0.1138 | 0.2837 | 0.074* | |
H2C | 0.3533 | 0.1522 | 0.3217 | 0.074* | |
C3 | 0.5377 (2) | 0.10166 (12) | 0.12316 (18) | 0.0381 (5) | |
H3A | 0.5579 | 0.1014 | 0.0436 | 0.057* | |
H3B | 0.5691 | 0.0554 | 0.1595 | 0.057* | |
H3C | 0.5851 | 0.1431 | 0.1629 | 0.057* | |
C4 | 0.2891 (2) | 0.19933 (10) | 0.0612 (2) | 0.0446 (6) | |
H4A | 0.3337 | 0.2409 | 0.1027 | 0.067* | |
H4B | 0.1896 | 0.2033 | 0.0624 | 0.067* | |
H4C | 0.3122 | 0.2001 | −0.0177 | 0.067* | |
C5 | −0.11609 (19) | 0.15148 (9) | −0.06267 (14) | 0.0215 (4) | |
C6 | −0.1122 (2) | 0.26732 (10) | −0.24626 (16) | 0.0311 (4) | |
H6A | −0.0900 | 0.3080 | −0.1932 | 0.047* | |
H6B | −0.1630 | 0.2864 | −0.3155 | 0.047* | |
H6C | −0.0274 | 0.2440 | −0.2655 | 0.047* | |
C7 | −0.3707 (2) | 0.24875 (12) | −0.1311 (2) | 0.0486 (6) | |
H7A | −0.4260 | 0.2155 | −0.0887 | 0.073* | |
H7B | −0.4267 | 0.2677 | −0.1978 | 0.073* | |
H7C | −0.3380 | 0.2899 | −0.0821 | 0.073* | |
C8 | −0.2894 (2) | 0.13150 (11) | −0.29098 (18) | 0.0433 (5) | |
H8A | −0.2135 | 0.1039 | −0.3188 | 0.065* | |
H8B | −0.3377 | 0.1589 | −0.3540 | 0.065* | |
H8C | −0.3530 | 0.0972 | −0.2594 | 0.065* | |
C9 | −0.09097 (19) | −0.00313 (10) | 0.24275 (14) | 0.0235 (4) | |
C10 | −0.3040 (3) | −0.00285 (15) | 0.42114 (19) | 0.0592 (7) | |
H10A | −0.2480 | 0.0285 | 0.4747 | 0.089* | |
H10B | −0.3601 | −0.0358 | 0.4633 | 0.089* | |
H10C | −0.3639 | 0.0281 | 0.3698 | 0.089* | |
C11 | −0.3025 (3) | −0.12490 (13) | 0.2498 (2) | 0.0577 (7) | |
H11A | −0.3607 | −0.0977 | 0.1922 | 0.087* | |
H11B | −0.3602 | −0.1514 | 0.2995 | 0.087* | |
H11C | −0.2460 | −0.1602 | 0.2124 | 0.087* | |
C12 | −0.0731 (2) | −0.11256 (10) | 0.44100 (16) | 0.0362 (5) | |
H12A | −0.0129 | −0.1440 | 0.4002 | 0.054* | |
H12B | −0.1281 | −0.1433 | 0.4874 | 0.054* | |
H12C | −0.0175 | −0.0784 | 0.4902 | 0.054* | |
H1A | 0.2966 (18) | −0.0126 (9) | 0.0897 (14) | 0.020 (4)* | |
H1B | 0.2951 (18) | 0.0301 (9) | −0.0295 (15) | 0.025 (5)* | |
H5A | −0.181 (2) | 0.1348 (10) | −0.0094 (18) | 0.040 (6)* | |
H5B | −0.065 (2) | 0.1868 (11) | −0.0281 (17) | 0.041 (6)* | |
H9A | −0.022 (2) | 0.0234 (9) | 0.2927 (15) | 0.028 (5)* | |
H9B | −0.160 (2) | 0.0311 (10) | 0.2058 (16) | 0.032 (5)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Mg1 | 0.0198 (3) | 0.0154 (3) | 0.0169 (3) | −0.0005 (2) | 0.0042 (2) | 0.0013 (2) |
