metal-organic compounds
2,2′-Bis(4-methoxyphenyl)-2,2′-bis(trimethylsilanyloxy)-2,2′-(ferrocene-1,1′-diyl)diacetonitrile
aCollege of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China
*Correspondence e-mail: hxxwangxiaoli@163.com
In the title compound, [Fe(C17H20NO2Si)2], the Fe atom is situated on a crystallographic centre of inversion, leading to a perfectly of the Cp rings.
Related literature
For related literature, see: Evans & Truesdale (1973); Evans et al. (1974); Lidy & Sundermeyer (1973); Dunitz et al. (1956); Fischer & Hüning (1987); Fleming & Woolias (1979); Gassman & Talley (1978); Groutas & Felker (1980); Rasmussen & Heilmann (1978); Zhou (1989).
Experimental
Crystal data
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Data collection: SMART (Bruker, 2001); cell SMART; data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.
Supporting information
https://doi.org/10.1107/S1600536807064513/im2048sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807064513/im2048Isup2.hkl
Into a 100 ml 3-neck round-bottomed flask equipped with magnetic stirring bar, reflux condenser and CaCl2 drying tube was placed 1.1 mmol (297 mg) bisacetylferrocene in 15 ml dry CH2Cl2 and 1 mmol (319 mg) ZnI2. After stirring for 20 minutes, 4.4 mmol TMSCN (374 mg) were added and the was solution stirred for 10 h. During the reaction the progress of the reaction was monitored by TLC (benzene). After completion the solvent was evaporated under reduced pressure with the residue obtained being extracted with pentane. The solution was washed with saturated cold aqueous NaHSO3 and dried over Na2SO4. Filtration and removal of the solvent under reduced pressure yielded the crude product which was recrystallized from ether/light petroleum (b.p. 60–90°) to obtain single crystals the title compound.
All the H atoms were positioned geometrically and refined using a riding model with C—H distances of 0.93–0.97° and Uiso(H) = 1.2Ueq of the corresponding parent atom. The methyls at the terminal group have higher Ueq than silicon atom in the central tetrahedral.
Cyanohydrin trimethylsilyl α,β-unsaturated and β-aminoalcohols. The general method for the preparation of cyanohydrin trimethylsilyl is the addition of trimethylsilyl cyanide (TMSCN) to with the aid of a catalyst including Lewis acids, such as ZnI2 (Evans et al.,1974) and AlCl3 (Lidy et al., 1973), as well as solubilized anionic species, such as K+CN--18-Crown-6 and nBu4N+CN- (Evans et al.,1973).
are useful in organic synthesis as they serve not only for the protection of carbonyl groups (Rasmussen et al., 1978; Groutas et al., 1980; Fischer et al., 1987) but also as versatile intermediates (Gassman et al., 1978; Evans et al., 1974; Fleming et al., 1979) in the synthesis ofThe molecular structure of the title compound, (I), shows the Fe atom on a crystallographic center of inversion and two Cp ligands with a cyanohydrin ether substituents. Because of the inversion symmetry the Cp ligands show a ≡N, (CH3)3SiO and (CH3O)C6H4 groups in compound and is therefore a new stereogenic center which is formed during the reaction sequence. Due to the internal symmetry of the molecule Figure 1 shows the R,S diastereomer. There is no evidence for the formation of R,R- or S,S-diastereomers even from NMR spectra of the crude reaction product. The bond angle of C(6)–C(7)–N(1) is 178.9 (6)° showing sp for the C≡N carbon atom. The Si(1)—O(1)—C(6) bond angle measures to 131.6 (3)° which is significantly larger compared to that of a regular tetrahedron (109.5°). The influence of neighbouring Csp and Csp2 atoms shorten the C(6)–C(1), C(6)–C(7) and C(6)–C(8) bond distances (1.511 (6) Å, 1.483 (7) Å and 1.531 (6), respectively) compared to normal C—C bond distances (app. 1.54 Å). It shows there may be a super conjugate effect in the molecule of the title compound.
The central tetrahedral C(6) atom is bound to CFor related literature, see: Evans & Truesdale (1973); Evans et al. (1974); Lidy & Sundermeyer (1973); Dunitz et al. (1956); Fischer & Hüning (1987); Fleming & Woolias (1979); Gassman & Talley (1978); Groutas & Felker (1980); Rasmussen & Heilmann (1978); Zhou (1989).
