organic compounds
rac-(E,E)-N,N′-Bis(2-chlorobenzylidene)cyclohexane-1,2-diamine
aDepartment of Chemistry, An-Najah National University, Nablus, Palestinian Territories, bDepartment of Chemistry, Hashemite University, Zarqa 13115, Jordan, cDepartment of Chemistry, University of Jordan, Amman 11942, Jordan, and dLCAE-URAC18, Faculté des Sciences, Université Mohammed Ier, Oujda 60000, Morocco
*Correspondence e-mail: i.kh.warad@gmail.com, manoaimi@hu.edu.jo
In the title racemic Schiff base ligand, C20H20Cl2N2, which was prepared by the condensation of 2-chlorobenzaldehyde and cyclohexane-1,2-diamine, the cyclohexane ring adopts a chair conformation and the dihedral angle between the aromatic rings of the 2-chlorophenyl substituent groups is 62.52 (8)°. In the structure, there are two short intramolecular methine C—H⋯Cl interactions [C⋯Cl = 3.066 (2) and 3.076 (3) Å], and in the crystal there are also weak intermolecular aromatic C—H⋯Cl [3.464 (3), 3.553 (3) and 3.600 (3) Å] and Cl⋯Cl [3.557 (3) and 3.891 (3) Å] contacts.
Related literature
For the crystal structures of some et al. (2012); Fan et al. (2011); Saleh Salga et al. (2010). For applications of chiral Schiff base ligands, see: Da Silva et al. (2011); Dhar & Taploo (1982); Przybylski et al. (2009); Gupta & Sutar (2008). For the synthesis of the title compound, see: Larrow & Jacobsen (1998).
derived from cyclohexane-1,2-diamine, see: ArvinnezhadExperimental
Crystal data
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Data collection: CrysAlis PRO (Agilent, 2011); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536813014554/zs2261sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813014554/zs2261Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813014554/zs2261Isup3.cml
(R,R)-1,2-Diaminocyclohexane (1 g, 8.9 mmol) was dissolved in EtOH (10 ml) and the mixture was stirred and heated gently (50 °C) for 10 min, after which a solution of 2-chlorobenzaldehyde (2.6 g, 18 mmol, 2 equivalents) in EtOH (5 ml) was added dropwise. The stirred reaction mixture was refluxed for a period of 4 h, with the reaction progress monitored by
Upon completion of the reaction, the mixture was cooled to room temperature and the solid obtained was filtered off, washed with cold water and crystallized from ethanol (95%), with a 85% yield.H atoms were positioned geometrically with C—H = 0.93 Å (aromatic), 0.97 Å (methylene) or 0.98 Å (methine) and allowed to ride in the
with Uiso(H) = 1.2Ueq(C). The largest difference peak and hole are 0.276 and -0.204 e Å-3.The chelating chiral
are significant compounds in chemistry so that several reviews have been published on these substances (Gupta & Sutar, 2008; Da Silva et al., 2011; Przybylski et al., 2009). Because of their stereochemical features, as well as their industrial properties (Dhar & Taploo, 1982) and potent biological activities (Da Silva et al., 2011; Przybylski et al., 2009), they are very attractive synthetic targets. Furthermore, it should be stressed that these useful and recyclable chemicals have been widely used in various enantioselective reactions, such as cyclopropanation, aziridination, epoxidation or the Diels–Alder reaction, and as ligands or catalysts.The title Schiff base, C20H20Cl2N2, was prepared by condensation of commercially available 2-chlorobenzaldehyde and (1R,2R)-diaminocyclohexane and the structure is reported herein. However, this compound is racemic, in which the cyclohexane ring adopts the expected chair conformation, with a dihedral angle of 62.52 (8)° between the aromatic rings of the two 2-chlorophenyl substituent groups (Fig. 1). The structure of the chiral isomeric (1R,2R) 4-chlorophenyl analogue has been reported (Arvinnezhad et al., 2012). In the title compound, the conformation is stabilized by intramolecular C7—H···Cl1 and C14—H··· Cl2 interactions [3.066 (2) and 3.076 (3) Å, respectively] (Table 1). In the crystal there are weak intermolecular methine C—H···Cl interactions [C10—H···Cl1 [3.600 (3) Å] (-x + 2, -y, -z), C11—H···Cl1 [3.553 (3) Å] (x - 1, y, z) and C20—H···Cl2 [3.464 (3) Å] (1 + x + 1, y, z). Also present in the crystal are Cl···Cl contacts [Cl1···Cl1, 3.557 (3) Å (-x + 1, -y, -z)] and 3.891 (3) Å (-x + 2, -y, -z) (Fig. 2).