Na1 | 0.0311 (4) | 0.0207 (3) | 0.0243 (3) | 0.0029 (3) | 0.0073 (3) | −0.0031 (3) |
Si1 | 0.0194 (3) | 0.0288 (3) | 0.0262 (3) | −0.0044 (2) | 0.0053 (2) | −0.0080 (2) |
Si2 | 0.0227 (3) | 0.0233 (2) | 0.0263 (2) | 0.0017 (2) | 0.0043 (2) | 0.00898 (19) |
Si3 | 0.0277 (3) | 0.0373 (3) | 0.0212 (2) | −0.0048 (2) | 0.0070 (2) | 0.0047 (2) |
O1 | 0.0157 (6) | 0.0163 (5) | 0.0190 (5) | −0.0004 (4) | 0.0029 (4) | 0.0001 (4) |
C1 | 0.0175 (8) | 0.0188 (8) | 0.0217 (8) | 0.0000 (7) | 0.0027 (7) | 0.0008 (7) |
C2 | 0.0394 (13) | 0.0782 (17) | 0.0312 (11) | −0.0185 (12) | 0.0099 (10) | −0.0194 (11) |
C3 | 0.0229 (10) | 0.0477 (12) | 0.0440 (12) | −0.0044 (9) | 0.0043 (9) | −0.0120 (10) |
C4 | 0.0436 (13) | 0.0230 (10) | 0.0670 (15) | −0.0028 (9) | 0.0042 (12) | −0.0077 (9) |
C5 | 0.0253 (10) | 0.0158 (8) | 0.0236 (8) | −0.0005 (7) | 0.0032 (7) | 0.0020 (7) |
C6 | 0.0338 (11) | 0.0287 (10) | 0.0317 (10) | −0.0007 (8) | 0.0079 (8) | 0.0097 (8) |
C7 | 0.0359 (13) | 0.0507 (13) | 0.0620 (15) | 0.0190 (10) | 0.0188 (11) | 0.0279 (11) |
C8 | 0.0449 (14) | 0.0482 (12) | 0.0349 (11) | −0.0146 (11) | −0.0062 (10) | 0.0091 (9) |
C9 | 0.0248 (10) | 0.0268 (9) | 0.0194 (8) | −0.0033 (8) | 0.0044 (7) | −0.0006 (7) |
C10 | 0.0529 (16) | 0.0884 (18) | 0.0410 (12) | 0.0210 (14) | 0.0291 (12) | 0.0210 (13) |
C11 | 0.0580 (16) | 0.0684 (16) | 0.0438 (13) | −0.0359 (13) | −0.0104 (12) | 0.0235 (12) |
C12 | 0.0417 (13) | 0.0393 (11) | 0.0280 (10) | −0.0021 (9) | 0.0059 (9) | 0.0048 (8) |
Mg1—O1 | 2.0274 (12) | C2—H2A | 0.9800 |
Mg1—O1i | 2.0347 (11) | C2—H2B | 0.9800 |
Mg1—C5 | 2.1915 (17) | C2—H2C | 0.9800 |
Mg1—C9i | 2.1890 (17) | C3—H3A | 0.9800 |
Mg1—Mg1i | 3.0004 (10) | C3—H3B | 0.9800 |
Mg1—Na1i | 3.1096 (8) | C3—H3C | 0.9800 |
Mg1—Na1 | 3.1332 (8) | C4—H4A | 0.9800 |
Na1—O1 | 2.2716 (12) | C4—H4B | 0.9800 |
Na1—C5 | 2.6850 (18) | C4—H4C | 0.9800 |
Na1—C9 | 2.6706 (18) | C5—H5A | 0.98 (2) |
Na1—C6ii | 2.7448 (18) | C5—H5B | 0.89 (2) |
Na1—Mg1i | 3.1096 (8) | C6—H6A | 0.9800 |
Na1—Si1 | 3.4416 (9) | C6—H6B | 0.9800 |
Na1—H5A | 2.45 (2) | C6—H6C | 0.9800 |
Na1—H5B | 2.44 (2) | C7—H7A | 0.9800 |
Na1—H9A | 2.466 (17) | C7—H7B | 0.9800 |
Na1—H9B | 2.385 (18) | C7—H7C | 0.9800 |
Si1—C3 | 1.862 (2) | C8—H8A | 0.9800 |
