organic compounds
cis-N1,N2-Bis(2-hydroxybenzylidene)cyclohexane-1,2-diamine
aCollege of Chemistry, Liaoning University, Shenyang, Liaoning 110036, People's Republic of China
*Correspondence e-mail: chhge@lnu.edu.cn
In the title compound, C20H22N2O2, the cyclohexane ring adopts a chair conformation and the two N atoms bonded to salicylidene groups are in cis positions. Both hydroxy groups are involved in intramolecular O—H⋯N hydrogen bonding and the two benzene rings form a dihedral angle of 60.5 (1)°.
Related literature
For the trans-N,N′-bis(salicylidene)-1,2-cyclohexanediamine, see: Cannadine et al. (1996); Liu et al. (1997), and for the crystal structures of its complexes, see: Khalaji et al. (2010); Man et al. (2008); Xu et al. (2009).
ofExperimental
Crystal data
|
Refinement
|
|
Data collection: SMART (Bruker, 2001); cell SAINT (Bruker, 2001); data reduction: SAINT; 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, PLATON (Spek, 2009) and WinGX (Farrugia, 1999).
Supporting information
https://doi.org/10.1107/S1600536811049038/cv5199sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811049038/cv5199Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536811049038/cv5199Isup3.cml
The cis-trans mixture of 1,2-cyclohexanediamine was purchased from Alfa Aesar and was used as received without further purification. The title compound was obtained as following: added 0.05 mol salicylaldehyde slowly to ethanol solution of 1,2-cyclohexanediamine with stirring, then the resulting mixture was stirred 2 h under reflexing. By slow evaporation, yellow block-shape single crystals suitable for X-ray analysis were obtained within several days.
All H atoms were placed in geometrically idealized positions (C—H = 0.93 - 0.97 Å, and O—H = 0.82 Å), and refined in a riding model, with Uiso(H) = 1.2-1.5 Ueq of the parent atom. In the absence of any significant anomalous scatterers in the molecule, the 1621 Friedel pairs were merged before the final refinement.
1,2-Cyclohexanediamine has trans-cis isomers, so their reaction products are also isomers. trans-N,N'-Bis(salicylidene)-1,2-cyclohexanediamine has been prepared and characterized via X-ray crystallography (Cannadine et al., 1996; Liu et al., 1997). The compound is current of interest due to its fascinating versatility as coordination ligand (Khalaji et al., 2010; Man et al., 2008; Xu et al., 2009). As cis-isomer is difficult to form complex, it has received relatively few studies.
The stucture of the title compound is shown in Fig. 1. The two N-salicylidene groups are cis in the structure with the same constitution but differ in the arrangement of their atoms in space. Dihedral angel between aromatic rings is 60.5 (1) °, between the ring of C1—C6 and C8/C10/C12 is 88.8 (1) °, between the ring of C15—C20 and C8/C10/C12 is 75.2 (1)°, respectively. hydroxy groups and imine groups are involved in intramolecular hydrogen bonding (Table 1).
For the
of trans-N,N'-bis(salicylidene)-1,2-cyclohexanediamine, see: Cannadine et al. (1996); Liu et al. (1997), and for the crystal structures of its complexes, see: Khalaji et al. (2010); Man et al. (2008); Xu et al. (2009).Data collection: SMART (Bruker, 2001); cell
SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); 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), PLATON (Spek, 2009) and WinGX (Farrugia, 1999).Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. |
C20H22N2O2 | F(000) = 688 |
Mr = 322.40 | Dx = 1.180 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 126 reflections |
a = 6.125 (3) Å | θ = 2.5–23.1° |
b = 13.763 (6) Å | µ = 0.08 mm−1 |
c = 21.537 (9) Å | T = 296 K |
V = 1815.4 (13) Å3 | Block, yellow |
Z = 4 | 0.25 × 0.15 × 0.12 mm |
Bruker SMART CCD area-detector diffractometer | 4195 independent reflections |
Radiation source: fine-focus sealed tube | 2178 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
φ and ω scans | θmax = 28.2°, θmin = 1.9° |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | h = −8→8 |
Tmin = 0.987, Tmax = 0.991 | k = −18→8 |
9439 measured reflections | l = −27→28 |
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)] = 0.044 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.115 | H-atom parameters constrained |
S = 0.99 | w = 1/[σ2(Fo2) + (0.0487P)2] where P = (Fo2 + 2Fc2)/3 |
4195 reflections | (Δ/σ)max < 0.001 |
219 parameters | Δρmax = 0.09 e Å−3 |
0 restraints | Δρmin = −0.10 e Å−3 |
C20H22N2O2 | V = 1815.4 (13) Å3 |
Mr = 322.40 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 6.125 (3) Å | µ = 0.08 mm−1 |
b = 13.763 (6) Å | T = 296 K |
c = 21.537 (9) Å | 0.25 × 0.15 × 0.12 mm |
Bruker SMART CCD area-detector diffractometer | 4195 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | 2178 reflections with I > 2σ(I) |
Tmin = 0.987, Tmax = 0.991 | Rint = 0.026 |
9439 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.115 | H-atom parameters constrained |
S = 0.99 | Δρmax = 0.09 e Å−3 |
4195 reflections | Δρmin = −0.10 e Å−3 |
219 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 | ||
N2 | −0.0052 (3) | 1.09660 (12) | 0.07839 (9) | 0.0732 (5) | |
N1 | −0.0383 (3) | 0.92191 (11) | 0.14663 (8) | 0.0654 (4) | |
C14 | −0.0964 (4) | 1.13716 (14) | 0.03205 (11) | 0.0692 (6) | |
H14 | −0.2311 | 1.1672 | 0.0374 | 0.083* | |
O1 | 0.3379 (3) | 0.84294 (11) | 0.17057 (9) | 0.0955 (5) | |
H1 | 0.2397 | 0.8833 | 0.1722 | 0.143* | |
C15 | 0.0042 (3) | 1.13768 (13) | −0.02904 (10) | 0.0622 (5) | |
C7 | −0.0724 (4) | 0.85231 (15) | 0.10808 (9) | 0.0642 (5) | |
H7 | −0.2020 | 0.8521 | 0.0856 | 0.077* | |
C13 | −0.1099 (4) | 1.09759 (15) | 0.13967 (10) | 0.0736 (6) | |
H13 | −0.2294 | 1.1449 | 0.1388 | 0.088* | |
C20 | 0.2131 (4) | 1.09706 (15) | −0.03864 (11) | 0.0699 (6) | |
O2 | 0.3257 (3) | 1.05667 (15) | 0.00898 (8) | 0.1061 (6) | |
H2 | 0.2520 | 1.0593 | 0.0407 | 0.159* | |
C8 | −0.2060 (3) | 0.99701 (14) | 0.15462 (9) | 0.0670 (6) | |
H8 | −0.3264 | 0.9838 | 0.1258 | 0.080* | |
C16 | −0.1018 (4) | 1.17840 (16) | −0.07974 (12) | 0.0803 (7) | |
H16 | −0.2379 | 1.2071 | −0.0742 | 0.096* | |
C5 | 0.0343 (4) | 0.69815 (16) | 0.05699 (9) | 0.0795 (7) | |
H5 | −0.0973 | 0.6984 | 0.0355 | 0.095* | |
C1 | 0.2831 (4) | 0.77194 (15) | 0.12906 (11) | 0.0720 (6) | |