Data collection: SMART (Bruker, 2001); cell
SMART (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).Fig. 1. The molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are represented by circles of arbitrary size. |
[Fe(C17H20NO2Si)2] | Z = 1 |
Mr = 652.71 | F(000) = 344 |
Triclinic, P1 | Dx = 1.295 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.129 (2) Å | Cell parameters from 749 reflections |
b = 10.500 (4) Å | θ = 2.5–25.4° |
c = 11.449 (4) Å | µ = 0.56 mm−1 |
α = 95.613 (5)° | T = 293 K |
β = 97.253 (6)° | Needle, yellow |
γ = 97.441 (6)° | 0.24 × 0.14 × 0.12 mm |
V = 837.3 (5) Å3 |
Bruker SMART CCD area-detector diffractometer | 3367 independent reflections |
Radiation source: fine-focus sealed tube | 2156 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
φ and ω scans | θmax = 26.4°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −7→8 |
Tmin = 0.822, Tmax = 1.000 | k = −10→13 |
4803 measured reflections | l = −14→14 |
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)] = 0.063 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.204 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.111P)2 + 0.2987P] where P = (Fo2 + 2Fc2)/3 |
3367 reflections | (Δ/σ)max < 0.001 |
196 parameters | Δρmax = 0.98 e Å−3 |
21 restraints | Δρmin = −0.43 e Å−3 |
[Fe(C17H20NO2Si)2] | γ = 97.441 (6)° |
Mr = 652.71 | V = 837.3 (5) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.129 (2) Å | Mo Kα radiation |
b = 10.500 (4) Å | µ = 0.56 mm−1 |
c = 11.449 (4) Å | T = 293 K |
α = 95.613 (5)° | 0.24 × 0.14 × 0.12 mm |
β = 97.253 (6)° |
Bruker SMART CCD area-detector diffractometer | 3367 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 2156 reflections with I > 2σ(I) |
Tmin = 0.822, Tmax = 1.000 | Rint = 0.030 |
4803 measured reflections |
R[F2 > 2σ(F2)] = 0.063 | 21 restraints |
wR(F2) = 0.204 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.98 e Å−3 |
3367 reflections | Δρmin = −0.43 e Å−3 |
196 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 | ||
Fe2 | 1.0000 | 0.0000 | 0.0000 | 0.0414 (3) | |
Si1 | 1.0979 (2) | 0.43619 (14) | 0.25558 (15) | 0.0644 (5) | |
N1 | 0.6209 (8) | 0.2641 (6) | 0.0446 (5) | 0.0789 (15) | |
O1 | 1.0478 (5) | 0.2772 (3) | 0.2175 (3) | 0.0539 (9) | |
O2 | 0.6132 (6) | 0.1608 (4) | 0.6498 (3) | 0.0687 (11) | |
C1 | 0.9125 (6) | 0.0596 (4) | 0.1571 (4) | 0.0410 (10) | |
C2 | 1.0873 (7) | 0.0084 (5) | 0.1784 (4) | 0.0480 (11) | |