Si1—C4 | 1.864 (2) | C8—H8B | 0.9800 |
Si1—C2 | 1.870 (2) | C8—H8C | 0.9800 |
Si1—C1 | 1.8725 (17) | C9—Mg1i | 2.1890 (17) |
Si2—C5 | 1.8257 (18) | C9—H9A | 0.979 (19) |
Si2—C7 | 1.871 (2) | C9—H9B | 0.991 (19) |
Si2—C8 | 1.871 (2) | C10—H10A | 0.9800 |
Si2—C6 | 1.8868 (17) | C10—H10B | 0.9800 |
Si3—C9 | 1.8401 (17) | C10—H10C | 0.9800 |
Si3—C11 | 1.868 (2) | C11—H11A | 0.9800 |
Si3—C12 | 1.873 (2) | C11—H11B | 0.9800 |
Si3—C10 | 1.879 (2) | C11—H11C | 0.9800 |
O1—C1 | 1.4342 (19) | C12—H12A | 0.9800 |
O1—Mg1i | 2.0347 (11) | C12—H12B | 0.9800 |
C1—H1A | 0.966 (17) | C12—H12C | 0.9800 |
C1—H1B | 1.041 (17) | ||
O1—Mg1—O1i | 84.77 (5) | C9—Si3—C11 | 110.08 (9) |
O1—Mg1—C9i | 110.06 (6) | C9—Si3—C12 | 111.27 (9) |
O1i—Mg1—C9i | 102.46 (6) | C11—Si3—C12 | 108.79 (10) |
O1—Mg1—C5 | 102.52 (6) | C9—Si3—C10 | 113.32 (10) |
O1i—Mg1—C5 | 106.08 (6) | C11—Si3—C10 | 106.58 (13) |
C9i—Mg1—C5 | 138.14 (7) | C12—Si3—C10 | 106.58 (10) |
O1—Mg1—Mg1i | 42.48 (3) | C1—O1—Mg1 | 122.69 (9) |
O1i—Mg1—Mg1i | 42.29 (3) | C1—O1—Mg1i | 122.22 (9) |
C9i—Mg1—Mg1i | 112.22 (5) | Mg1—O1—Mg1i | 95.23 (5) |
C5—Mg1—Mg1i | 109.53 (5) | C1—O1—Na1 | 123.01 (9) |
O1—Mg1—Na1i | 89.07 (3) | Mg1—O1—Na1 | 93.40 (5) |
O1i—Mg1—Na1i | 46.88 (3) | Mg1i—O1—Na1 | 92.29 (5) |
C9i—Mg1—Na1i | 57.43 (5) | O1—C1—Si1 | 113.78 (11) |
C5—Mg1—Na1i | 150.02 (6) | O1—C1—H1A | 109.9 (10) |
Mg1i—Mg1—Na1i | 61.67 (2) | Si1—C1—H1A | 107.3 (10) |
O1—Mg1—Na1 | 46.36 (3) | O1—C1—H1B | 110.7 (10) |
O1i—Mg1—Na1 | 88.28 (3) | Si1—C1—H1B | 108.4 (9) |
C9i—Mg1—Na1 | 153.69 (6) | H1A—C1—H1B | 106.4 (13) |
C5—Mg1—Na1 | 57.34 (5) | Si1—C2—H2A | 109.5 |
Mg1i—Mg1—Na1 | 60.88 (2) | Si1—C2—H2B | 109.5 |
Na1i—Mg1—Na1 | 122.550 (19) | H2A—C2—H2B | 109.5 |
O1—Na1—C9 | 83.19 (5) | Si1—C2—H2C | 109.5 |
O1—Na1—C5 | 82.79 (5) | H2A—C2—H2C | 109.5 |
C9—Na1—C5 | 116.83 (6) | H2B—C2—H2C | 109.5 |
O1—Na1—C6ii | 171.69 (6) | Si1—C3—H3A | 109.5 |
C9—Na1—C6ii | 104.77 (6) | Si1—C3—H3B | 109.5 |
C5—Na1—C6ii | 95.46 (6) | H3A—C3—H3B | 109.5 |
O1—Na1—Mg1i | 40.83 (3) | Si1—C3—H3C | 109.5 |
C9—Na1—Mg1i | 43.69 (4) | H3A—C3—H3C | 109.5 |
C5—Na1—Mg1i | 94.54 (4) | H3B—C3—H3C | 109.5 |
C6ii—Na1—Mg1i | 147.46 (5) | Si1—C4—H4A | 109.5 |
O1—Na1—Mg1 | 40.24 (3) | Si1—C4—H4B | 109.5 |
C9—Na1—Mg1 | 96.21 (4) | H4A—C4—H4B | 109.5 |
