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Acta Cryst. (2008). E64, o2059    [ doi:10.1107/S160053680803136X ]

2,2'-{1,1'-[Pentane-1,5-diylbis(oxynitrilo)]diethylidyne}diphenol

W.-K. Dong, Z.-W. Lv, X.-N. He, Y.-H. Guan and J.-F. Tong

Abstract top

In the title compound, C21H26N2O4, there is half a molecule in the asymmetric unit with a crystallographic twofold rotation axis passing through the central C atom of the -CH=N-O-(CH2)5-O-N=CH- bridge. The dihedral angle formed by the two benzene rings is 80.85 (2)°. Strong intramolecular O-H...N and C-H...O hydrogen bonds help to establish the molecular conformation. There are also weak intermolecular [pi]-[pi] stacking interactions between neighbouring benzene rings [centroid-centroid separation = 3.502 (3) Å].

Comment top

salen-type compounds containing strong donor sites such as oxygen and imine nitrogen atoms and their metal complexes have been the subject of extensive investigation (Bhadbhade & Srinivas, 1993). Structures of salen-type compounds derived from O-alkyl oxime moiety (–CH═N—O-(CH2)n-O—N═CH–) instead of the imine moiety and closely related to the title compound (Wang et al., 2007; Dong et al., 2008; Dong et al., 2007), are known. In this research, we report the synthesis and crystal structure of the title compound, and shown in Fig. 1.

The single-crystal structure of the title compound is built up by discrete C21H26N2O4 molecules, within all bond lengths are in normal ranges. There is 1/2 molecule per asymmetric unit with a crystallographic twofold rotation axis passing through the central carbon (symmetry code: -x, y, -z) of the five carbon atoms in the (—CH═N—O—(CH2)5—O—N═CH—) bridge. The dihedral angle formed by the two benzene rings in the molecule of the title compound is 80.85 (2)°. The strong intramolecular O2—H2···N1 and C4—H4A···O1 hydrogen bonds play an important role in the stability of the crystal structure in the title compound. The five carbon atoms in the C1—C2—C3—C2A—C1A bridge are almost in the same plane with slight deviation of 0.015 and 0.029 Å below for C1, C2A, 0.015 and 0.029 Å above the plane for C2 and C1A (symmetry code A: -x, y, -z + 1), respectively. In the crystal structure, there is weak intermolecular π–π stacking interaction between the neighbouring benzene rings, and the inter-molecular plane-to-plane distance is 3.502 (3) Å along b axis. This structure is not similar to what was observed in our previously reported series of salen-type compound containing two- (Wang et al., 2007), three- (Dong et al., 2008) and four-methene (Dong et al., 2007) bridge.

Related literature top

For related literature, see: Bhadbhade & Srinivas (1993); Dong et al. (2007, 2008); Wang et al. (2007); Xu et al. (2007). [From the Section Editors: It would be much more useful to readers if the "Related literature" section had some kind of simple sub-division, so that, instead of just "For related literature, see···" it said, for example, "For general background, see···. For related structures, see···." etc. Please revise this section as indicated.]

Experimental top

2,2'-[1,1'-(Pentane-1,5-diyldioxydinitrilo)diethylidyne]diphenol was synthesized according to an analogous method reported earlier (Wang et al., 2007; Xu et al., 2007). To an ethanol solution (5 ml) of 2'-hydroxyacetophenone (516.2 mg, 4.00 mmol) was added an ethanol solution (3 ml) of 1,5-bis(aminooxy)pentane (268.4 mg, 2.00 mmol). The reaction mixture was stirred at 328 K for 4 h. The formed precipitate was separated by filtration, and washed successively with ethanol and ethanol–hexane (1:4), respectively. The product was dried under vacuum to yield 410.9 mg of the title compound. Yield, 55.5%. mp. 344–345 K. Anal. Calc. for C17H16Cl2N2O2: C, 68.09; H, 7.07; N, 7.56. Found: C, 68.19; H, 7.21; N, 7.42.

Colorless block-like single crystals suitable for X-ray diffraction studies were obtained after two weeks by slow evaporation from a diethyl-ether solution of the title compound.