H2 | 1.2020 | 0.0520 | 0.2196 | 0.058* | |
C3 | 1.0536 (9) | −0.1225 (5) | 0.1245 (4) | 0.0597 (14) | |
H3 | 1.1433 | −0.1794 | 0.1250 | 0.072* | |
C4 | 0.8633 (10) | −0.1509 (5) | 0.0708 (4) | 0.0635 (16) | |
H4 | 0.8054 | −0.2297 | 0.0294 | 0.076* | |
C5 | 0.7750 (8) | −0.0411 (5) | 0.0897 (4) | 0.0532 (13) | |
H5 | 0.6483 | −0.0343 | 0.0630 | 0.064* | |
C6 | 0.8760 (6) | 0.1923 (4) | 0.2043 (4) | 0.0423 (10) | |
C7 | 0.7336 (8) | 0.2337 (5) | 0.1153 (4) | 0.0544 (13) | |
C8 | 0.7960 (6) | 0.1835 (4) | 0.3217 (4) | 0.0416 (10) | |
C9 | 0.9140 (7) | 0.1609 (5) | 0.4202 (4) | 0.0521 (12) | |
H9 | 1.0403 | 0.1511 | 0.4138 | 0.063* | |
C10 | 0.8494 (7) | 0.1524 (5) | 0.5273 (4) | 0.0538 (12) | |
H10 | 0.9319 | 0.1371 | 0.5924 | 0.065* | |
C11 | 0.6624 (7) | 0.1664 (5) | 0.5393 (4) | 0.0492 (12) | |
C12 | 0.5414 (7) | 0.1855 (5) | 0.4407 (4) | 0.0543 (12) | |
H12 | 0.4139 | 0.1919 | 0.4462 | 0.065* | |
C13 | 0.6097 (7) | 0.1950 (5) | 0.3340 (4) | 0.0503 (12) | |
H13 | 0.5272 | 0.2096 | 0.2686 | 0.060* | |
C14 | 0.4225 (9) | 0.1780 (7) | 0.6651 (5) | 0.0824 (19) | |
H14A | 0.4054 | 0.1719 | 0.7463 | 0.124* | |
H14B | 0.3345 | 0.1121 | 0.6148 | 0.124* | |
H14C | 0.3989 | 0.2615 | 0.6446 | 0.124* | |
C15 | 1.2315 (13) | 0.4614 (8) | 0.4056 (7) | 0.122 (3) | |
H15A | 1.3430 | 0.4189 | 0.4066 | 0.183* | |
H15B | 1.1520 | 0.4262 | 0.4598 | 0.183* | |
H15C | 1.2695 | 0.5523 | 0.4291 | 0.183* | |
C16 | 0.8845 (10) | 0.5181 (7) | 0.2564 (7) | 0.098 (2) | |
H16A | 0.8091 | 0.4851 | 0.3136 | 0.146* | |
H16B | 0.8101 | 0.5025 | 0.1792 | 0.146* | |
H16C | 0.9232 | 0.6094 | 0.2770 | 0.146* | |
C17 | 1.2491 (13) | 0.4952 (9) | 0.1477 (8) | 0.133 (3) | |
H17A | 1.3593 | 0.4512 | 0.1500 | 0.200* | |
H17B | 1.2894 | 0.5865 | 0.1671 | 0.200* | |
H17C | 1.1776 | 0.4788 | 0.0695 | 0.200* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Fe2 | 0.0614 (7) | 0.0322 (5) | 0.0294 (5) | −0.0005 (4) | 0.0117 (4) | 0.0011 (3) |
Si1 | 0.0751 (11) | 0.0402 (8) | 0.0728 (10) | −0.0016 (7) | 0.0095 (8) | −0.0043 (7) |
N1 | 0.084 (4) | 0.087 (4) | 0.070 (3) | 0.018 (3) | 0.012 (3) | 0.025 (3) |
O1 | 0.055 (2) | 0.0387 (17) | 0.066 (2) | −0.0051 (14) | 0.0222 (16) | −0.0050 (15) |
O2 | 0.083 (3) | 0.082 (3) | 0.050 (2) | 0.017 (2) | 0.0323 (19) | 0.0128 (19) |
C1 | 0.049 (3) | 0.040 (2) | 0.034 (2) | 0.0011 (19) | 0.0119 (19) | 0.0049 (18) |
C2 | 0.066 (3) | 0.049 (3) | 0.030 (2) | 0.012 (2) | 0.007 (2) | 0.0025 (19) |