C5—Na1—Mg1 | 43.41 (4) | Si1—C4—H4C | 109.5 |
C6ii—Na1—Mg1 | 138.84 (5) | H4A—C4—H4C | 109.5 |
Mg1i—Na1—Mg1 | 57.450 (19) | H4B—C4—H4C | 109.5 |
O1—Na1—Si1 | 53.61 (3) | Si2—C5—Mg1 | 119.04 (9) |
C9—Na1—Si1 | 112.03 (5) | Si2—C5—Na1 | 161.64 (9) |
C5—Na1—Si1 | 107.41 (4) | Mg1—C5—Na1 | 79.25 (5) |
C6ii—Na1—Si1 | 119.83 (5) | Si2—C5—H5A | 105.5 (12) |
Mg1i—Na1—Si1 | 86.17 (2) | Mg1—C5—H5A | 103.8 (11) |
Mg1—Na1—Si1 | 82.41 (2) | Na1—C5—H5A | 65.7 (12) |
O1—Na1—H5A | 93.8 (5) | Si2—C5—H5B | 105.4 (13) |
C9—Na1—H5A | 100.1 (5) | Mg1—C5—H5B | 115.0 (13) |
C5—Na1—H5A | 21.5 (5) | Na1—C5—H5B | 64.7 (13) |
C6ii—Na1—H5A | 87.2 (5) | H5A—C5—H5B | 107.3 (17) |
Mg1i—Na1—H5A | 91.0 (4) | Si2—C6—H6A | 109.5 |
Mg1—Na1—H5A | 54.0 (5) | Si2—C6—H6B | 109.5 |
Si1—Na1—H5A | 128.4 (5) | H6A—C6—H6B | 109.5 |
O1—Na1—H5B | 91.1 (5) | Si2—C6—H6C | 109.5 |
C9—Na1—H5B | 135.4 (5) | H6A—C6—H6C | 109.5 |
C5—Na1—H5B | 19.2 (5) | H6B—C6—H6C | 109.5 |
C6ii—Na1—H5B | 84.9 (5) | Si2—C7—H7A | 109.5 |
Mg1i—Na1—H5B | 111.7 (5) | Si2—C7—H7B | 109.5 |
Mg1—Na1—H5B | 56.0 (5) | H7A—C7—H7B | 109.5 |
Si1—Na1—H5B | 99.1 (5) | Si2—C7—H7C | 109.5 |
H5A—Na1—H5B | 35.9 (6) | H7A—C7—H7C | 109.5 |
O1—Na1—H9A | 89.2 (4) | H7B—C7—H7C | 109.5 |
C9—Na1—H9A | 21.5 (5) | Si2—C8—H8A | 109.5 |
C5—Na1—H9A | 138.3 (5) | Si2—C8—H8B | 109.5 |
C6ii—Na1—H9A | 97.4 (4) | H8A—C8—H8B | 109.5 |
Mg1i—Na1—H9A | 56.2 (4) | Si2—C8—H8C | 109.5 |
Mg1—Na1—H9A | 113.2 (4) | H8A—C8—H8C | 109.5 |
Si1—Na1—H9A | 100.1 (4) | H8B—C8—H8C | 109.5 |
H5A—Na1—H9A | 120.4 (7) | Si3—C9—Mg1i | 122.00 (9) |
H5B—Na1—H9A | 156.3 (7) | Si3—C9—Na1 | 158.38 (9) |
O1—Na1—H9B | 95.4 (4) | Mg1i—C9—Na1 | 78.88 (5) |
C9—Na1—H9B | 21.7 (5) | Si3—C9—H9A | 106.2 (10) |
C5—Na1—H9B | 100.8 (5) | Mg1i—C9—H9A | 110.1 (10) |
C6ii—Na1—H9B | 92.9 (4) | Na1—C9—H9A | 67.4 (10) |
Mg1i—Na1—H9B | 54.7 (4) | Si3—C9—H9B | 103.6 (11) |
Mg1—Na1—H9B | 94.2 (4) | Mg1i—C9—H9B | 103.6 (11) |
Si1—Na1—H9B | 133.3 (5) | Na1—C9—H9B | 62.7 (11) |
H5A—Na1—H9B | 81.5 (7) | H9A—C9—H9B | 111.1 (15) |
H5B—Na1—H9B | 117.4 (7) | Si3—C10—H10A | 109.5 |
H9A—Na1—H9B | 39.1 (6) | Si3—C10—H10B | 109.5 |
C3—Si1—C4 | 109.76 (10) | H10A—C10—H10B | 109.5 |
C3—Si1—C2 | 110.13 (10) | Si3—C10—H10C | 109.5 |
C4—Si1—C2 | 109.72 (11) | H10A—C10—H10C | 109.5 |
C3—Si1—C1 | 108.12 (8) | H10B—C10—H10C | 109.5 |