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: SAINT (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: A: -x, y, -z + 1]. Displacement ellipsoids for non-hydrogen atoms are drawn at the 30% probability level.
2,2'-{1,1'-[Pentane-1,5-diylbis(oxynitrilo)]diethylidyne}diphenol top
Crystal data top
C21H26N2O4F(000) = 396
Mr = 370.44Dx = 1.260 Mg m−3
Monoclinic, C2Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2yCell parameters from 813 reflections
a = 12.9691 (13) Åθ = 2.5–23.2°
b = 4.601 (1) ŵ = 0.09 mm−1
c = 16.3639 (16) ÅT = 298 K
β = 91.621 (1)°Needle-like, colourless
V = 976.1 (3) Å30.48 × 0.40 × 0.32 mm
Z = 2
Data collection top
Siemens SMART 1000 CCD area-detector
diffractometer		972 independent reflections
Radiation source: fine-focus sealed tube646 reflections with I > 2σ(I)
graphiteRint = 0.038
φ and ω scansθmax = 25.0°, θmin = 2.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −15→15
Tmin = 0.959, Tmax = 0.973k = −5→5
2421 measured reflectionsl = −19→10
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0568P)2 + 0.2844P]
where P = (Fo2 + 2Fc2)/3
972 reflections(Δ/σ)max < 0.001
123 parametersΔρmax = 0.15 e Å−3
2 restraintsΔρmin = −0.12 e Å−3
Crystal data top
C21H26N2O4V = 976.1 (3) Å3
Mr = 370.44Z = 2
Monoclinic, C2Mo Kα radiation
a = 12.9691 (13) ŵ = 0.09 mm−1
b = 4.601 (1) ÅT = 298 K
c = 16.3639 (16) Å0.48 × 0.40 × 0.32 mm
β = 91.621 (1)°
Data collection top
Siemens SMART 1000 CCD area-detector
diffractometer		972 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		646 reflections with I > 2σ(I)
Tmin = 0.959, Tmax = 0.973Rint = 0.038
2421 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.123Δρmax = 0.15 e Å−3
S = 1.04Δρmin = −0.12 e Å−3
972 reflectionsAbsolute structure: ?
123 parametersFlack parameter: ?
2 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*/UeqOcc. (<1)
N10.1857 (2)0.7552 (7)0.30501 (17)0.0533 (8)
O10.23002 (19)0.6005 (8)0.37063 (14)0.0656 (7)
O20.0337 (2)0.9262 (9)0.21462 (17)0.0796 (9)
H20.06290.82230.24880.119*
C10.1512 (3)0.4342 (11)0.4082 (2)0.0607 (10)
H1A0.18340.29270.44470.073*
H1B0.11260.32860.36620.073*
C20.0778 (3)0.6170 (10)0.4558 (2)0.0551 (9)
H2A0.11690.73330.49520.066*
H2B0.04180.74890.41860.066*
C30.00000.4391 (13)0.50000.0526 (12)
H3A0.03610.31470.53920.063*0.50
H3B−0.03610.31470.46080.063*0.50
C40.3610 (3)0.9300 (15)0.2926 (2)0.0836 (14)
H4A0.37360.80410.33860.125*
H4B0.37871.12590.30740.125*
H4C0.40230.86880.24790.125*
C50.2494 (3)0.9162 (9)0.2673 (2)0.0494 (9)
C60.2084 (3)1.0860 (9)0.1985 (2)0.0485 (9)
C70.1043 (3)1.0870 (11)0.1759 (2)0.0573 (9)
C80.0682 (3)1.2544 (12)0.1116 (2)0.0745 (12)
H8−0.00171.25350.09710.089*
C90.1348 (4)1.4212 (13)0.0693 (2)0.0773 (13)
H90.10991.53430.02600.093*
C100.2363 (4)1.4250 (12)0.0892 (2)0.0735 (12)
H100.28121.53890.05950.088*
C110.2732 (3)1.2605 (10)0.1533 (2)0.0610 (11)
H110.34331.26560.16700.073*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0547 (18)0.0514 (18)0.0545 (16)0.0036 (18)0.0125 (14)−0.0018 (17)