C3 | 0.099 (5) | 0.047 (3) | 0.042 (3) | 0.025 (3) | 0.025 (3) | 0.011 (2) |
C4 | 0.113 (5) | 0.034 (3) | 0.042 (3) | −0.008 (3) | 0.026 (3) | 0.003 (2) |
C5 | 0.061 (3) | 0.050 (3) | 0.042 (2) | −0.016 (2) | 0.012 (2) | 0.003 (2) |
C6 | 0.046 (3) | 0.039 (2) | 0.040 (2) | −0.0013 (19) | 0.014 (2) | −0.0024 (18) |
C7 | 0.069 (3) | 0.054 (3) | 0.048 (3) | 0.017 (3) | 0.023 (3) | 0.017 (2) |
C8 | 0.048 (3) | 0.038 (2) | 0.038 (2) | 0.0016 (19) | 0.009 (2) | −0.0005 (18) |
C9 | 0.045 (3) | 0.060 (3) | 0.054 (3) | 0.012 (2) | 0.015 (2) | 0.002 (2) |
C10 | 0.060 (3) | 0.061 (3) | 0.042 (3) | 0.013 (2) | 0.009 (2) | 0.004 (2) |
C11 | 0.062 (3) | 0.044 (3) | 0.043 (2) | 0.003 (2) | 0.023 (2) | 0.000 (2) |
C12 | 0.047 (3) | 0.063 (3) | 0.057 (3) | 0.013 (2) | 0.019 (2) | 0.007 (2) |
C13 | 0.042 (3) | 0.062 (3) | 0.047 (3) | 0.008 (2) | 0.008 (2) | 0.007 (2) |
C14 | 0.092 (5) | 0.092 (5) | 0.076 (4) | 0.016 (4) | 0.053 (4) | 0.018 (3) |
C15 | 0.136 (5) | 0.096 (4) | 0.122 (5) | 0.017 (4) | −0.015 (4) | −0.007 (4) |
C16 | 0.101 (4) | 0.079 (4) | 0.112 (4) | 0.022 (3) | 0.012 (3) | −0.001 (3) |
C17 | 0.141 (5) | 0.118 (5) | 0.143 (5) | −0.004 (4) | 0.045 (4) | 0.023 (4) |
Fe2—C5 | 2.034 (5) | C4—H4 | 0.9300 |
Fe2—C5i | 2.034 (5) | C5—H5 | 0.9300 |
Fe2—C4 | 2.042 (5) | C6—C7 | 1.483 (7) |
Fe2—C4i | 2.042 (5) | C6—C8 | 1.531 (6) |
Fe2—C1 | 2.044 (4) | C8—C13 | 1.373 (6) |
Fe2—C1i | 2.044 (4) | C8—C9 | 1.379 (6) |
Fe2—C3 | 2.045 (5) | C9—C10 | 1.370 (6) |
Fe2—C3i | 2.045 (5) | C9—H9 | 0.9300 |
Fe2—C2 | 2.048 (4) | C10—C11 | 1.382 (7) |
Fe2—C2i | 2.048 (4) | C10—H10 | 0.9300 |
Si1—O1 | 1.663 (3) | C11—C12 | 1.378 (7) |
Si1—C15 | 1.833 (7) | C12—C13 | 1.378 (6) |
Si1—C17 | 1.841 (8) | C12—H12 | 0.9300 |
Si1—C16 | 1.842 (7) | C13—H13 | 0.9300 |
N1—C7 | 1.164 (7) | C14—H14A | 0.9600 |
O1—C6 | 1.401 (5) | C14—H14B | 0.9600 |
O2—C11 | 1.360 (5) | C14—H14C | 0.9600 |
O2—C14 | 1.425 (7) | C15—H15A | 0.9600 |
C1—C2 | 1.422 (7) | C15—H15B | 0.9600 |
C1—C5 | 1.433 (6) | C15—H15C | 0.9600 |
C1—C6 | 1.511 (6) | C16—H16A | 0.9600 |
C2—C3 | 1.428 (7) | C16—H16B | 0.9600 |
C2—H2 | 0.9300 | C16—H16C | 0.9600 |
C3—C4 | 1.399 (8) | C17—H17A | 0.9600 |
C3—H3 | 0.9300 | C17—H17B | 0.9600 |
C4—C5 | 1.395 (8) | C17—H17C | 0.9600 |
C5—Fe2—C5i | 180.0 (3) | C4—C3—Fe2 | 69.9 (3) |
C5—Fe2—C4 | 40.0 (2) | C2—C3—Fe2 | 69.7 (3) |
C5i—Fe2—C4 | 140.0 (2) | C4—C3—H3 | 125.7 |
C5—Fe2—C4i | 140.0 (2) | C2—C3—H3 | 125.7 |
C5i—Fe2—C4i | 40.0 (2) | Fe2—C3—H3 | 126.3 |
