Bis(2-hydroxy-benzaldehyde oxime) O,O'-butane-1,4-diyldicarbonyl ether.

The mol-ecule of the title compound, C(20)H(20)N(2)O(6), lies across a crystallographic inversion centre, the asymmetric unit comprising one half-mol-ecule. An intra-molecular O-H⋯N hydrogen bond generates a six-membered ring, producing an S(6) ring motif. Pairs of inter-molecular C-H⋯O hydrogen bonds link neighbouring mol-ecules into a layer with R(2) (2)(38) ring motif. The crystal structure is further stabilized by the inter-molecular C-H⋯π inter-actions.

Related literature

For bond-length data, see Allen et al. (1987 ▶). For hydrogen bond motifs, see Bernstein et al. (1995 ▶). For Schiff bases, see: Granovski et al., (1993 ▶). For the synthesis, see: Hosseini Sarvari (2003 ▶).

Experimental

Crystal data

C20H20N2O6

M = 384.38

Monoclinic,

a = 13.0293 (11) Å

b = 5.5464 (4) Å

c = 25.538 (2) Å

β = 91.348 (7)°

V = 1845.0 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.10 mm−1

T = 120 K

0.45 × 0.11 × 0.10 mm

Data collection

STOE IPDSII diffractometer

Absorption correction: numerical (X-RED32; Stoe & Cie (2005 ▶) T min = 0.956, T max = 0.985

10357 measured reflections

2493 independent reflections

2098 reflections with I > 2σ(I)

R int = 0.046

Refinement

R[F 2 > 2σ(F 2)] = 0.047

wR(F 2) = 0.099

S = 1.10

2493 reflections

135 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.31 e Å−3

Δρmin = −0.20 e Å−3

Data collection: X-AREA (Stoe & Cie, 2005 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809016663/at2778sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809016663/at2778Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C20H20N2O6	F(000) = 808
Mr = 384.38	Dx = 1.384 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1302 reflections
a = 13.0293 (11) Å	θ = 3.1–29.2°
b = 5.5464 (4) Å	µ = 0.10 mm−1
c = 25.538 (2) Å	T = 120 K
β = 91.348 (7)°	Needle, colourless
V = 1845.0 (3) Å3	0.45 × 0.11 × 0.10 mm
Z = 4

STOE IPDS II diffractometer	2493 independent reflections
Radiation source: fine-focus sealed tube	2098 reflections with I > 2σ(I)
graphite	Rint = 0.091
Detector resolution: 0.15 pixels mm-1	θmax = 29.2°, θmin = 3.1°
rotation method scans	h = −17→17
Absorption correction: numerical (X-RED32; Stoe & Cie (2005)	k = −7→7
Tmin = 0.956, Tmax = 0.985	l = −35→34
41515 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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.099	H atoms treated by a mixture of independent and constrained refinement
S = 1.10	w = 1/[σ2(Fo2) + (0.0425P)2 + 1.8216P] where P = (Fo2 + 2Fc2)/3
2493 reflections	(Δ/σ)max = 0.004
135 parameters	Δρmax = 0.31 e Å−3
0 restraints	Δρmin = −0.20 e Å−3

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C1	0.79600 (9)	−0.3740 (2)	0.32698 (5)	0.0186 (3)
C2	0.73433 (10)	−0.5276 (2)	0.29667 (5)	0.0204 (3)
H2	0.7620	−0.6677	0.2828	0.025*
C3	0.63188 (10)	−0.4721 (2)	0.28720 (5)	0.0206 (3)
H3	0.5909	−0.5768	0.2674	0.025*
C4	0.58953 (9)	−0.2610 (3)	0.30699 (5)	0.0212 (3)
H4	0.5207	−0.2245	0.3004	0.025*
C5	0.65095 (9)	−0.1061 (2)	0.33650 (5)	0.0192 (3)
H5	0.6230	0.0355	0.3495	0.023*
C6	0.75482 (9)	−0.1590 (2)	0.34720 (5)	0.0168 (2)
C7	0.81678 (10)	0.0064 (2)	0.37953 (5)	0.0193 (3)
H7	0.7866 (13)	0.154 (3)	0.3912 (7)	0.027 (4)*
C8	1.05836 (10)	0.0434 (2)	0.43627 (5)	0.0204 (3)
C9	1.11260 (10)	0.2321 (2)	0.46898 (5)	0.0208 (3)
H9A	1.0741	0.2617	0.5004	0.025*
H9B	1.1155	0.3816	0.4494	0.025*
C10	1.22133 (10)	0.1530 (2)	0.48435 (5)	0.0206 (3)
H10B	1.2588	0.1167	0.4529	0.025*
H10A	1.2181	0.0069	0.5051	0.025*
N1	0.90918 (8)	−0.0542 (2)	0.39115 (4)	0.0224 (3)
O1	0.89508 (7)	−0.4424 (2)	0.33553 (4)	0.0289 (3)
H1	0.9268 (18)	−0.333 (5)	0.3572 (10)	0.062 (7)*
O2	0.96033 (7)	0.11970 (18)	0.42331 (4)	0.0223 (2)
O3	1.09270 (8)	−0.14750 (19)	0.42343 (4)	0.0271 (2)

