organic compounds
Di-tert-butyl 3,3′-(2,2′-bi-1H-imidazole-1,1′-diyl)dipropanoate
aState Key Laboratory Base of Novel Functional Materials, and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, People's Republic of China
*Correspondence e-mail: lianghongze@nbu.edu.cn
In the title compound, C20H20N4O4, the complete molecule is generated by a crystallographic centre of symmetry. The conformation is stabilized by two intramolecular C—H⋯N links.
Related literature
For the background to 2, 2′-biimidazole derivatives, see: Barnett et al. (1999, 2002); Liang et al. (2009); Zhang & Liang (2009); Zhang, Zhang, Ren et al. (2009); Zhang, Zhang, Xu et al. (2009). For the synthesis, see: Barnett et al. (1999).
Experimental
Crystal data
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Refinement
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Data collection: RAPID-AUTO (Rigaku, 1998); cell RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536809021369/fb2148sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809021369/fb2148Isup2.hkl
The title compound was prepared according to a published procedure (Barnett et al., 1999). 0.2 g (5 mmol) of NaOH was added to a suspension of 3 g (22.4 mmol) of 2,2'-biimidazole in 100 ml of DMF (dimethylformamide) at 80°C. The resulting mixture was stirrred for 30 min. In the course of this time the mixture gradually turned into a clear pale yellow solution. 7.12 g (55.6 mmol) butyl acrylate in 10 ml of DMF was added dropwise in several minutes to the solution and the reaction was stirred at 80°C for 8 h until the heating was stopped. The DMF was removed via vacuum distillation in a hot oil bath at 100°C. The resulting black brown oil was dissolved in water (30 ml) and extracted with CH2Cl2. The organic layer was washed with water, and then evaporated under reduced pressure to yield a white product (7.4 g, 85%). The product was dissolved in 95% ethanol (30 ml) and cooled slowly in a refrigerator to afford colourless block crystals of average size 1.5 mm×1.2 mm×0.5 mm that were suitable for the X-ray analysis.
All the hydrogens were discernible in the difference
Nevertheless, the hydrogens were situated into the idealized positions. The C-H distances were constrained to 0.93, 0.96 and 0.97 Å for aryl, methylene and methyl hydrogens, respectively. Uiso(H) = 1.2 Ueq(Caryl); Uiso(H) = 1.2 Ueq(Cmethylene); Uiso(H) = 1.5 Ueq(Cmethyl).Data collection: RAPID-AUTO (Rigaku, 1998); cell
RAPID-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C20H30N4O4 | F(000) = 420 |
Mr = 390.48 | Dx = 1.197 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1478 reflections |
a = 7.0321 (14) Å | θ = 3.0–27.5° |
b = 17.484 (4) Å | µ = 0.08 mm−1 |
c = 8.9681 (18) Å | T = 295 K |
β = 100.80 (3)° | Plate, colourless |
V = 1083.1 (4) Å3 | 0.48 × 0.42 × 0.14 mm |
Z = 2 |
Rigaku R-AXIS RAPID diffractometer | 2453 independent reflections |
Radiation source: fine-focus sealed tube | 1474 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.077 |
Detector resolution: 0 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −22→22 |
Tmin = 0.960, Tmax = 0.988 | l = −11→10 |
9620 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)] = 0.077 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.190 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0718P)2 + 0.3943P] where P = (Fo2 + 2Fc2)/3 |
2453 reflections | (Δ/σ)max < 0.001 |
128 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
59 constraints |
C20H30N4O4 | V = 1083.1 (4) Å3 |
Mr = 390.48 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.0321 (14) Å | µ = 0.08 mm−1 |
b = 17.484 (4) Å | T = 295 K |
c = 8.9681 (18) Å | 0.48 × 0.42 × 0.14 mm |
β = 100.80 (3)° |
Rigaku R-AXIS RAPID diffractometer | 2453 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 1474 reflections with I > 2σ(I) |
