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Acta Cryst. (2008). E64, o1917    [ doi:10.1107/S1600536808028468 ]

6,6'-Dihydroxy-2,2'-[(butane-1,4-diyldioxy)bis(nitrilomethylidyne)]diphenol

W.-K. Dong, X.-N. He, Y.-X. Sun, L. Xu and Y.-H. Guan

Abstract top

The molecule of the centrosymmetric title compound, C18H20N2O6, assumes an E configuration with respect to the azomethine C=N bond. The imino group is coplanar with the aromatic ring. Intramolecular O-H...O and O-H...N bonds are found between the hydroxyl groups and adjacent O (or N) atoms. In the crystal structure, intermolecular O-H...O bonds link each molecule to two others, forming a layered network.

Comment top

The design of supramolecular structures involves molecules for which intermolecular hydrogen bonds act as driving, directional and cohesive forces (Sharma, 2002). Although many stable and well documented structures have been reported (Fan et al., 2006; Wang et al., 2003), the supramolecular structures of salen-type bisoxime compounds have rarely been determined. The first reported supramolecular salen-type bisoxime compound, 6,6'-dihydroxy-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol has an intermolecular hydrogen bond network involving four hydroxyl groups and cocrystallized water molecules (Akine et al., 2006). In this article, we report the synthesis and structure of the title compound (I) (Fig. 1).

(I) lies across a crystallographic inversion centre to give 1/2 molecule per asymmetric unit. It assumes an E configuration with respect to the azomethine C═N bond. The imino group is coplanar with the aromatic ring. The planar units are parallel to one another but extend in opposite directions from the tetramethylene bridge. Strong intramolecular O(3)—H(3)···O(2) and O(2)—H(2)···N(1) bonds are found between the hydroxyl groups and adjacent O (or N) atoms (Table 1). This is similar to what was observed in our previously reported salen-type bisoxime compounds (Wang et al., 2007; Dong et al., 2007; Dong et al., 2008a).

In the crystal packing weak intermolecular O—H···O hydrogen bonds link each molecule to 4 others, forming an infinite three-dimensional supramolecular structure (Figs. 2 and 3) that differs from the structures of 6,6'-dihydroxy-2,2'-[ethylenedioxybis(nitrilomethylidyne)]diphenol (Akine et al., 2006) and 6,6'-dihydroxy-2,2'-[(pentane-1,5-diyldioxy)bis(nitrilomethylidyne)]diphenol (Dong et al., 2008b), in which the molecules exhibit one-dimensional chains formed through strong intermolecular π–π stacking interactions or weak intermolecular hydrogen bonds.

Related literature top

For background information, see: Sharma (2002). For related structures, see: Fan et al. (2006); Wang et al. (2003); Akine et al. (2006). Dong et al. (2007, 2008a,b); Wang et al. (2007).

Experimental top

The title compound was synthesized according to an analogous method reported earlier (Dong et al., 2007). To an ethanol solution (5 ml) of 2,3-dihydroxybenzaldehyde (276.6 mg, 2.0 mmol) was added an ethanol solution (5 ml) of 1,4-bis(aminooxy)butane (120.0 mg, 1.0 mmol). After the solution had been stirred at 328 K for 3 h, the reaction mixture was separated by filtration, washed successively with ethanol and ethanol/hexane (1:4), respectively. The product was dried under reduced pressure and purified with recrystallization from ethanol to yield 59.9 mg of pale-brown crystalline solid. Yield, 17.2%, m.p. 388–389 K. Anal. Calc. (%) for C18H20N2O6: C, 59.99; H, 5.59; N, 7.77. Found: C, 60.23; H, 5.45; N, 7.60.

Block-shaped crystals of (I) suitable for X-ray crystal analysis were grown from a mixture of tetrahydrofuran/ethanol (1:1) solution by slow evaporation at room temperature, which afforded pale-brown crystals.

Refinement top

Non-H atoms were refined anisotropically. H atoms were treated as riding atoms with distances C—H = 0.97 (CH2), 0.93 Å (CH), O—H = 0.82 Å and Uiso(H) = 1.2 Ueq(C) and 1.5 Ueq(O).