C6 | 0.0818 (4) | 0.77415 (14) | 0.09806 (9) | 0.0635 (6) | |
C19 | 0.3026 (4) | 1.09673 (16) | −0.09734 (12) | 0.0848 (7) | |
H19 | 0.4397 | 1.0695 | −0.1038 | 0.102* | |
C17 | −0.0095 (5) | 1.17723 (17) | −0.13826 (12) | 0.0919 (8) | |
H17 | −0.0835 | 1.2042 | −0.1718 | 0.110* | |
C3 | 0.3740 (6) | 0.62313 (19) | 0.07855 (15) | 0.1027 (9) | |
H3 | 0.4721 | 0.5726 | 0.0719 | 0.123* | |
C2 | 0.4287 (4) | 0.69612 (18) | 0.11904 (13) | 0.0940 (8) | |
H2A | 0.5621 | 0.6949 | 0.1396 | 0.113* | |
C18 | 0.1903 (5) | 1.13633 (16) | −0.14639 (13) | 0.0882 (7) | |
H18 | 0.2521 | 1.1351 | −0.1858 | 0.106* | |
C9 | −0.2941 (4) | 0.99545 (17) | 0.22072 (10) | 0.0861 (7) | |
H9A | −0.4196 | 1.0382 | 0.2234 | 0.103* | |
H9B | −0.3427 | 0.9302 | 0.2306 | 0.103* | |
C4 | 0.1800 (6) | 0.62283 (17) | 0.04797 (13) | 0.0955 (9) | |
H4 | 0.1454 | 0.5722 | 0.0211 | 0.115* | |
C12 | 0.0551 (5) | 1.13028 (19) | 0.18700 (12) | 0.1004 (8) | |
H12A | 0.1016 | 1.1960 | 0.1774 | 0.120* | |
H12B | 0.1822 | 1.0884 | 0.1850 | 0.120* | |
C10 | −0.1265 (5) | 1.0268 (2) | 0.26770 (11) | 0.1056 (9) | |
H10A | −0.0067 | 0.9807 | 0.2680 | 0.127* | |
H10B | −0.1918 | 1.0272 | 0.3087 | 0.127* | |
C11 | −0.0396 (6) | 1.1276 (2) | 0.25261 (13) | 0.1206 (10) | |
H11A | 0.0729 | 1.1451 | 0.2823 | 0.145* | |
H11B | −0.1568 | 1.1747 | 0.2560 | 0.145* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N2 | 0.0736 (12) | 0.0638 (10) | 0.0823 (12) | 0.0124 (10) | 0.0150 (11) | 0.0022 (10) |
N1 | 0.0665 (11) | 0.0612 (10) | 0.0686 (10) | 0.0021 (9) | −0.0040 (9) | −0.0028 (9) |
C14 | 0.0631 (14) | 0.0491 (11) | 0.0953 (16) | 0.0074 (10) | 0.0081 (14) | −0.0095 (11) |
O1 | 0.0795 (11) | 0.0822 (10) | 0.1249 (12) | 0.0047 (10) | −0.0239 (11) | −0.0169 (10) |
C15 | 0.0558 (12) | 0.0503 (11) | 0.0807 (14) | −0.0014 (10) | 0.0059 (12) | −0.0102 (10) |
C7 | 0.0657 (14) | 0.0729 (13) | 0.0540 (11) | −0.0063 (12) | 0.0026 (11) | 0.0031 (11) |
C13 | 0.0736 (15) | 0.0627 (12) | 0.0846 (15) | 0.0136 (11) | 0.0117 (14) | −0.0044 (12) |
C20 | 0.0635 (14) | 0.0615 (12) | 0.0848 (16) | 0.0066 (11) | 0.0056 (14) | −0.0014 (12) |
O2 | 0.0858 (12) | 0.1315 (14) | 0.1009 (12) | 0.0447 (11) | 0.0156 (11) | 0.0126 (12) |
C8 | 0.0585 (13) | 0.0764 (13) | 0.0662 (13) | 0.0082 (12) | −0.0002 (11) | −0.0029 (11) |
C16 | 0.0686 (15) | 0.0780 (14) | 0.0943 (17) | 0.0114 (12) | −0.0031 (15) | −0.0093 (14) |
C5 | 0.1023 (19) | 0.0715 (14) | 0.0649 (13) | −0.0134 (15) | 0.0107 (14) | −0.0049 (11) |
C1 | 0.0746 (16) | 0.0562 (12) | 0.0850 (16) | −0.0052 (12) | 0.0086 (14) | 0.0037 (12) |
C6 | 0.0739 (16) | 0.0567 (12) | 0.0600 (12) | −0.0067 (12) | 0.0075 (12) | 0.0038 (10) |
C19 | 0.0761 (16) | 0.0802 (15) | 0.0980 (18) | 0.0085 (14) | 0.0251 (16) | −0.0053 (14) |
C17 | 0.104 (2) | 0.0924 (17) | 0.0795 (17) | 0.0148 (16) | −0.0074 (17) | −0.0083 (14) |
C3 | 0.116 (3) | 0.0641 (16) | 0.128 (2) | 0.0091 (17) | 0.046 (2) | 0.0023 (16) |
C2 | 0.0843 (18) | 0.0730 (15) | 0.125 (2) | 0.0094 (15) | 0.0115 (17) | 0.0144 (16) |
C18 | 0.104 (2) | 0.0741 (15) | 0.0870 (18) | 0.0034 (16) | 0.0185 (17) | −0.0029 (13) |
C9 | 0.0863 (17) | 0.0986 (16) | 0.0734 (15) | 0.0124 (15) | 0.0108 (14) | 0.0039 (13) |