C4—Fe2—C4i | 180.0 (3) | C5—C4—C3 | 108.5 (4) |
C5—Fe2—C1 | 41.15 (17) | C5—C4—Fe2 | 69.7 (3) |
C5i—Fe2—C1 | 138.85 (17) | C3—C4—Fe2 | 70.1 (3) |
C4—Fe2—C1 | 68.36 (18) | C5—C4—H4 | 125.8 |
C4i—Fe2—C1 | 111.64 (18) | C3—C4—H4 | 125.8 |
C5—Fe2—C1i | 138.85 (17) | Fe2—C4—H4 | 126.0 |
C5i—Fe2—C1i | 41.15 (17) | C4—C5—C1 | 108.5 (5) |
C4—Fe2—C1i | 111.64 (18) | C4—C5—Fe2 | 70.3 (3) |
C4i—Fe2—C1i | 68.36 (18) | C1—C5—Fe2 | 69.8 (2) |
C1—Fe2—C1i | 180.00 (11) | C4—C5—H5 | 125.8 |
C5—Fe2—C3 | 67.6 (2) | C1—C5—H5 | 125.8 |
C5i—Fe2—C3 | 112.4 (2) | Fe2—C5—H5 | 125.7 |
C4—Fe2—C3 | 40.0 (2) | O1—C6—C7 | 109.7 (4) |
C4i—Fe2—C3 | 140.0 (2) | O1—C6—C1 | 108.4 (4) |
C1—Fe2—C3 | 68.23 (19) | C7—C6—C1 | 107.3 (4) |
C1i—Fe2—C3 | 111.77 (19) | O1—C6—C8 | 112.2 (3) |
C5—Fe2—C3i | 112.4 (2) | C7—C6—C8 | 110.0 (4) |
C5i—Fe2—C3i | 67.6 (2) | C1—C6—C8 | 108.9 (4) |
C4—Fe2—C3i | 140.0 (2) | N1—C7—C6 | 178.9 (6) |
C4i—Fe2—C3i | 40.0 (2) | C13—C8—C9 | 117.6 (4) |
C1—Fe2—C3i | 111.77 (19) | C13—C8—C6 | 123.2 (4) |
C1i—Fe2—C3i | 68.23 (19) | C9—C8—C6 | 119.2 (4) |
C3—Fe2—C3i | 180.0 (4) | C10—C9—C8 | 121.5 (4) |
C5—Fe2—C2 | 68.5 (2) | C10—C9—H9 | 119.3 |
C5i—Fe2—C2 | 111.5 (2) | C8—C9—H9 | 119.3 |
C4—Fe2—C2 | 68.3 (2) | C9—C10—C11 | 120.5 (5) |
C4i—Fe2—C2 | 111.7 (2) | C9—C10—H10 | 119.8 |
C1—Fe2—C2 | 40.67 (18) | C11—C10—H10 | 119.8 |
C1i—Fe2—C2 | 139.33 (18) | O2—C11—C12 | 125.1 (5) |
C3—Fe2—C2 | 40.83 (19) | O2—C11—C10 | 116.2 (5) |
C3i—Fe2—C2 | 139.17 (19) | C12—C11—C10 | 118.7 (4) |
C5—Fe2—C2i | 111.5 (2) | C13—C12—C11 | 120.0 (4) |
C5i—Fe2—C2i | 68.5 (2) | C13—C12—H12 | 120.0 |
C4—Fe2—C2i | 111.7 (2) | C11—C12—H12 | 120.0 |
C4i—Fe2—C2i | 68.3 (2) | C8—C13—C12 | 121.8 (5) |
C1—Fe2—C2i | 139.33 (18) | C8—C13—H13 | 119.1 |
C1i—Fe2—C2i | 40.67 (18) | C12—C13—H13 | 119.1 |
C3—Fe2—C2i | 139.17 (19) | O2—C14—H14A | 109.5 |
C3i—Fe2—C2i | 40.83 (19) | O2—C14—H14B | 109.5 |
C2—Fe2—C2i | 180.00 (7) | H14A—C14—H14B | 109.5 |
O1—Si1—C15 | 107.0 (3) | O2—C14—H14C | 109.5 |
O1—Si1—C17 | 105.0 (3) | H14A—C14—H14C | 109.5 |
C15—Si1—C17 | 110.9 (4) | H14B—C14—H14C | 109.5 |
O1—Si1—C16 | 113.7 (3) | Si1—C15—H15A | 109.5 |
C15—Si1—C16 | 108.6 (4) | Si1—C15—H15B | 109.5 |
C17—Si1—C16 | 111.7 (4) | H15A—C15—H15B | 109.5 |
C6—O1—Si1 | 131.6 (3) | Si1—C15—H15C | 109.5 |
C11—O2—C14 | 117.4 (4) | H15A—C15—H15C | 109.5 |
C2—C1—C5 | 107.2 (4) | H15B—C15—H15C | 109.5 |
C2—C1—C6 | 126.1 (4) | Si1—C16—H16A | 109.5 |