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SMART (Siemens, 1996); data reduction: SAINT (Siemens, 1996); 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: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with atom numbering scheme [Symmetry codes: -x,-y + 2,-z + 1]. Displacement ellipsoids for non-hydrogen atoms are drawn at the 30% probability level.
[Figure 2] Fig. 2. Three-dimensional packing diagram of the title compound along c axis showing the E configuration.
[Figure 3] Fig. 3. Part of the supramolecular structure of the title compound along b axis. Intra- and intermolecular hydrogen bonds are shown as dashed lines.
6,6'-Dihydroxy-2,2'-[(butane-1,4-diyldioxy)bis(nitrilomethylidyne)]diphenol top
Crystal data top
C18H20N2O6Z = 4
Mr = 360.36F(000) = 760
Mmonoclinic, C2/cDx = 1.362 Mg m−3
Hall symbol: -C 2ycMo Kα radiation, λ = 0.71073 Å
a = 27.484 (3) ÅCell parameters from 1695 reflections
b = 4.7106 (7) Åθ = 2.4–27.8°
c = 14.0081 (19) ŵ = 0.10 mm−1
α = 90°T = 298 K
β = 104.306 (2)°Block-shaped, pale-brown
γ = 90°0.55 × 0.53 × 0.48 mm
V = 1757.4 (4) Å3
Data collection top
Bruker Smart 1000 CCD area-detector
diffractometer		1555 independent reflections
Radiation source: fine-focus sealed tube1112 reflections with I > 2σ(I)
graphiteRint = 0.026
φ and ω scansθmax = 25.0°, θmin = 1.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −17→32
Tmin = 0.945, Tmax = 0.952k = −5→5
4086 measured reflectionsl = −16→16
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H-atom parameters constrained
S = 1.10 w = 1/[σ2(Fo2) + (0.0457P)2 + 0.5441P]
where P = (Fo2 + 2Fc2)/3
1555 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 0.16 e Å−3
0 restraintsΔρmin = −0.16 e Å−3
Crystal data top
C18H20N2O6γ = 90°
Mr = 360.36V = 1757.4 (4) Å3
Mmonoclinic, C2/cZ = 4
a = 27.484 (3) ÅMo Kα radiation
b = 4.7106 (7) ŵ = 0.10 mm−1
c = 14.0081 (19) ÅT = 298 K
α = 90°0.55 × 0.53 × 0.48 mm
β = 104.306 (2)°
Data collection top
Bruker Smart 1000 CCD area-detector
diffractometer		1555 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		1112 reflections with I > 2σ(I)
Tmin = 0.945, Tmax = 0.952Rint = 0.026
4086 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.106Δρmax = 0.16 e Å−3
S = 1.10Δρmin = −0.16 e Å−3
1555 reflectionsAbsolute structure: ?
118 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.08963 (5)0.5854 (3)0.37586 (9)0.0445 (4)
O10.07135 (4)0.7516 (3)0.44261 (7)0.0505 (3)
O20.09612 (4)0.3675 (3)0.20520 (8)0.0595 (4)
H20.08480.47410.24070.089*
O30.14491 (5)0.0061 (3)0.11078 (8)0.0719 (5)
H30.12130.11370.08900.108*
C10.02835 (6)0.9102 (4)0.39001 (12)0.0484 (4)
H1A0.00200.78190.35650.058*
H1B0.03751.03120.34110.058*
C20.01029 (6)1.0875 (4)0.46377 (12)0.0486 (5)
H2A−0.01581.21500.42870.058*
H2B0.03791.20270.50020.058*
C30.12781 (6)0.4381 (4)0.41858 (12)0.0444 (4)
H3A0.14010.45260.48650.053*
C40.15231 (5)0.2489 (3)0.36349 (11)0.0396 (4)
C50.13584 (6)0.2207 (4)0.26086 (11)0.0420 (4)
C60.16024 (6)0.0352 (4)0.21112 (12)0.0474 (4)
C70.20050 (7)−0.1205 (4)0.26152 (13)0.0531 (5)
H70.2165−0.24510.22770.064*
C80.21755 (6)−0.0930 (4)0.36307 (13)0.0534 (5)