C4 | 0.133 (3) | 0.0620 (15) | 0.0916 (19) | −0.0111 (18) | 0.037 (2) | −0.0087 (13) |
C12 | 0.101 (2) | 0.0944 (18) | 0.1055 (19) | −0.0143 (16) | 0.0050 (17) | −0.0323 (14) |
C10 | 0.115 (2) | 0.133 (2) | 0.0689 (15) | 0.028 (2) | −0.0044 (17) | −0.0073 (16) |
C11 | 0.122 (2) | 0.145 (3) | 0.0947 (19) | −0.005 (2) | −0.0084 (19) | −0.0495 (19) |
N2—C14 | 1.273 (3) | C5—H5 | 0.9300 |
N2—C13 | 1.467 (3) | C1—C2 | 1.390 (3) |
N1—C7 | 1.285 (2) | C1—C6 | 1.402 (3) |
N1—C8 | 1.467 (2) | C19—C18 | 1.373 (3) |
C14—C15 | 1.453 (3) | C19—H19 | 0.9300 |
C14—H14 | 0.9300 | C17—C18 | 1.359 (4) |
O1—C1 | 1.366 (2) | C17—H17 | 0.9300 |
O1—H1 | 0.8200 | C3—C4 | 1.358 (4) |
C15—C16 | 1.389 (3) | C3—C2 | 1.372 (4) |
C15—C20 | 1.411 (3) | C3—H3 | 0.9300 |
C7—C6 | 1.448 (3) | C2—H2A | 0.9300 |
C7—H7 | 0.9300 | C18—H18 | 0.9300 |
C13—C12 | 1.504 (3) | C9—C10 | 1.504 (4) |
C13—C8 | 1.538 (3) | C9—H9A | 0.9700 |
C13—H13 | 0.9800 | C9—H9B | 0.9700 |
C20—O2 | 1.355 (2) | C4—H4 | 0.9300 |
C20—C19 | 1.378 (3) | C12—C11 | 1.528 (4) |
O2—H2 | 0.8200 | C12—H12A | 0.9700 |
C8—C9 | 1.523 (3) | C12—H12B | 0.9700 |
C8—H8 | 0.9800 | C10—C11 | 1.522 (4) |
C16—C17 | 1.382 (3) | C10—H10A | 0.9700 |
C16—H16 | 0.9300 | C10—H10B | 0.9700 |
C5—C4 | 1.381 (4) | C11—H11A | 0.9700 |
C5—C6 | 1.400 (3) | C11—H11B | 0.9700 |
C14—N2—C13 | 120.62 (18) | C18—C19—H19 | 119.8 |
C7—N1—C8 | 119.17 (18) | C20—C19—H19 | 119.8 |
N2—C14—C15 | 121.72 (19) | C18—C17—C16 | 119.4 (3) |
N2—C14—H14 | 119.1 | C18—C17—H17 | 120.3 |
C15—C14—H14 | 119.1 | C16—C17—H17 | 120.3 |
C1—O1—H1 | 109.5 | C4—C3—C2 | 121.6 (3) |
C16—C15—C20 | 118.0 (2) | C4—C3—H3 | 119.2 |
C16—C15—C14 | 121.0 (2) | C2—C3—H3 | 119.2 |
C20—C15—C14 | 121.0 (2) | C3—C2—C1 | 119.5 (3) |
N1—C7—C6 | 123.0 (2) | C3—C2—H2A | 120.3 |
N1—C7—H7 | 118.5 | C1—C2—H2A | 120.3 |
C6—C7—H7 | 118.5 | C17—C18—C19 | 121.1 (2) |
N2—C13—C12 | 108.59 (19) | C17—C18—H18 | 119.5 |
N2—C13—C8 | 110.31 (16) | C19—C18—H18 | 119.5 |
C12—C13—C8 | 112.61 (19) | C10—C9—C8 | 112.5 (2) |
N2—C13—H13 | 108.4 | C10—C9—H9A | 109.1 |
C12—C13—H13 | 108.4 | C8—C9—H9A | 109.1 |
C8—C13—H13 | 108.4 | C10—C9—H9B | 109.1 |
O2—C20—C19 | 119.4 (2) | C8—C9—H9B | 109.1 |
O2—C20—C15 | 120.8 (2) | H9A—C9—H9B | 107.8 |
C19—C20—C15 | 119.7 (2) | C3—C4—C5 | 119.6 (3) |
C20—O2—H2 | 109.5 | C3—C4—H4 | 120.2 |
N1—C8—C9 | 110.34 (17) | C5—C4—H4 | 120.2 |
N1—C8—C13 | 109.95 (16) | C13—C12—C11 | 111.4 (2) |
C9—C8—C13 | 110.13 (17) | C13—C12—H12A | 109.3 |
N1—C8—H8 | 108.8 | C11—C12—H12A | 109.3 |
C9—C8—H8 | 108.8 | C13—C12—H12B | 109.3 |
C13—C8—H8 | 108.8 | C11—C12—H12B | 109.3 |
C17—C16—C15 | 121.4 (2) | H12A—C12—H12B | 108.0 |
C17—C16—H16 | 119.3 | C9—C10—C11 | 110.9 (2) |
C15—C16—H16 | 119.3 | C9—C10—H10A | 109.5 |
C4—C5—C6 | 121.0 (3) | C11—C10—H10A | 109.5 |
C4—C5—H5 | 119.5 | C9—C10—H10B | 109.5 |
C6—C5—H5 | 119.5 | C11—C10—H10B | 109.5 |
O1—C1—C2 | 118.7 (2) | H10A—C10—H10B | 108.1 |
O1—C1—C6 | 120.8 (2) | C10—C11—C12 | 110.6 (2) |
C2—C1—C6 | 120.4 (2) | C10—C11—H11A | 109.5 |
C5—C6—C1 | 117.9 (2) | C12—C11—H11A | 109.5 |
C5—C6—C7 | 120.9 (2) | C10—C11—H11B | 109.5 |