C4—Si1—C1 | 109.58 (9) | Si3—C11—H11A | 109.5 |
C2—Si1—C1 | 109.51 (9) | Si3—C11—H11B | 109.5 |
C3—Si1—Na1 | 176.36 (7) | H11A—C11—H11B | 109.5 |
C4—Si1—Na1 | 73.68 (7) | Si3—C11—H11C | 109.5 |
C2—Si1—Na1 | 69.18 (7) | H11A—C11—H11C | 109.5 |
C1—Si1—Na1 | 69.16 (5) | H11B—C11—H11C | 109.5 |
C5—Si2—C7 | 114.08 (9) | Si3—C12—H12A | 109.5 |
C5—Si2—C8 | 112.33 (9) | Si3—C12—H12B | 109.5 |
C7—Si2—C8 | 106.86 (11) | H12A—C12—H12B | 109.5 |
C5—Si2—C6 | 109.16 (9) | Si3—C12—H12C | 109.5 |
C7—Si2—C6 | 106.38 (9) | H12A—C12—H12C | 109.5 |
C8—Si2—C6 | 107.69 (9) | H12B—C12—H12C | 109.5 |
O1i—Mg1—Na1—O1 | 84.41 (6) | Si1—Na1—O1—Mg1 | −128.08 (5) |
C9i—Mg1—Na1—O1 | −30.82 (12) | C9—Na1—O1—Mg1i | 12.68 (5) |
C5—Mg1—Na1—O1 | −165.20 (8) | C5—Na1—O1—Mg1i | −105.57 (5) |
Mg1i—Mg1—Na1—O1 | 50.55 (4) | Mg1—Na1—O1—Mg1i | −95.38 (5) |
Na1i—Mg1—Na1—O1 | 50.55 (4) | Si1—Na1—O1—Mg1i | 136.54 (5) |
O1—Mg1—Na1—C9 | −71.74 (6) | Mg1—O1—C1—Si1 | 111.87 (10) |
O1i—Mg1—Na1—C9 | 12.68 (6) | Mg1i—O1—C1—Si1 | −125.95 (9) |
C9i—Mg1—Na1—C9 | −102.56 (11) | Na1—O1—C1—Si1 | −8.20 (15) |
C5—Mg1—Na1—C9 | 123.06 (8) | C3—Si1—C1—O1 | −177.72 (12) |
Mg1i—Mg1—Na1—C9 | −21.18 (5) | C4—Si1—C1—O1 | −58.12 (14) |
Na1i—Mg1—Na1—C9 | −21.18 (5) | C2—Si1—C1—O1 | 62.27 (14) |
O1—Mg1—Na1—C5 | 165.20 (8) | Na1—Si1—C1—O1 | 4.84 (9) |
O1i—Mg1—Na1—C5 | −110.38 (7) | C7—Si2—C5—Mg1 | 151.08 (11) |
C9i—Mg1—Na1—C5 | 134.39 (13) | C8—Si2—C5—Mg1 | 29.28 (14) |
Mg1i—Mg1—Na1—C5 | −144.24 (7) | C6—Si2—C5—Mg1 | −90.09 (11) |
Na1i—Mg1—Na1—C5 | −144.24 (7) | C7—Si2—C5—Na1 | −23.7 (3) |
O1—Mg1—Na1—C6ii | 167.32 (9) | C8—Si2—C5—Na1 | −145.5 (3) |
O1i—Mg1—Na1—C6ii | −108.27 (8) | C6—Si2—C5—Na1 | 95.1 (3) |
C9i—Mg1—Na1—C6ii | 136.50 (13) | O1—Mg1—C5—Si2 | 170.76 (9) |
C5—Mg1—Na1—C6ii | 2.11 (9) | O1i—Mg1—C5—Si2 | −101.14 (10) |
Mg1i—Mg1—Na1—C6ii | −142.13 (8) | C9i—Mg1—C5—Si2 | 30.01 (17) |
Na1i—Mg1—Na1—C6ii | −142.13 (8) | Mg1i—Mg1—C5—Si2 | −145.53 (8) |
O1—Mg1—Na1—Mg1i | −50.55 (4) | Na1i—Mg1—C5—Si2 | −78.66 (14) |
O1i—Mg1—Na1—Mg1i | 33.86 (3) | Na1—Mg1—C5—Si2 | −178.33 (13) |
C9i—Mg1—Na1—Mg1i | −81.37 (12) | O1—Mg1—C5—Na1 | −10.91 (6) |
C5—Mg1—Na1—Mg1i | 144.24 (7) | O1i—Mg1—C5—Na1 | 77.19 (5) |
Na1i—Mg1—Na1—Mg1i | 0.0 | C9i—Mg1—C5—Na1 | −151.66 (9) |
O1—Mg1—Na1—Si1 | 39.73 (4) | Mg1i—Mg1—C5—Na1 | 32.80 (6) |