H80.2451−0.19770.39710.064*
C90.19369 (6)0.0890 (4)0.41324 (12)0.0475 (4)
H90.20520.10620.48120.057*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0463 (8)0.0494 (9)0.0400 (7)−0.0006 (7)0.0146 (6)−0.0072 (7)
O10.0512 (7)0.0609 (8)0.0389 (6)0.0100 (6)0.0105 (5)−0.0093 (6)
O20.0598 (8)0.0715 (9)0.0411 (6)0.0174 (6)0.0011 (6)−0.0067 (6)
O30.0830 (9)0.0906 (11)0.0404 (7)0.0200 (8)0.0123 (6)−0.0101 (7)
C10.0467 (9)0.0537 (11)0.0438 (9)0.0022 (8)0.0094 (7)0.0009 (8)
C20.0488 (10)0.0465 (11)0.0524 (10)0.0047 (8)0.0158 (8)0.0026 (8)
C30.0451 (9)0.0513 (11)0.0359 (8)−0.0040 (8)0.0088 (7)−0.0031 (8)
C40.0384 (8)0.0428 (10)0.0379 (8)−0.0055 (7)0.0102 (7)−0.0011 (7)
C50.0396 (9)0.0452 (10)0.0400 (9)−0.0013 (7)0.0077 (7)0.0014 (8)
C60.0525 (10)0.0513 (11)0.0405 (9)−0.0021 (9)0.0153 (8)−0.0034 (8)
C70.0529 (10)0.0528 (11)0.0586 (11)0.0045 (9)0.0232 (9)−0.0016 (9)
C80.0454 (10)0.0570 (12)0.0578 (11)0.0078 (9)0.0124 (8)0.0099 (9)
C90.0448 (9)0.0565 (11)0.0402 (9)−0.0010 (8)0.0083 (7)0.0053 (8)
Geometric parameters (Å, °) top
N1—C31.277 (2)C2—H2B0.9700
N1—O11.4041 (16)C3—C41.449 (2)
O1—C11.4377 (19)C3—H3A0.9300
O2—C51.3627 (19)C4—C91.398 (2)
O2—H20.8200C4—C51.403 (2)
O3—C61.3709 (19)C5—C61.389 (2)
O3—H30.8200C6—C71.369 (2)
C1—C21.505 (2)C7—C81.389 (2)
C1—H1A0.9700C7—H70.9300
C1—H1B0.9700C8—C91.373 (2)
C2—C2i1.521 (3)C8—H80.9300
C2—H2A0.9700C9—H90.9300
C3—N1—O1112.25 (12)C9—C4—C5118.48 (15)
N1—O1—C1109.42 (11)C9—C4—C3119.58 (14)
C5—O2—H2109.5C5—C4—C3121.94 (14)
C6—O3—H3109.5O2—C5—C6116.75 (14)
O1—C1—C2107.79 (13)O2—C5—C4123.26 (15)
O1—C1—H1A110.1C6—C5—C4119.99 (15)
C2—C1—H1A110.1C7—C6—O3118.65 (16)
O1—C1—H1B110.1C7—C6—C5120.48 (15)
C2—C1—H1B110.1O3—C6—C5120.87 (15)
H1A—C1—H1B108.5C6—C7—C8120.18 (17)
C1—C2—C2i113.41 (18)C6—C7—H7119.9
C1—C2—H2A108.9C8—C7—H7119.9
C2i—C2—H2A108.9C9—C8—C7119.96 (16)
C1—C2—H2B108.9C9—C8—H8120.0
C2i—C2—H2B108.9C7—C8—H8120.0
H2A—C2—H2B107.7C8—C9—C4120.90 (16)
N1—C3—C4121.39 (14)C8—C9—H9119.6
N1—C3—H3A119.3C4—C9—H9119.6
C4—C3—H3A119.3
C3—N1—O1—C1−179.64 (14)O2—C5—C6—C7−179.99 (15)
N1—O1—C1—C2−179.36 (12)C4—C5—C6—C7−0.2 (3)
O1—C1—C2—C2i−66.3 (2)O2—C5—C6—O30.7 (2)
O1—N1—C3—C4179.32 (13)C4—C5—C6—O3−179.56 (16)
N1—C3—C4—C9−179.32 (15)O3—C6—C7—C8178.97 (17)
N1—C3—C4—C50.8 (2)C5—C6—C7—C8−0.4 (3)
C9—C4—C5—O2−179.62 (14)C6—C7—C8—C90.6 (3)
C3—C4—C5—O20.2 (3)C7—C8—C9—C4−0.2 (3)
C9—C4—C5—C60.6 (2)C5—C4—C9—C8−0.4 (2)
C3—C4—C5—C6−179.53 (15)C3—C4—C9—C8179.71 (15)
Symmetry codes: (i) −x, −y+2, −z+1.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.821.942.648 (2)145.
O3—H3···O20.822.262.706 (2)115.
O3—H3···O1ii0.822.262.930 (2)139.
Symmetry codes: (ii) x, −y+1, z−1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.821.942.648 (2)145.
O3—H3···O20.822.262.706 (2)115.
O3—H3···O1i0.822.262.930 (2)139.
Symmetry codes: (i) x, −y+1, z−1/2.
Acknowledgements top

This work was supported by the Foundation of the Education Department of Gansu Province (No. 0604-01) and the `Qing Lan' Talent Engineering Fund of Lanzhou Jiaotong University (No. QL-03-01 A), which are gratefully acknowledged.

references
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