For the crystal structures of some
derived from cyclohexane-1,2-diamine, see: Arvinnezhad et al. (2012); Fan et al. (2011); Saleh Salga et al. (2010). For applications of chiral Schiff base ligands, see: Da Silva et al. (2011); Dhar & Taploo (1982); Przybylski et al. (2009); Gupta & Sutar (2008). For the synthesis of the title compound, see: Larrow & Jacobsen (1998).Data collection: CrysAlis PRO (Agilent, 2011); cell
CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C20H20Cl2N2 | F(000) = 752 |
Mr = 359.28 | Dx = 1.281 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 2442 reflections |
a = 5.9029 (5) Å | θ = 3.1–29.1° |
b = 19.5613 (13) Å | µ = 0.35 mm−1 |
c = 16.1662 (11) Å | T = 293 K |
β = 93.493 (7)° | Block, colourless |
V = 1863.2 (2) Å3 | 0.30 × 0.20 × 0.15 mm |
Z = 4 |
Agilent Xcalibur Eos diffractometer | 3273 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 2252 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
Detector resolution: 16.0534 pixels mm-1 | θmax = 25.0°, θmin = 3.3° |
ω scans | h = −7→6 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | k = −23→18 |
Tmin = 0.902, Tmax = 0.949 | l = −19→17 |
7483 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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.106 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.0349P)2 + 0.4202P] where P = (Fo2 + 2Fc2)/3 |
3273 reflections | (Δ/σ)max < 0.001 |
217 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C20H20Cl2N2 | V = 1863.2 (2) Å3 |
Mr = 359.28 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 5.9029 (5) Å | µ = 0.35 mm−1 |
b = 19.5613 (13) Å | T = 293 K |
c = 16.1662 (11) Å | 0.30 × 0.20 × 0.15 mm |
β = 93.493 (7)° |
Agilent Xcalibur Eos diffractometer | 3273 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | 2252 reflections with I > 2σ(I) |
Tmin = 0.902, Tmax = 0.949 | Rint = 0.030 |
7483 measured reflections |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.106 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.28 e Å−3 |
3273 reflections | Δρmin = −0.20 e Å−3 |
217 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 | ||
Cl1 | 0.73684 (13) | 0.05324 (3) | 0.02770 (4) | 0.0762 (2) | |
Cl2 | 1.12436 (13) | 0.46542 (4) | 0.17646 (5) | 0.0914 (3) | |
N1 | 0.7836 (3) | 0.26396 (10) | −0.03727 (11) | 0.0555 (5) | |
C8 | 0.9564 (4) | 0.17516 (12) | 0.04725 (12) | 0.0489 (6) | |
C1 | 0.5739 (4) | 0.29405 (11) | −0.07382 (12) | 0.0520 (6) | |
H1B | 0.4442 | 0.2674 | −0.0567 | 0.062* | |
C6 | 0.5559 (4) | 0.36693 (12) | −0.04157 (13) | 0.0583 (7) | |
H6A | 0.6885 | 0.3932 | −0.0568 | 0.070* | |
N2 | 0.5510 (4) | 0.36480 (10) | 0.04896 (11) | 0.0613 (6) | |
C14 | 0.7170 (5) | 0.39062 (12) | 0.09007 (14) | 0.0586 (6) | |