O1i—Mg1—Na1—Si1 | 124.15 (4) | Na1i—Mg1—C5—Na1 | 99.66 (9) |
C9i—Mg1—Na1—Si1 | 8.92 (12) | O1—Na1—C5—Si2 | −175.1 (3) |
C5—Mg1—Na1—Si1 | −125.47 (6) | C9—Na1—C5—Si2 | 106.3 (3) |
Mg1i—Mg1—Na1—Si1 | 90.29 (2) | C6ii—Na1—C5—Si2 | −3.3 (3) |
Na1i—Mg1—Na1—Si1 | 90.29 (2) | Mg1i—Na1—C5—Si2 | 145.7 (3) |
O1i—Mg1—O1—C1 | 134.03 (12) | Mg1—Na1—C5—Si2 | 175.3 (4) |
C9i—Mg1—O1—C1 | 32.65 (12) | Si1—Na1—C5—Si2 | −126.9 (3) |
C5—Mg1—O1—C1 | −120.63 (11) | O1—Na1—C5—Mg1 | 9.57 (5) |
Mg1i—Mg1—O1—C1 | 134.03 (12) | C9—Na1—C5—Mg1 | −69.01 (7) |
Na1i—Mg1—O1—C1 | 87.26 (10) | C6ii—Na1—C5—Mg1 | −178.60 (6) |
Na1—Mg1—O1—C1 | −133.36 (12) | Mg1i—Na1—C5—Mg1 | −29.61 (5) |
O1i—Mg1—O1—Mg1i | 0.0 | Si1—Na1—C5—Mg1 | 57.79 (5) |
C9i—Mg1—O1—Mg1i | −101.38 (6) | C11—Si3—C9—Mg1i | −42.80 (15) |
C5—Mg1—O1—Mg1i | 105.34 (6) | C12—Si3—C9—Mg1i | 77.89 (13) |
Na1i—Mg1—O1—Mg1i | −46.77 (3) | C10—Si3—C9—Mg1i | −162.03 (12) |
Na1—Mg1—O1—Mg1i | 92.61 (5) | C11—Si3—C9—Na1 | 120.8 (3) |
O1i—Mg1—O1—Na1 | −92.61 (5) | C12—Si3—C9—Na1 | −118.5 (3) |
C9i—Mg1—O1—Na1 | 166.01 (6) | C10—Si3—C9—Na1 | 1.6 (3) |
C5—Mg1—O1—Na1 | 12.72 (6) | O1—Na1—C9—Si3 | −177.9 (3) |
Mg1i—Mg1—O1—Na1 | −92.61 (5) | C5—Na1—C9—Si3 | −99.5 (3) |
Na1i—Mg1—O1—Na1 | −139.38 (3) | C6ii—Na1—C9—Si3 | 4.6 (3) |
C9—Na1—O1—C1 | −118.80 (11) | Mg1i—Na1—C9—Si3 | −165.9 (3) |
C5—Na1—O1—C1 | 122.95 (11) | Mg1—Na1—C9—Si3 | −139.7 (3) |
Mg1i—Na1—O1—C1 | −131.48 (12) | Si1—Na1—C9—Si3 | 136.0 (3) |
Mg1—Na1—O1—C1 | 133.14 (12) | O1—Na1—C9—Mg1i | −11.99 (5) |
Si1—Na1—O1—C1 | 5.06 (9) | C5—Na1—C9—Mg1i | 66.36 (7) |
C9—Na1—O1—Mg1 | 108.05 (6) | C6ii—Na1—C9—Mg1i | 170.45 (6) |
C5—Na1—O1—Mg1 | −10.19 (5) | Mg1—Na1—C9—Mg1i | 26.17 (6) |
Mg1i—Na1—O1—Mg1 | 95.38 (5) | Si1—Na1—C9—Mg1i | −58.13 (6) |
Symmetry codes: (i) −x, −y, −z; (ii) x, −y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Na2Mg2(C4H11OSi)2(C4H11Si)4] |
Mr | 649.91 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 123 |
a, b, c (Å) | 9.8057 (3), 18.1602 (5), 11.8234 (3) |
β (°) | 95.482 (3) |
V (Å3) | 2095.80 (10) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.27 |
Crystal size (mm) | 0.23 × 0.18 × 0.15 |
Data collection | |
Diffractometer | Oxford Gemini S diffractometer |
Absorption correction | Multi-scan (CrysAlis PRO; Oxford Diffraction, 2010) |