	U11	U22	U33	U12	U13	U23
C1	0.0151 (5)	0.0196 (6)	0.0210 (6)	0.0028 (4)	−0.0008 (4)	0.0010 (5)
C2	0.0222 (6)	0.0177 (6)	0.0213 (6)	0.0026 (5)	0.0002 (5)	−0.0012 (5)
C3	0.0191 (6)	0.0219 (6)	0.0207 (6)	−0.0031 (5)	−0.0022 (4)	−0.0009 (5)
C4	0.0146 (5)	0.0261 (7)	0.0227 (6)	0.0016 (5)	−0.0013 (4)	−0.0001 (5)
C5	0.0172 (6)	0.0199 (6)	0.0204 (6)	0.0031 (5)	0.0011 (4)	−0.0008 (5)
C6	0.0163 (5)	0.0171 (6)	0.0170 (5)	−0.0003 (4)	−0.0008 (4)	0.0010 (5)
C7	0.0202 (6)	0.0185 (6)	0.0191 (6)	−0.0007 (5)	−0.0006 (4)	−0.0001 (5)
C8	0.0194 (6)	0.0224 (7)	0.0192 (6)	−0.0037 (5)	−0.0019 (4)	0.0009 (5)
C9	0.0209 (6)	0.0207 (6)	0.0206 (6)	−0.0033 (5)	−0.0025 (5)	−0.0011 (5)
C10	0.0204 (6)	0.0216 (6)	0.0197 (6)	−0.0032 (5)	−0.0035 (5)	−0.0012 (5)
N1	0.0197 (5)	0.0231 (6)	0.0241 (6)	−0.0047 (4)	−0.0043 (4)	−0.0052 (5)
O1	0.0170 (5)	0.0292 (6)	0.0402 (6)	0.0085 (4)	−0.0070 (4)	−0.0111 (5)
O2	0.0199 (5)	0.0217 (5)	0.0250 (5)	−0.0030 (4)	−0.0048 (4)	−0.0048 (4)
O3	0.0250 (5)	0.0231 (5)	0.0330 (5)	0.0006 (4)	−0.0067 (4)	−0.0060 (4)

C1—O1	1.3583 (15)	C7—H7	0.958 (18)
C1—C2	1.3935 (18)	C8—O3	1.1985 (17)
C1—C6	1.4105 (18)	C8—O2	1.3784 (16)
C2—C3	1.3857 (17)	C8—C9	1.5047 (18)
C2—H2	0.9300	C9—C10	1.5255 (18)
C3—C4	1.3943 (19)	C9—H9A	0.9700
C3—H3	0.9300	C9—H9B	0.9700
C4—C5	1.3850 (18)	C10—C10i	1.526 (2)
C4—H4	0.9300	C10—H10B	0.9700
C5—C6	1.4054 (17)	C10—H10A	0.9700
C5—H5	0.9300	N1—O2	1.4226 (14)
C6—C7	1.4639 (17)	O1—H1	0.91 (3)
C7—N1	1.2782 (17)
O1—C1—C2	116.85 (12)	C6—C7—H7	119.1 (10)
O1—C1—C6	123.07 (12)	O3—C8—O2	123.73 (12)
C2—C1—C6	120.08 (11)	O3—C8—C9	126.36 (12)
C3—C2—C1	120.10 (12)	O2—C8—C9	109.91 (11)
C3—C2—H2	120.0	C8—C9—C10	111.35 (11)
C1—C2—H2	120.0	C8—C9—H9A	109.4
C2—C3—C4	120.75 (12)	C10—C9—H9A	109.4
C2—C3—H3	119.6	C8—C9—H9B	109.4
C4—C3—H3	119.6	C10—C9—H9B	109.4
C5—C4—C3	119.31 (11)	H9A—C9—H9B	108.0
C5—C4—H4	120.3	C9—C10—C10i	111.85 (14)
C3—C4—H4	120.3	C9—C10—H10B	109.2
C4—C5—C6	121.19 (12)	C10i—C10—H10B	109.2
C4—C5—H5	119.4	C9—C10—H10A	109.2
C6—C5—H5	119.4	C10i—C10—H10A	109.2
C5—C6—C1	118.56 (11)	H10B—C10—H10A	107.9
C5—C6—C7	119.65 (12)	C7—N1—O2	112.42 (11)
C1—C6—C7	121.79 (11)	C1—O1—H1	109.0 (15)
N1—C7—C6	118.03 (12)	C8—O2—N1	110.45 (10)
N1—C7—H7	122.9 (10)
O1—C1—C2—C3	178.68 (12)	C2—C1—C6—C7	179.53 (12)
C6—C1—C2—C3	−1.30 (19)	C5—C6—C7—N1	175.82 (12)
C1—C2—C3—C4	1.0 (2)	C1—C6—C7—N1	−3.07 (19)
C2—C3—C4—C5	−0.1 (2)	O3—C8—C9—C10	0.66 (19)
C3—C4—C5—C6	−0.6 (2)	O2—C8—C9—C10	179.67 (10)
C4—C5—C6—C1	0.30 (19)	C8—C9—C10—C10i	177.66 (13)
C4—C5—C6—C7	−178.63 (12)	C6—C7—N1—O2	−179.06 (10)
O1—C1—C6—C5	−179.35 (12)	O3—C8—O2—N1	−2.57 (18)
C2—C1—C6—C5	0.63 (18)	C9—C8—O2—N1	178.39 (10)
O1—C1—C6—C7	−0.4 (2)	C7—N1—O2—C8	178.03 (11)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1	0.91 (3)	1.79 (3)	2.5836 (15)	144 (2)
C4—H4···O1ii	0.93	2.45	3.1874 (17)	136
C2—H2···Cg1iii	0.93	2.75	3.4659 (14)	134

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	0.91 (3)	1.79 (3)	2.5836 (15)	144 (2)
C4—H4⋯O1i	0.93	2.45	3.1874 (17)	136
C2—H2⋯Cg1ii	0.93	2.75	3.4659 (14)	134

Symmetry codes: (i) ; (ii) . Cg1 is the centroid of the C1–C6 benzene ring.