4,4'-Dimeth-oxy-2,2'-[(butane-1,4-diyldi-oxy)bis-(nitrilo-methyl-idyne)]diphenol.

The title Schiff base bis-oxime compound, C(20)H(24)N(2)O(6), lies across an inversion centre and adopts an E configuration with respect to the C=N bond. In the mol-ecule, the oxime group is roughly coplanar with the benzene ring, forming a dihedral angle of 1.77 (2)°. An intra-molecular O-H⋯N hydrogen bond forms a six-membered ring with an S(6) motif. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

Related literature

For applications of Schiff base compounds, see: Dong & Ding (2008 ▶); Dong et al. (2007 ▶, 2009b ▶); Koizumi et al. (2005 ▶); Lu et al. (2006 ▶). For the synthesis, see: Dong et al. (2009a ▶).

Experimental

Crystal data

C20H24N2O6

M = 388.41

Monoclinic,

a = 4.7310 (4) Å

b = 17.1418 (16) Å

c = 12.2648 (12) Å

β = 90.981 (1)°

V = 994.50 (16) Å3

Z = 2

Mo Kα radiation

μ = 0.10 mm−1

T = 298 K

0.50 × 0.22 × 0.18 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer

4976 measured reflections

1765 independent reflections

834 reflections with I > 2σ(I)

R int = 0.069

Refinement

R[F 2 > 2σ(F 2)] = 0.050

wR(F 2) = 0.149

S = 1.02

1765 reflections

128 parameters

H-atom parameters constrained

Δρmax = 0.17 e Å−3

Δρmin = −0.20 e Å−3

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

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810040511/xu5040sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810040511/xu5040Isup2.hkl

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

C20H24N2O6	F(000) = 412
Mr = 388.41	Dx = 1.297 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 796 reflections
a = 4.7310 (4) Å	θ = 2.4–24.5°
b = 17.1418 (16) Å	µ = 0.10 mm−1
c = 12.2648 (12) Å	T = 298 K
β = 90.981 (1)°	Needle, pale-yellow
V = 994.50 (16) Å3	0.50 × 0.22 × 0.18 mm
Z = 2

Bruker SMART 1000 CCD area-detector diffractometer	834 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.069
graphite	θmax = 25.0°, θmin = 2.0°
φ and ω scans	h = −5→5
4976 measured reflections	k = −20→18
1765 independent reflections	l = −13→14

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.149	H-atom parameters constrained
S = 1.02	w = 1/[σ2(Fo2) + (0.0562P)2] where P = (Fo2 + 2Fc2)/3
1765 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.17 e Å−3
0 restraints	Δρmin = −0.20 e Å−3

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
N1	0.4274 (5)	0.32971 (13)	0.62366 (17)	0.0426 (7)
O1	0.2476 (4)	0.37363 (10)	0.55503 (13)	0.0495 (6)
O2	0.6869 (5)	0.27865 (12)	0.80239 (14)	0.0626 (7)
H2	0.5744	0.3054	0.7672	0.094*
O3	1.2686 (5)	0.07207 (12)	0.54439 (19)	0.0669 (7)
C1	0.1003 (7)	0.43013 (16)	0.6187 (2)	0.0494 (9)
H1A	0.2336	0.4642	0.6562	0.059*
H1B	−0.0147	0.4043	0.6726	0.059*
C2	−0.0830 (7)	0.47634 (15)	0.5412 (2)	0.0486 (9)
H2A	−0.1998	0.5116	0.5829	0.058*
H2B	−0.2080	0.4408	0.5021	0.058*
C3	0.5649 (7)	0.27896 (16)	0.5696 (2)	0.0407 (8)
H3	0.5341	0.2752	0.4947	0.049*
C4	0.7676 (6)	0.22699 (15)	0.6220 (2)	0.0381 (7)
C5	0.8222 (7)	0.22862 (17)	0.7338 (2)	0.0453 (8)
C6	1.0185 (8)	0.17800 (19)	0.7794 (2)	0.0586 (10)
H6	1.0521	0.1781	0.8544	0.070*
C7	1.1646 (8)	0.12723 (18)	0.7136 (3)	0.0589 (10)
H7	1.2999	0.0942	0.7444	0.071*
C8	1.1118 (7)	0.12492 (17)	0.6016 (2)	0.0500 (9)
C9	0.9145 (6)	0.17495 (16)	0.5571 (2)	0.0420 (8)
H9	0.8787	0.1740	0.4823	0.050*
C10	1.2332 (8)	0.07222 (19)	0.4288 (3)	0.0747 (12)
H10A	1.0414	0.0589	0.4099	0.112*
H10B	1.3588	0.0347	0.3975	0.112*
H10C	1.2757	0.1232	0.4010	0.112*