Tmin = 0.960, Tmax = 0.988 | Rint = 0.077 |
9620 measured reflections |
R[F2 > 2σ(F2)] = 0.077 | 0 restraints |
wR(F2) = 0.190 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.32 e Å−3 |
2453 reflections | Δρmin = −0.24 e Å−3 |
128 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 | ||
N1 | 0.3460 (3) | 0.51573 (11) | 0.30746 (19) | 0.0410 (5) | |
N2 | 0.6689 (3) | 0.51901 (13) | 0.3698 (2) | 0.0522 (6) | |
C10 | 0.1400 (3) | 0.50398 (14) | 0.3101 (3) | 0.0454 (6) | |
H10A | 0.0628 | 0.5297 | 0.2237 | 0.054* | |
H10B | 0.1099 | 0.5268 | 0.4016 | 0.054* | |
O2 | 0.2468 (3) | 0.32667 (12) | 0.1854 (2) | 0.0717 (6) | |
O1 | 0.0366 (3) | 0.40123 (12) | 0.0365 (2) | 0.0774 (7) | |
C9 | 0.5051 (3) | 0.50815 (13) | 0.4210 (2) | 0.0415 (6) | |
C8 | 0.1171 (4) | 0.38275 (15) | 0.1612 (3) | 0.0525 (6) | |
C7 | 0.6104 (4) | 0.53329 (17) | 0.2169 (3) | 0.0568 (7) | |
H7A | 0.6939 | 0.5428 | 0.1501 | 0.068* | |
C6 | 0.4159 (4) | 0.53160 (15) | 0.1774 (2) | 0.0504 (6) | |
H6A | 0.3431 | 0.5396 | 0.0809 | 0.061* | |
C5 | 0.0864 (4) | 0.41992 (15) | 0.3056 (3) | 0.0520 (6) | |
H5A | 0.1644 | 0.3940 | 0.3914 | 0.062* | |
H5B | −0.0484 | 0.4147 | 0.3144 | 0.062* | |
C4 | 0.2854 (6) | 0.2868 (2) | 0.0492 (4) | 0.0905 (11) | |
H4A | 0.3139 | 0.3238 | −0.0242 | 0.109* | |
H4B | 0.1724 | 0.2577 | 0.0027 | 0.109* | |
C3 | 0.4524 (6) | 0.2349 (2) | 0.0943 (5) | 0.0958 (12) | |
H3A | 0.4239 | 0.2005 | 0.1722 | 0.115* | |
H3B | 0.4664 | 0.2039 | 0.0072 | 0.115* | |
C2 | 0.6387 (6) | 0.2728 (2) | 0.1520 (5) | 0.1045 (13) | |
H2B | 0.6290 | 0.3010 | 0.2434 | 0.125* | |
H2C | 0.6653 | 0.3092 | 0.0770 | 0.125* | |
C1 | 0.8074 (6) | 0.2163 (3) | 0.1876 (7) | 0.1289 (18) | |
H1A | 0.9241 | 0.2435 | 0.2285 | 0.193* | |
H1B | 0.8229 | 0.1904 | 0.0962 | 0.193* | |
H1C | 0.7809 | 0.1795 | 0.2605 | 0.193* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0380 (10) | 0.0516 (11) | 0.0319 (9) | 0.0030 (9) | 0.0030 (7) | 0.0023 (8) |
N2 | 0.0407 (11) | 0.0834 (16) | 0.0336 (10) | 0.0013 (10) | 0.0097 (8) | 0.0031 (10) |
C10 | 0.0364 (11) | 0.0564 (15) | 0.0413 (12) | 0.0045 (11) | 0.0017 (9) | 0.0019 (10) |
O2 | 0.0728 (13) | 0.0805 (15) | 0.0564 (12) | 0.0151 (11) | −0.0018 (9) | −0.0074 (10) |
O1 | 0.0988 (16) | 0.0791 (15) | 0.0457 (11) | 0.0097 (12) | −0.0087 (10) | 0.0001 (9) |
C9 | 0.0377 (11) | 0.0553 (14) | 0.0304 (11) | 0.0037 (11) | 0.0033 (8) | −0.0010 (9) |
C8 | 0.0518 (14) | 0.0532 (15) | 0.0491 (15) | −0.0082 (12) | 0.0006 (11) | 0.0019 (11) |
C7 | 0.0522 (15) | 0.086 (2) | 0.0343 (12) | −0.0015 (13) | 0.0134 (10) | 0.0047 (12) |
C6 | 0.0539 (14) | 0.0675 (17) | 0.0289 (11) | 0.0016 (12) | 0.0051 (10) | 0.0033 (11) |
C5 | 0.0474 (13) | 0.0629 (16) | 0.0444 (13) | −0.0046 (12) | 0.0054 (10) | 0.0044 (12) |
C4 | 0.100 (3) | 0.098 (3) | 0.069 (2) | 0.020 (2) | 0.0058 (18) | −0.0199 (19) |
C3 | 0.097 (3) | 0.095 (3) | 0.098 (3) | −0.005 (2) | 0.026 (2) | −0.021 (2) |
C2 | 0.101 (3) | 0.095 (3) | 0.115 (3) | −0.006 (2) | 0.013 (2) | −0.001 (2) |
C1 | 0.087 (3) | 0.101 (3) | 0.198 (5) | 0.000 (2) | 0.025 (3) | 0.031 (3) |
N1—C9 | 1.371 (3) | C6—H6A | 0.9300 |
N1—C6 | 1.376 (3) | C5—H5A | 0.9700 |
N1—C10 | 1.468 (3) | C5—H5B | 0.9700 |
N2—C9 | 1.331 (3) | C4—C3 | 1.480 (5) |
N2—C7 | 1.378 (3) | C4—H4A | 0.9700 |
C10—C5 | 1.516 (3) | C4—H4B | 0.9700 |
C10—H10A | 0.9700 | C3—C2 | 1.473 (5) |
C10—H10B | 0.9700 | C3—H3A | 0.9700 |
O2—C8 | 1.329 (3) | C3—H3B | 0.9700 |
O2—C4 | 1.475 (4) | C2—C1 | 1.531 (5) |
O1—C8 | 1.199 (3) | C2—H2B | 0.9700 |
C9—C9i | 1.460 (4) | C2—H2C | 0.9700 |
C8—C5 | 1.500 (4) | C1—H1A | 0.9600 |
C7—C6 | 1.347 (3) | C1—H1B | 0.9600 |
C7—H7A | 0.9300 | C1—H1C | 0.9600 |
C9—N1—C6 | 106.13 (18) | C10—C5—H5B | 109.3 |
C9—N1—C10 | 130.15 (19) | H5A—C5—H5B | 108.0 |
C6—N1—C10 | 123.53 (18) | O2—C4—C3 | 108.9 (3) |
C9—N2—C7 | 104.6 (2) | O2—C4—H4A | 109.9 |