H14A | 0.8318 | 0.4110 | 0.0617 | 0.070* | |
C7 | 0.7660 (4) | 0.20790 (12) | −0.00033 (12) | 0.0492 (6) | |
H7A | 0.6258 | 0.1861 | −0.0032 | 0.059* | |
C13 | 1.1395 (4) | 0.21396 (13) | 0.07903 (13) | 0.0587 (6) | |
H13A | 1.1465 | 0.2602 | 0.0661 | 0.070* | |
C15 | 0.7373 (4) | 0.38992 (12) | 0.18143 (14) | 0.0550 (6) | |
C10 | 1.1237 (5) | 0.07662 (14) | 0.11857 (14) | 0.0673 (8) | |
H10A | 1.1179 | 0.0304 | 0.1317 | 0.081* | |
C9 | 0.9546 (4) | 0.10611 (12) | 0.06799 (12) | 0.0540 (6) | |
C16 | 0.9153 (4) | 0.42153 (12) | 0.22641 (15) | 0.0615 (7) | |
C20 | 0.5769 (5) | 0.35715 (13) | 0.22604 (15) | 0.0669 (7) | |
H20A | 0.4546 | 0.3359 | 0.1976 | 0.080* | |
C11 | 1.3010 (5) | 0.11644 (17) | 0.14930 (15) | 0.0777 (9) | |
H11A | 1.4156 | 0.0972 | 0.1838 | 0.093* | |
C17 | 0.9323 (5) | 0.42009 (15) | 0.31214 (17) | 0.0756 (8) | |
H17A | 1.0535 | 0.4415 | 0.3411 | 0.091* | |
C2 | 0.5740 (4) | 0.29389 (13) | −0.16818 (13) | 0.0634 (7) | |
H2B | 0.7073 | 0.3178 | −0.1853 | 0.076* | |
H2C | 0.5804 | 0.2472 | −0.1880 | 0.076* | |
C3 | 0.3615 (5) | 0.32848 (13) | −0.20597 (14) | 0.0679 (7) | |
H3A | 0.3679 | 0.3298 | −0.2658 | 0.081* | |
H3B | 0.2292 | 0.3020 | −0.1931 | 0.081* | |
C5 | 0.3413 (5) | 0.40078 (14) | −0.07892 (15) | 0.0783 (9) | |
H5A | 0.3340 | 0.4476 | −0.0594 | 0.094* | |
H5B | 0.2093 | 0.3766 | −0.0610 | 0.094* | |
C12 | 1.3100 (4) | 0.18501 (17) | 0.12915 (15) | 0.0725 (8) | |
H12A | 1.4315 | 0.2116 | 0.1495 | 0.087* | |
C19 | 0.5930 (5) | 0.35511 (14) | 0.31149 (17) | 0.0783 (8) | |
H19A | 0.4841 | 0.3322 | 0.3401 | 0.094* | |
C4 | 0.3382 (5) | 0.40022 (14) | −0.17353 (16) | 0.0825 (9) | |
H4A | 0.1970 | 0.4199 | −0.1962 | 0.099* | |
H4B | 0.4620 | 0.4281 | −0.1915 | 0.099* | |
C18 | 0.7716 (6) | 0.38728 (15) | 0.35396 (17) | 0.0819 (9) | |
H18A | 0.7825 | 0.3866 | 0.4116 | 0.098* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0871 (5) | 0.0566 (4) | 0.0835 (5) | 0.0021 (4) | −0.0058 (4) | 0.0000 (3) |
Cl2 | 0.0686 (5) | 0.1026 (6) | 0.1027 (6) | −0.0136 (4) | 0.0018 (4) | −0.0098 (4) |
N1 | 0.0581 (13) | 0.0600 (13) | 0.0482 (11) | 0.0065 (10) | 0.0025 (10) | 0.0112 (9) |
C8 | 0.0547 (15) | 0.0576 (15) | 0.0350 (11) | 0.0102 (12) | 0.0076 (10) | −0.0003 (10) |
C1 | 0.0560 (15) | 0.0538 (14) | 0.0457 (12) | 0.0028 (12) | 0.0003 (11) | 0.0077 (10) |
C6 | 0.0690 (17) | 0.0549 (15) | 0.0499 (13) | 0.0001 (13) | −0.0050 (12) | 0.0039 (11) |
N2 | 0.0686 (14) | 0.0649 (13) | 0.0497 (11) | 0.0024 (11) | −0.0019 (10) | −0.0047 (9) |
C14 | 0.0677 (17) | 0.0493 (14) | 0.0583 (15) | 0.0044 (13) | 0.0002 (13) | −0.0018 (11) |
C7 | 0.0542 (14) | 0.0543 (14) | 0.0393 (11) | 0.0055 (12) | 0.0034 (10) | −0.0002 (11) |
C13 | 0.0649 (17) | 0.0636 (16) | 0.0478 (13) | 0.0032 (13) | 0.0052 (12) | −0.0007 (11) |