C5—C1—C6 | 126.6 (4) | Si1—C16—H16B | 109.5 |
C2—C1—Fe2 | 69.8 (2) | H16A—C16—H16B | 109.5 |
C5—C1—Fe2 | 69.0 (2) | Si1—C16—H16C | 109.5 |
C6—C1—Fe2 | 129.5 (3) | H16A—C16—H16C | 109.5 |
C1—C2—C3 | 107.2 (4) | H16B—C16—H16C | 109.5 |
C1—C2—Fe2 | 69.5 (2) | Si1—C17—H17A | 109.5 |
C3—C2—Fe2 | 69.5 (3) | Si1—C17—H17B | 109.5 |
C1—C2—H2 | 126.4 | H17A—C17—H17B | 109.5 |
C3—C2—H2 | 126.4 | Si1—C17—H17C | 109.5 |
Fe2—C2—H2 | 126.2 | H17A—C17—H17C | 109.5 |
C4—C3—C2 | 108.6 (5) | H17B—C17—H17C | 109.5 |
C15—Si1—O1—C6 | 108.2 (5) | C4i—Fe2—C4—C5 | 17 (100) |
C17—Si1—O1—C6 | −134.0 (5) | C1—Fe2—C4—C5 | 38.1 (3) |
C16—Si1—O1—C6 | −11.6 (5) | C1i—Fe2—C4—C5 | −141.9 (3) |
C5—Fe2—C1—C2 | 118.6 (4) | C3—Fe2—C4—C5 | 119.6 (4) |
C5i—Fe2—C1—C2 | −61.4 (4) | C3i—Fe2—C4—C5 | −60.4 (4) |
C4—Fe2—C1—C2 | 81.5 (3) | C2—Fe2—C4—C5 | 82.0 (3) |
C4i—Fe2—C1—C2 | −98.5 (3) | C2i—Fe2—C4—C5 | −98.0 (3) |
C1i—Fe2—C1—C2 | −51 (100) | C5—Fe2—C4—C3 | −119.6 (4) |
C3—Fe2—C1—C2 | 38.2 (3) | C5i—Fe2—C4—C3 | 60.4 (4) |
C3i—Fe2—C1—C2 | −141.8 (3) | C4i—Fe2—C4—C3 | −102 (100) |
C2i—Fe2—C1—C2 | 180.0 | C1—Fe2—C4—C3 | −81.5 (3) |
C5i—Fe2—C1—C5 | 180.0 | C1i—Fe2—C4—C3 | 98.5 (3) |
C4—Fe2—C1—C5 | −37.1 (3) | C3i—Fe2—C4—C3 | 180.0 |
C4i—Fe2—C1—C5 | 142.9 (3) | C2—Fe2—C4—C3 | −37.6 (3) |
C1i—Fe2—C1—C5 | −170 (100) | C2i—Fe2—C4—C3 | 142.4 (3) |
C3—Fe2—C1—C5 | −80.3 (3) | C3—C4—C5—C1 | 0.0 (5) |
C3i—Fe2—C1—C5 | 99.7 (3) | Fe2—C4—C5—C1 | −59.6 (3) |
C2—Fe2—C1—C5 | −118.6 (4) | C3—C4—C5—Fe2 | 59.6 (3) |
C2i—Fe2—C1—C5 | 61.4 (4) | C2—C1—C5—C4 | 0.3 (5) |
C5—Fe2—C1—C6 | −120.8 (5) | C6—C1—C5—C4 | −175.9 (4) |
C5i—Fe2—C1—C6 | 59.2 (5) | Fe2—C1—C5—C4 | 59.9 (3) |
C4—Fe2—C1—C6 | −157.9 (5) | C2—C1—C5—Fe2 | −59.6 (3) |
C4i—Fe2—C1—C6 | 22.1 (5) | C6—C1—C5—Fe2 | 124.3 (4) |
C1i—Fe2—C1—C6 | 69 (100) | C5i—Fe2—C5—C4 | −170 (100) |
C3—Fe2—C1—C6 | 158.9 (5) | C4i—Fe2—C5—C4 | 180.0 |
C3i—Fe2—C1—C6 | −21.1 (5) | C1—Fe2—C5—C4 | −119.4 (4) |
C2—Fe2—C1—C6 | 120.7 (5) | C1i—Fe2—C5—C4 | 60.6 (4) |
C2i—Fe2—C1—C6 | −59.3 (5) | C3—Fe2—C5—C4 | −37.2 (3) |
C5—C1—C2—C3 | −0.4 (5) | C3i—Fe2—C5—C4 | 142.8 (3) |
C6—C1—C2—C3 | 175.8 (4) | C2—Fe2—C5—C4 | −81.4 (3) |
Fe2—C1—C2—C3 | −59.5 (3) | C2i—Fe2—C5—C4 | 98.6 (3) |
C5—C1—C2—Fe2 | 59.1 (3) | C5i—Fe2—C5—C1 | −50 (100) |
C6—C1—C2—Fe2 | −124.7 (4) | C4—Fe2—C5—C1 | 119.4 (4) |
C5—Fe2—C2—C1 | −38.4 (3) | C4i—Fe2—C5—C1 | −60.6 (4) |
C5i—Fe2—C2—C1 | 141.6 (3) | C1i—Fe2—C5—C1 | 180.0 |
C4—Fe2—C2—C1 | −81.6 (3) | C3—Fe2—C5—C1 | 82.1 (3) |