Tmin, Tmax | 0.804, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 17871, 5052, 3663 |
Rint | 0.046 |
(sin θ/λ)max (Å−1) | 0.660 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.100, 0.96 |
No. of reflections | 5052 |
No. of parameters | 196 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.46, −0.28 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2010), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001).
Mg1—O1 | 2.0274 (12) | Na1—O1 | 2.2716 (12) |
Mg1—O1i | 2.0347 (11) | Na1—C5 | 2.6850 (18) |
Mg1—C5 | 2.1915 (17) | Na1—C9 | 2.6706 (18) |
Mg1—C9i | 2.1890 (17) | Na1—C6ii | 2.7448 (18) |
O1—Mg1—O1i | 84.77 (5) | O1—Na1—C9 | 83.19 (5) |
O1—Mg1—C9i | 110.06 (6) | O1—Na1—C5 | 82.79 (5) |
O1i—Mg1—C9i | 102.46 (6) | C9—Na1—C5 | 116.83 (6) |
O1—Mg1—C5 | 102.52 (6) | O1—Na1—C6ii | 171.69 (6) |
O1i—Mg1—C5 | 106.08 (6) | C9—Na1—C6ii | 104.77 (6) |
C9i—Mg1—C5 | 138.14 (7) | C5—Na1—C6ii | 95.46 (6) |
Symmetry codes: (i) −x, −y, −z; (ii) x, −y+1/2, z+1/2. |
Alkali metal organometallic compounds can react violently with moisture and oxygen, hence the exclusion of air during the preparation and employment of these complexes is mandatory, with manipulations carried out under a dry inert atmosphere (Wardell, 1982, and references therein). Having stated that, regulated exposure of metal alkyls to dry oxygen can lead to an interesting array of structures, with oxygen inserting into the metal–carbon bond (Barron, 1993; Kennedy et al., 1999; Forbes et al., 2000; Mulvey, 2001; Bailey et al., 2003). Here, we report an example of controlled deliberate oxygen insertion into the homoleptic trisalkyl sodium magnesiate [{NaMgR3}]∞ (R = CH2SiMe3), a compound which itself has recently been structurally authenticated as a unique two-dimensional supramolecular network in the solid state (Baillie et al., 2011). A drying tube (containing CaCl2) was fitted to a Schlenk tube containing a solution of the starting magnesiate complex, to allow oxygen but to disallow moisture from entering the system. Slow cooling of the resulting colourless solution led to the deposition of colourless crystals of [{NaMgR2(OR)}]∞, (I), where the alkoxide ligand OR is formed as a result of oxygen insertion into the metal–carbon polar bond of an alkyl group.