C15 | 0.0638 (16) | 0.0454 (14) | 0.0547 (14) | 0.0065 (12) | −0.0065 (13) | −0.0056 (11) |
C10 | 0.087 (2) | 0.0641 (17) | 0.0496 (14) | 0.0270 (16) | −0.0021 (14) | −0.0012 (12) |
C9 | 0.0653 (16) | 0.0589 (15) | 0.0376 (12) | 0.0145 (13) | 0.0024 (11) | −0.0025 (10) |
C16 | 0.0647 (17) | 0.0533 (15) | 0.0656 (16) | 0.0062 (13) | −0.0041 (13) | −0.0067 (12) |
C20 | 0.0782 (19) | 0.0636 (17) | 0.0576 (16) | −0.0079 (15) | −0.0060 (14) | −0.0053 (12) |
C11 | 0.081 (2) | 0.097 (2) | 0.0536 (15) | 0.0358 (18) | −0.0137 (15) | −0.0084 (15) |
C17 | 0.081 (2) | 0.076 (2) | 0.0680 (18) | 0.0003 (17) | −0.0157 (16) | −0.0181 (15) |
C2 | 0.0752 (18) | 0.0686 (17) | 0.0461 (13) | 0.0056 (14) | 0.0021 (13) | 0.0066 (12) |
C3 | 0.0817 (19) | 0.0721 (18) | 0.0481 (14) | 0.0024 (15) | −0.0103 (13) | 0.0079 (12) |
C5 | 0.096 (2) | 0.0648 (17) | 0.0712 (18) | 0.0260 (16) | −0.0146 (16) | −0.0042 (14) |
C12 | 0.0621 (17) | 0.098 (2) | 0.0570 (16) | 0.0101 (17) | −0.0040 (14) | −0.0143 (15) |
C19 | 0.095 (2) | 0.0727 (19) | 0.0674 (18) | −0.0071 (17) | 0.0074 (16) | 0.0016 (14) |
C4 | 0.100 (2) | 0.0716 (19) | 0.0717 (18) | 0.0166 (17) | −0.0243 (17) | 0.0146 (14) |
C18 | 0.111 (3) | 0.077 (2) | 0.0552 (16) | 0.0005 (19) | −0.0075 (18) | −0.0097 (14) |
Cl1—C9 | 1.745 (2) | C10—H10A | 0.9300 |
Cl2—C16 | 1.742 (3) | C16—C17 | 1.384 (3) |
N1—C7 | 1.256 (3) | C20—C19 | 1.379 (3) |
N1—C1 | 1.462 (3) | C20—H20A | 0.9300 |
C8—C9 | 1.392 (3) | C11—C12 | 1.382 (4) |
C8—C13 | 1.393 (3) | C11—H11A | 0.9300 |
C8—C7 | 1.469 (3) | C17—C18 | 1.359 (4) |
C1—C6 | 1.524 (3) | C17—H17A | 0.9300 |
C1—C2 | 1.525 (3) | C2—C3 | 1.520 (3) |
C1—H1B | 0.9800 | C2—H2B | 0.9700 |
C6—N2 | 1.466 (3) | C2—H2C | 0.9700 |
C6—C5 | 1.522 (3) | C3—C4 | 1.507 (4) |
C6—H6A | 0.9800 | C3—H3A | 0.9700 |
N2—C14 | 1.256 (3) | C3—H3B | 0.9700 |
C14—C15 | 1.475 (3) | C5—C4 | 1.529 (3) |
C14—H14A | 0.9300 | C5—H5A | 0.9700 |
C7—H7A | 0.9300 | C5—H5B | 0.9700 |
C13—C12 | 1.375 (3) | C12—H12A | 0.9300 |
C13—H13A | 0.9300 | C19—C18 | 1.375 (4) |
C15—C20 | 1.383 (3) | C19—H19A | 0.9300 |
C15—C16 | 1.386 (3) | C4—H4A | 0.9700 |
C10—C11 | 1.373 (4) | C4—H4B | 0.9700 |
C10—C9 | 1.378 (3) | C18—H18A | 0.9300 |
C7—N1—C1 | 116.8 (2) | C15—C20—H20A | 119.1 |
C9—C8—C13 | 117.2 (2) | C10—C11—C12 | 120.3 (2) |
C9—C8—C7 | 122.2 (2) | C10—C11—H11A | 119.9 |
C13—C8—C7 | 120.5 (2) | C12—C11—H11A | 119.9 |
N1—C1—C6 | 108.26 (18) | C18—C17—C16 | 119.8 (3) |
N1—C1—C2 | 110.58 (19) | C18—C17—H17A | 120.1 |
C6—C1—C2 | 110.38 (18) | C16—C17—H17A | 120.1 |
N1—C1—H1B | 109.2 | C3—C2—C1 | 110.5 (2) |
C6—C1—H1B | 109.2 | C3—C2—H2B | 109.5 |
C2—C1—H1B | 109.2 | C1—C2—H2B | 109.5 |
N2—C6—C5 | 110.0 (2) | C3—C2—H2C | 109.5 |