C4i—Fe2—C2—C1 | 98.4 (3) | C3i—Fe2—C5—C1 | −97.9 (3) |
C1i—Fe2—C2—C1 | 180.0 | C2—Fe2—C5—C1 | 38.0 (3) |
C3—Fe2—C2—C1 | −118.5 (4) | C2i—Fe2—C5—C1 | −142.0 (3) |
C3i—Fe2—C2—C1 | 61.5 (4) | Si1—O1—C6—C7 | 58.0 (5) |
C2i—Fe2—C2—C1 | 22 (100) | Si1—O1—C6—C1 | 174.9 (3) |
C5—Fe2—C2—C3 | 80.1 (3) | Si1—O1—C6—C8 | −64.7 (5) |
C5i—Fe2—C2—C3 | −99.9 (3) | C2—C1—C6—O1 | 30.2 (6) |
C4—Fe2—C2—C3 | 36.9 (3) | C5—C1—C6—O1 | −154.4 (4) |
C4i—Fe2—C2—C3 | −143.1 (3) | Fe2—C1—C6—O1 | −62.5 (5) |
C1—Fe2—C2—C3 | 118.5 (4) | C2—C1—C6—C7 | 148.7 (4) |
C1i—Fe2—C2—C3 | −61.5 (4) | C5—C1—C6—C7 | −35.9 (6) |
C3i—Fe2—C2—C3 | 180.0 | Fe2—C1—C6—C7 | 56.0 (5) |
C2i—Fe2—C2—C3 | 140 (100) | C2—C1—C6—C8 | −92.2 (5) |
C1—C2—C3—C4 | 0.4 (5) | C5—C1—C6—C8 | 83.2 (5) |
Fe2—C2—C3—C4 | −59.2 (3) | Fe2—C1—C6—C8 | 175.1 (3) |
C1—C2—C3—Fe2 | 59.6 (3) | O1—C6—C7—N1 | 137 (29) |
C5—Fe2—C3—C4 | 37.2 (3) | C1—C6—C7—N1 | 19 (29) |
C5i—Fe2—C3—C4 | −142.8 (3) | C8—C6—C7—N1 | −99 (29) |
C4i—Fe2—C3—C4 | 180.0 | O1—C6—C8—C13 | 131.0 (5) |
C1—Fe2—C3—C4 | 81.8 (3) | C7—C6—C8—C13 | 8.5 (6) |
C1i—Fe2—C3—C4 | −98.2 (3) | C1—C6—C8—C13 | −109.0 (5) |
C3i—Fe2—C3—C4 | 127 (100) | O1—C6—C8—C9 | −50.2 (6) |
C2—Fe2—C3—C4 | 119.9 (4) | C7—C6—C8—C9 | −172.7 (4) |
C2i—Fe2—C3—C4 | −60.1 (4) | C1—C6—C8—C9 | 69.9 (5) |
C5—Fe2—C3—C2 | −82.7 (3) | C13—C8—C9—C10 | −1.2 (7) |
C5i—Fe2—C3—C2 | 97.3 (3) | C6—C8—C9—C10 | 179.9 (4) |
C4—Fe2—C3—C2 | −119.9 (4) | C8—C9—C10—C11 | 0.1 (8) |
C4i—Fe2—C3—C2 | 60.1 (4) | C14—O2—C11—C12 | −1.0 (8) |
C1—Fe2—C3—C2 | −38.1 (3) | C14—O2—C11—C10 | 178.6 (5) |
C1i—Fe2—C3—C2 | 141.9 (3) | C9—C10—C11—O2 | −177.9 (5) |
C3i—Fe2—C3—C2 | 7 (100) | C9—C10—C11—C12 | 1.8 (7) |
C2i—Fe2—C3—C2 | 180.0 | O2—C11—C12—C13 | 177.2 (5) |
C2—C3—C4—C5 | −0.2 (5) | C10—C11—C12—C13 | −2.4 (8) |
Fe2—C3—C4—C5 | −59.3 (3) | C9—C8—C13—C12 | 0.5 (7) |
C2—C3—C4—Fe2 | 59.1 (3) | C6—C8—C13—C12 | 179.4 (4) |
C5i—Fe2—C4—C5 | 180.0 | C11—C12—C13—C8 | 1.3 (8) |
Symmetry code: (i) −x+2, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | [Fe(C17H20NO2Si)2] |
Mr | 652.71 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 7.129 (2), 10.500 (4), 11.449 (4) |
α, β, γ (°) | 95.613 (5), 97.253 (6), 97.441 (6) |
V (Å3) | 837.3 (5) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.56 |
Crystal size (mm) | 0.24 × 0.14 × 0.12 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.822, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4803, 3367, 2156 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.063, 0.204, 1.03 |