N1—C10—C5 | 112.1 (2) | C3—C4—H4A | 109.9 |
N1—C10—H10A | 109.2 | O2—C4—H4B | 109.9 |
C5—C10—H10A | 109.2 | C3—C4—H4B | 109.9 |
N1—C10—H10B | 109.2 | H4A—C4—H4B | 108.3 |
C5—C10—H10B | 109.2 | C2—C3—C4 | 115.3 (4) |
H10A—C10—H10B | 107.9 | C2—C3—H3A | 108.4 |
C8—O2—C4 | 116.1 (2) | C4—C3—H3A | 108.4 |
N2—C9—N1 | 111.59 (19) | C2—C3—H3B | 108.4 |
N2—C9—C9i | 124.5 (2) | C4—C3—H3B | 108.4 |
N1—C9—C9i | 123.9 (2) | H3A—C3—H3B | 107.5 |
O1—C8—O2 | 122.7 (3) | C3—C2—C1 | 112.7 (4) |
O1—C8—C5 | 124.7 (3) | C3—C2—H2B | 109.0 |
O2—C8—C5 | 112.6 (2) | C1—C2—H2B | 109.0 |
C6—C7—N2 | 110.9 (2) | C3—C2—H2C | 109.0 |
C6—C7—H7A | 124.5 | C1—C2—H2C | 109.0 |
N2—C7—H7A | 124.5 | H2B—C2—H2C | 107.8 |
C7—C6—N1 | 106.7 (2) | C2—C1—H1A | 109.5 |
C7—C6—H6A | 126.6 | C2—C1—H1B | 109.5 |
N1—C6—H6A | 126.6 | H1A—C1—H1B | 109.5 |
C8—C5—C10 | 111.6 (2) | C2—C1—H1C | 109.5 |
C8—C5—H5A | 109.3 | H1A—C1—H1C | 109.5 |
C10—C5—H5A | 109.3 | H1B—C1—H1C | 109.5 |
C8—C5—H5B | 109.3 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
C10—H10B···N2i | 0.97 | 2.46 | 2.960 (3) | 111 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C20H30N4O4 |
Mr | 390.48 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 295 |
a, b, c (Å) | 7.0321 (14), 17.484 (4), 8.9681 (18) |
β (°) | 100.80 (3) |
V (Å3) | 1083.1 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.48 × 0.42 × 0.14 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.960, 0.988 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9620, 2453, 1474 |
Rint | 0.077 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.077, 0.190, 1.02 |
No. of reflections | 2453 |
No. of parameters | 128 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.32, −0.24 |
Computer programs: RAPID-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C10—H10B···N2i | 0.97 | 2.46 | 2.960 (3) | 111 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Acknowledgements
This project was sponsored by the Scientific Research Foundation of the State Education Ministry for Returned Overseas Chinese Scholars (2006701), the Critical Projects in Science and Technology Department of Zhejiang Province (2007 C21113), the Education Committee of Zhejiang Province (20061696, 2008934), the Natural Science Foundation of Ningbo City (2007 A610021) and the K. C. Wong Magna Fund of Ningbo University. We thank Professor X. Li for helpful discussions about the
and Mr W. Xu for collecting the crystal data.References
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Biimidazole is a potentially polydentate ligand, but its chemistry is less developed in comparison to the imidazole chemistry. The reason may be a limited solubility of biimidazole in common organic solvents. Although several new disubstituted 2,2'-biimidazoles have been recently synthesized (Barnett et al., 1999; Barnett et al., 2002), a few metal complexes based on biimidazole derivatives are reported (Zhang, Zhang, Ren et al., 2009). In the course of our ongoing study, we have successfully synthesized a series of biimidazole derivatives with terminal carboxylic, hydroxyl, phosphino, imino groups which can be used as ligands in the coordination chemistry (Zhang & Liang, 2009; Zhang, Zhang, Xu et al., 2009) and cross-coupling reactions (Liang et al., 2009). These ligands exhibit rich coordination patterns and catalytic properties. Here we report the synthesis and the crystal structure of the title compound which is an intermediate of those above mentioned ligands. As shown in Fig. 1, the biimidazole ring atoms (C6, C7, C9, N1, N2 and their inversion-related partners) exhibit essentially coplanar mutual orientation [the dihedral angle is 0.00 (1)°], and the value of the torsion angle C9—N1—C10—C5 is -77.53 (30)°. In the crystal structure, there are weak C-H···N interactions (Tab. 1, Fig. 2).