C1—C6—C7 | 121.2 (2) | C12—C11—H11B | 109.5 |
C18—C19—C20 | 120.4 (2) | H11A—C11—H11B | 108.1 |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.82 | 1.87 | 2.599 (3) | 148 |
O2—H2···N2 | 0.82 | 1.84 | 2.577 (3) | 148 |
Experimental details
Crystal data | |
Chemical formula | C20H22N2O2 |
Mr | 322.40 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 296 |
a, b, c (Å) | 6.125 (3), 13.763 (6), 21.537 (9) |
V (Å3) | 1815.4 (13) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.25 × 0.15 × 0.12 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2001) |
Tmin, Tmax | 0.987, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9439, 4195, 2178 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.664 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.115, 0.99 |
No. of reflections | 4195 |
No. of parameters | 219 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.09, −0.10 |
Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and WinGX (Farrugia, 1999).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.82 | 1.87 | 2.599 (3) | 148 |
O2—H2···N2 | 0.82 | 1.84 | 2.577 (3) | 148 |
Acknowledgements
This work was supported by the National Natural Science Foundation of China (Nos. 20971062 and 21171081).
References
Bruker (2001). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cannadine, J. C., Corden, J. P., Errington, W., Moore, P. & Wallbridge, M. G. H. (1996). Acta Cryst. C52, 1014–1017. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Khalaji, A. D., Hadadzadeh, H., Fejfarova, K. & Dusek, M. (2010). Polyhedron, 29, 807–812. Web of Science CSD CrossRef CAS Google Scholar
Liu, Q., Ding, M., Lin, Y. & Xing, Y. (1997). Acta Cryst. C53, 1671–1673. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Man, W.-L., Kwong, H.-K., Lam, W. W. Y., Xiang, J., Wong, T.-W., Lam, W.-H., Wong, W.-T., Peng, S.-M. & Lau, T.-C. (2008). Inorg. Chem. 47, 5936–5944. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Xu, Z., Zhou, M.-D., Drees, M., Chaffey-Millar, H., Herdtweck, E., Herrmann, W. A. & Kuhn, F. E. (2009). Inorg. Chem. 48, 6812–6822. Web of Science CSD CrossRef PubMed CAS 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.
1,2-Cyclohexanediamine has trans-cis isomers, so their reaction products are also isomers. trans-N,N'-Bis(salicylidene)-1,2-cyclohexanediamine has been prepared and characterized via X-ray crystallography (Cannadine et al., 1996; Liu et al., 1997). The compound is current of interest due to its fascinating versatility as coordination ligand (Khalaji et al., 2010; Man et al., 2008; Xu et al., 2009). As cis-isomer is difficult to form complex, it has received relatively few studies.
The stucture of the title compound is shown in Fig. 1. The two N-salicylidene groups are cis in the structure with the same constitution but differ in the arrangement of their atoms in space. Dihedral angel between aromatic rings is 60.5 (1) °, between the ring of C1—C6 and C8/C10/C12 is 88.8 (1) °, between the ring of C15—C20 and C8/C10/C12 is 75.2 (1)°, respectively. hydroxy groups and imine groups are involved in intramolecular hydrogen bonding (Table 1).