No. of reflections | 3367 |
No. of parameters | 196 |
No. of restraints | 21 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.98, −0.43 |
Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2000).
Acknowledgements
The authors thank the National Natural Science Foundation of China (grant No. 20062004) for financial support.
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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.
Cyanohydrin trimethylsilyl ethers are useful in organic synthesis as they serve not only for the protection of carbonyl groups (Rasmussen et al., 1978; Groutas et al., 1980; Fischer et al., 1987) but also as versatile intermediates (Gassman et al., 1978; Evans et al., 1974; Fleming et al., 1979) in the synthesis of cyanohydrins, α,β-unsaturated nitriles and β-aminoalcohols. The general method for the preparation of cyanohydrin trimethylsilyl ethers is the addition of trimethylsilyl cyanide (TMSCN) to carbonyl compounds with the aid of a catalyst including Lewis acids, such as ZnI2 (Evans et al.,1974) and AlCl3 (Lidy et al., 1973), as well as solubilized anionic species, such as K+CN--18-Crown-6 and nBu4N+CN- (Evans et al.,1973).
The molecular structure of the title compound, (I), shows the Fe atom on a crystallographic center of inversion and two Cp ligands with a cyanohydrin ether substituents. Because of the inversion symmetry the Cp ligands show a staggered conformation. The central tetrahedral C(6) atom is bound to C≡N, (CH3)3SiO and (CH3O)C6H4 groups in compound and is therefore a new stereogenic center which is formed during the reaction sequence. Due to the internal symmetry of the molecule Figure 1 shows the R,S diastereomer. There is no evidence for the formation of R,R- or S,S-diastereomers even from NMR spectra of the crude reaction product. The bond angle of C(6)–C(7)–N(1) is 178.9 (6)° showing sp hybridization for the C≡N carbon atom. The Si(1)—O(1)—C(6) bond angle measures to 131.6 (3)° which is significantly larger compared to that of a regular tetrahedron (109.5°). The influence of neighbouring Csp and Csp2 atoms shorten the C(6)–C(1), C(6)–C(7) and C(6)–C(8) bond distances (1.511 (6) Å, 1.483 (7) Å and 1.531 (6), respectively) compared to normal C—C bond distances (app. 1.54 Å). It shows there may be a super conjugate effect in the molecule of the title compound.