O10.0574 (15)0.0702 (16)0.0701 (15)0.0067 (17)0.0167 (12)0.0136 (17)
O20.0532 (16)0.0868 (19)0.099 (2)−0.006 (2)0.0049 (14)0.018 (2)
C10.065 (2)0.053 (2)0.066 (2)0.011 (3)0.0173 (19)0.009 (2)
C20.062 (2)0.045 (2)0.059 (2)−0.001 (2)0.0143 (17)−0.002 (2)
C30.062 (3)0.041 (3)0.054 (3)0.0000.009 (2)0.000
C40.055 (2)0.107 (4)0.089 (3)−0.014 (3)0.004 (2)0.015 (4)
C50.0469 (19)0.048 (2)0.0541 (19)−0.003 (2)0.0155 (17)−0.010 (2)
C60.053 (2)0.0447 (19)0.0478 (18)−0.011 (2)0.0105 (16)−0.010 (2)
C70.056 (2)0.055 (2)0.062 (2)−0.004 (3)0.0132 (18)−0.005 (3)
C80.071 (3)0.078 (3)0.074 (3)−0.001 (3)−0.004 (2)0.005 (3)
C90.106 (4)0.067 (3)0.058 (2)0.001 (3)0.000 (2)0.001 (3)
C100.098 (4)0.066 (3)0.058 (2)−0.023 (3)0.014 (2)−0.004 (3)
C110.063 (2)0.062 (3)0.059 (2)−0.014 (3)0.013 (2)−0.012 (3)
Geometric parameters (Å, °) top
N1—C51.282 (4)C4—H4A0.9600
N1—O11.398 (4)C4—H4B0.9600
O1—C11.430 (5)C4—H4C0.9600
O2—C71.349 (5)C5—C61.459 (5)
O2—H20.8200C6—C71.389 (5)
C1—C21.504 (5)C6—C111.390 (5)
C1—H1A0.9700C7—C81.375 (5)
C1—H1B0.9700C8—C91.360 (6)
C2—C31.501 (5)C8—H80.9300
C2—H2A0.9700C9—C101.348 (6)
C2—H2B0.9700C9—H90.9300
C3—C2i1.501 (5)C10—C111.370 (6)
C3—H3A0.9700C10—H100.9300
C3—H3B0.9700C11—H110.9300
C4—C51.495 (5)
C5—N1—O1114.0 (3)C5—C4—H4C109.5
N1—O1—C1108.6 (3)H4A—C4—H4C109.5
C7—O2—H2109.5H4B—C4—H4C109.5
O1—C1—C2113.2 (4)N1—C5—C6117.0 (3)
O1—C1—H1A108.9N1—C5—C4121.6 (4)
C2—C1—H1A108.9C6—C5—C4121.3 (4)
O1—C1—H1B108.9C7—C6—C11117.0 (4)
C2—C1—H1B108.9C7—C6—C5122.5 (3)
H1A—C1—H1B107.7C11—C6—C5120.4 (3)
C3—C2—C1112.9 (3)O2—C7—C8116.4 (4)
C3—C2—H2A109.0O2—C7—C6122.7 (4)
C1—C2—H2A109.0C8—C7—C6120.8 (4)
C3—C2—H2B109.0C9—C8—C7119.9 (4)
C1—C2—H2B109.0C9—C8—H8120.1
H2A—C2—H2B107.8C7—C8—H8120.1
C2—C3—C2i113.9 (5)C10—C9—C8121.0 (5)
C2—C3—H3A108.8C10—C9—H9119.5
C2i—C3—H3A108.8C8—C9—H9119.5
C2—C3—H3B108.8C9—C10—C11119.7 (4)
C2i—C3—H3B108.8C9—C10—H10120.2
H3A—C3—H3B107.7C11—C10—H10120.2
C5—C4—H4A109.5C10—C11—C6121.6 (4)
C5—C4—H4B109.5C10—C11—H11119.2
H4A—C4—H4B109.5C6—C11—H11119.2
C5—N1—O1—C1179.0 (3)C5—C6—C7—O2−1.6 (6)
N1—O1—C1—C2−72.2 (4)C11—C6—C7—C80.0 (6)
O1—C1—C2—C3−175.9 (3)C5—C6—C7—C8178.7 (4)
C1—C2—C3—C2i−176.9 (4)O2—C7—C8—C9−179.6 (4)
O1—N1—C5—C6−179.5 (3)C6—C7—C8—C90.1 (6)
O1—N1—C5—C40.5 (5)C7—C8—C9—C100.2 (7)
N1—C5—C6—C72.9 (5)C8—C9—C10—C11−0.5 (8)
C4—C5—C6—C7−177.1 (4)C9—C10—C11—C60.6 (7)
N1—C5—C6—C11−178.5 (3)C7—C6—C11—C10−0.3 (6)
C4—C5—C6—C111.5 (6)C5—C6—C11—C10−179.1 (4)
C11—C6—C7—O2179.7 (4)
Symmetry codes: (i) −x, y, −z+1.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.821.842.553 (4)144
C4—H4A···O10.962.162.631 (5)109
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2···N10.821.842.553 (4)144
C4—H4A···O10.962.162.631 (5)109
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-03-01A), which are gratefully acknowledged.

references
References top

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