Looking at its empirical formulation, (I) can be envisaged as the co-complexation product of the bis-alkyl Mg(CH2SiMe3)2 and the alkoxide NaOCH2SiMe3 and, as such, may be considered an alkaline earth metal relation of the Lochmann–Schlosser reagent, LiC-KOR, which pairs n-butyllithium with the heavier alkali metal potassium tert-butoxide (Lochmann, 2000). LiC-KOR can be described as a superbase, due to its dramatic enhancement in reactivity in deprotonation reactions compared with a mixture of an alkyllithium with lithium butoxide. Despite the wide applications of the superbase in synthesis, definitive structural information on the Lochmann–Schlosser reagent has not been forthcoming. However, elucidation of the structure of (I) may provide indirect insight into the structural make up of the alkali metal-rich superbase.
Compound (I) features a dimeric arrangement comprising two {NaMgR2(OR)} units, giving rise to a face-fused double heterocubane structure with two missing corners. The OR groups face-cap the `top' and `bottom' of the structure, acting as a bridge between two Mg atoms and an Na centre (Fig. 1). Alternatively, the compound can be described as an inverse crown complex consisting of a cationic eight-atom {NaCMgC}2 heterobimetallic ring hosting two alkoxide ligands at its core (Mulvey, 2001). This cationic ring adopts a pseudo-chair structure, with the Na atoms constituting the `head' and `footrest' of the chair (see the alternative view in Fig. 2).
The Mg atom resides in a four-coordinate environment, with widely varying bond angles [84.77 (5)–138.14 (7)°] and bonds to two alkyl groups and two alkoxide ligands; see Table 1 for more details and for a definition of the symmetry operators. Each Na atom bonds to two bridging alkyl groups within the dimeric unit and also to one alkoxide OCH2SiMe3 ligand. In addition, Na also forms a secondary intermolecular interaction with a neighbouring methyl group [Na1···C6ii = 2.7448 (18) Å]. Note that this interaction with a neutral methyl group is only about 0.06 Å longer than the interactions with the formally charged CH2R anions. The Na atom is thus tetracoordinate, with a wide range of angles observed from 82.79 (5) to 171.69 (6)°.
Unlike related inverse crown structures, where Lewis basic donors such as TMEDA (N,N,N',N'-tetramethylethylenediamine) coordinate to the alkali metal (Barnett et al., 2005) or alternatively where the alkali metal is coordinatively supported through metal–arene contacts from aromatic solvents (Gallagher et al., 2002; Andrikopoulos et al., 2003), no such stabilization is observed in (I). This lack of externally added solvating molecules around Na is compensated for by the additional secondary electrostatic interactions with the methyl groups of SiMe3 fragments from neighbouring molecules. Of the four alkyl groups present in the ring scaffold of (I), only two alkyl units, diagonally opposite each other and inversion related, interact with the neighbouring dimeric units. This leads to polymerization of the eight-membered rings and results in a two-dimensional coordination sheet propagating in the crystallographic bc plane (Fig. 3). Each plane has a core of polar elements surrounded by organic groups and thus a structure with alternating hydrophilic and hydrophobic layers results.
In the oxygen-free parent compound [{NaMgR3}]∞ (Baillie et al., 2011), a very different structure is observed, made up of 12-atom {(NaCMgC)3} fused rings. However, as in (I), each alkyl group acts as a bridge between an Na and an Mg centre, and similar distances are found in the Na—C bond lengths [2.6708 (19) Å]. In addition, the Mg—O distance in (I) is almost identical to those reported in the closely related inverse crown ether [{NaMg(Bu)2(OtBu).(TMEDA)}2] (Barnett et al., 2005) [compare Mg—O1 and Mg—O1i in Table 1 with Mg—O distances of 2.028 (4) and 2.033 (4) Å in the TMEDA-solvated structure]. To the best of our knowledge, this analogous structure is the only other inverse crown ether with the eight-membered scaffold constructed exclusively with metal–carbon bonds. In contrast with (I), [{NaMg(Bu)2(OtBu).(TMEDA)}2] was formed using a different synthetic approach by the co-complexation of the monometallic components NaOtBu and MgBu2 in the presence of TMEDA, which solvates the alkali metal and removes the opportunity for polymeric propagation.