N2—C6—C1 | 108.72 (18) | C1—C2—H2C | 109.5 |
C5—C6—C1 | 110.19 (19) | H2B—C2—H2C | 108.1 |
N2—C6—H6A | 109.3 | C4—C3—C2 | 111.4 (2) |
C5—C6—H6A | 109.3 | C4—C3—H3A | 109.3 |
C1—C6—H6A | 109.3 | C2—C3—H3A | 109.3 |
C14—N2—C6 | 117.0 (2) | C4—C3—H3B | 109.3 |
N2—C14—C15 | 122.6 (3) | C2—C3—H3B | 109.3 |
N2—C14—H14A | 118.7 | H3A—C3—H3B | 108.0 |
C15—C14—H14A | 118.7 | C6—C5—C4 | 110.7 (2) |
N1—C7—C8 | 123.1 (2) | C6—C5—H5A | 109.5 |
N1—C7—H7A | 118.4 | C4—C5—H5A | 109.5 |
C8—C7—H7A | 118.4 | C6—C5—H5B | 109.5 |
C12—C13—C8 | 121.1 (3) | C4—C5—H5B | 109.5 |
C12—C13—H13A | 119.5 | H5A—C5—H5B | 108.1 |
C8—C13—H13A | 119.5 | C13—C12—C11 | 120.1 (3) |
C20—C15—C16 | 117.0 (2) | C13—C12—H12A | 119.9 |
C20—C15—C14 | 120.7 (2) | C11—C12—H12A | 119.9 |
C16—C15—C14 | 122.3 (3) | C18—C19—C20 | 119.4 (3) |
C11—C10—C9 | 119.1 (3) | C18—C19—H19A | 120.3 |
C11—C10—H10A | 120.5 | C20—C19—H19A | 120.3 |
C9—C10—H10A | 120.5 | C3—C4—C5 | 111.0 (2) |
C10—C9—C8 | 122.2 (2) | C3—C4—H4A | 109.4 |
C10—C9—Cl1 | 117.6 (2) | C5—C4—H4A | 109.4 |
C8—C9—Cl1 | 120.09 (17) | C3—C4—H4B | 109.4 |
C17—C16—C15 | 121.5 (3) | C5—C4—H4B | 109.4 |
C17—C16—Cl2 | 117.6 (2) | H4A—C4—H4B | 108.0 |
C15—C16—Cl2 | 120.8 (2) | C17—C18—C19 | 120.3 (3) |
C19—C20—C15 | 121.9 (2) | C17—C18—H18A | 119.8 |
C19—C20—H20A | 119.1 | C19—C18—H18A | 119.8 |
C7—N1—C1—C6 | 126.4 (2) | C20—C15—C16—C17 | 0.3 (4) |
C7—N1—C1—C2 | −112.5 (2) | C14—C15—C16—C17 | −179.7 (2) |
N1—C1—C6—N2 | −60.1 (3) | C20—C15—C16—Cl2 | −178.99 (19) |
C2—C1—C6—N2 | 178.69 (19) | C14—C15—C16—Cl2 | 1.0 (3) |
N1—C1—C6—C5 | 179.2 (2) | C16—C15—C20—C19 | −0.7 (4) |
C2—C1—C6—C5 | 58.1 (3) | C14—C15—C20—C19 | 179.3 (2) |
C5—C6—N2—C14 | −125.3 (2) | C9—C10—C11—C12 | −0.5 (4) |
C1—C6—N2—C14 | 114.0 (2) | C15—C16—C17—C18 | −0.2 (4) |
C6—N2—C14—C15 | −178.0 (2) | Cl2—C16—C17—C18 | 179.1 (2) |
C1—N1—C7—C8 | −173.03 (19) | N1—C1—C2—C3 | −177.1 (2) |
C9—C8—C7—N1 | −161.7 (2) | C6—C1—C2—C3 | −57.3 (3) |
C13—C8—C7—N1 | 23.4 (3) | C1—C2—C3—C4 | 56.3 (3) |
C9—C8—C13—C12 | −0.4 (3) | N2—C6—C5—C4 | −177.2 (2) |
C7—C8—C13—C12 | 174.8 (2) | C1—C6—C5—C4 | −57.3 (3) |
N2—C14—C15—C20 | 3.3 (4) | C8—C13—C12—C11 | −0.4 (4) |
N2—C14—C15—C16 | −176.7 (2) | C10—C11—C12—C13 | 0.9 (4) |
C11—C10—C9—C8 | −0.4 (4) | C15—C20—C19—C18 | 0.9 (4) |
C11—C10—C9—Cl1 | 178.1 (2) | C2—C3—C4—C5 | −55.8 (3) |
C13—C8—C9—C10 | 0.8 (3) | C6—C5—C4—C3 | 56.3 (3) |
C7—C8—C9—C10 | −174.3 (2) | C16—C17—C18—C19 | 0.5 (4) |
C13—C8—C9—Cl1 | −177.66 (17) | C20—C19—C18—C17 | −0.8 (4) |
C7—C8—C9—Cl1 | 7.3 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7A···Cl1 | 0.93 | 2.72 | 3.066 (2) | 103 |
C14—H14A···Cl2 | 0.93 | 2.68 | 3.076 (3) | 107 |
Experimental details
Crystal data | |
Chemical formula | C20H20Cl2N2 |
Mr | 359.28 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 5.9029 (5), 19.5613 (13), 16.1662 (11) |
β (°) | 93.493 (7) |
V (Å3) | 1863.2 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.35 |
Crystal size (mm) | 0.30 × 0.20 × 0.15 |
Data collection | |
Diffractometer | Agilent Xcalibur Eos |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2011) |
Tmin, Tmax | 0.902, 0.949 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7483, 3273, 2252 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.106, 1.02 |
No. of reflections | 3273 |
No. of parameters | 217 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.28, −0.20 |
Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996).
Acknowledgements
This project was supported by An-Najah National University and Hashemite University. The X-ray structural work was carried out at the Hamdi Mango Center for Scientific Research at the University of Jordan.
References
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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.
The chelating chiral Schiff bases are significant compounds in chemistry so that several reviews have been published on these substances (Gupta & Sutar, 2008; Da Silva et al., 2011; Przybylski et al., 2009). Because of their stereochemical features, as well as their industrial properties (Dhar & Taploo, 1982) and potent biological activities (Da Silva et al., 2011; Przybylski et al., 2009), they are very attractive synthetic targets. Furthermore, it should be stressed that these useful and recyclable chemicals have been widely used in various enantioselective reactions, such as cyclopropanation, aziridination, epoxidation or the Diels–Alder reaction, and as ligands or catalysts.
The title Schiff base, C20H20Cl2N2, was prepared by condensation of commercially available 2-chlorobenzaldehyde and (1R,2R)-diaminocyclohexane and the structure is reported herein. However, this compound is racemic, in which the cyclohexane ring adopts the expected chair conformation, with a dihedral angle of 62.52 (8)° between the aromatic rings of the two 2-chlorophenyl substituent groups (Fig. 1). The structure of the chiral isomeric (1R,2R) 4-chlorophenyl analogue has been reported (Arvinnezhad et al., 2012). In the title compound, the conformation is stabilized by intramolecular C7—H···Cl1 and C14—H··· Cl2 interactions [3.066 (2) and 3.076 (3) Å, respectively] (Table 1). In the crystal there are weak intermolecular methine C—H···Cl interactions [C10—H···Cl1 [3.600 (3) Å] (-x + 2, -y, -z), C11—H···Cl1 [3.553 (3) Å] (x - 1, y, z) and C20—H···Cl2 [3.464 (3) Å] (1 + x + 1, y, z). Also present in the crystal are Cl···Cl contacts [Cl1···Cl1, 3.557 (3) Å (-x + 1, -y, -z)] and 3.891 (3) Å (-x + 2, -y, -z) (Fig. 2).