	U11	U22	U33	U12	U13	U23
N1	0.0462 (19)	0.0427 (14)	0.0387 (13)	0.0063 (13)	−0.0049 (12)	0.0047 (12)
O1	0.0589 (16)	0.0474 (12)	0.0419 (11)	0.0167 (12)	−0.0083 (11)	−0.0002 (9)
O2	0.0703 (18)	0.0798 (15)	0.0374 (11)	0.0180 (14)	−0.0085 (11)	−0.0050 (11)
O3	0.0670 (19)	0.0583 (14)	0.0752 (16)	0.0223 (14)	−0.0005 (14)	0.0021 (12)
C1	0.055 (2)	0.0477 (19)	0.0452 (18)	0.0095 (17)	0.0034 (16)	0.0005 (15)
C2	0.049 (2)	0.0423 (18)	0.0547 (19)	0.0086 (16)	0.0037 (16)	0.0033 (13)
C3	0.048 (2)	0.0414 (16)	0.0321 (14)	−0.0018 (17)	−0.0055 (14)	0.0026 (14)
C4	0.040 (2)	0.0387 (16)	0.0355 (15)	0.0004 (16)	−0.0056 (14)	0.0095 (13)
C5	0.050 (2)	0.0496 (19)	0.0362 (16)	0.0034 (17)	−0.0045 (15)	0.0030 (14)
C6	0.065 (3)	0.072 (2)	0.0387 (17)	0.001 (2)	−0.0138 (17)	0.0172 (17)
C7	0.052 (2)	0.061 (2)	0.064 (2)	0.010 (2)	−0.0105 (19)	0.0201 (18)
C8	0.053 (2)	0.0422 (18)	0.0547 (19)	0.0016 (18)	−0.0003 (18)	0.0074 (16)
C9	0.048 (2)	0.0396 (16)	0.0382 (16)	0.0009 (16)	−0.0062 (15)	0.0078 (13)
C10	0.083 (3)	0.068 (2)	0.074 (3)	0.017 (2)	0.018 (2)	−0.0021 (19)

N1—C3	1.278 (3)	C3—H3	0.9300
N1—O1	1.405 (3)	C4—C9	1.390 (4)
O1—C1	1.432 (3)	C4—C5	1.391 (4)
O2—C5	1.368 (3)	C5—C6	1.382 (4)
O2—H2	0.8200	C6—C7	1.381 (4)
O3—C8	1.372 (3)	C6—H6	0.9300
O3—C10	1.425 (3)	C7—C8	1.392 (4)
C1—C2	1.501 (3)	C7—H7	0.9300
C1—H1A	0.9700	C8—C9	1.374 (4)
C1—H1B	0.9700	C9—H9	0.9300
C2—C2i	1.524 (5)	C10—H10A	0.9600
C2—H2A	0.9700	C10—H10B	0.9600
C2—H2B	0.9700	C10—H10C	0.9600
C3—C4	1.451 (4)
C3—N1—O1	111.2 (2)	O2—C5—C6	117.6 (3)
N1—O1—C1	109.33 (19)	O2—C5—C4	122.5 (3)
C5—O2—H2	109.5	C6—C5—C4	119.9 (3)
C8—O3—C10	116.9 (2)	C7—C6—C5	119.9 (3)
O1—C1—C2	107.0 (2)	C7—C6—H6	120.0
O1—C1—H1A	110.3	C5—C6—H6	120.0
C2—C1—H1A	110.3	C6—C7—C8	120.8 (3)
O1—C1—H1B	110.3	C6—C7—H7	119.6
C2—C1—H1B	110.3	C8—C7—H7	119.6
H1A—C1—H1B	108.6	O3—C8—C9	125.3 (3)
C1—C2—C2i	113.7 (3)	O3—C8—C7	115.7 (3)
C1—C2—H2A	108.8	C9—C8—C7	118.9 (3)
C2i—C2—H2A	108.8	C8—C9—C4	121.1 (3)
C1—C2—H2B	108.8	C8—C9—H9	119.5
C2i—C2—H2B	108.8	C4—C9—H9	119.5
H2A—C2—H2B	107.7	O3—C10—H10A	109.5
N1—C3—C4	121.8 (3)	O3—C10—H10B	109.5
N1—C3—H3	119.1	H10A—C10—H10B	109.5
C4—C3—H3	119.1	O3—C10—H10C	109.5
C9—C4—C5	119.4 (3)	H10A—C10—H10C	109.5
C9—C4—C3	118.3 (2)	H10B—C10—H10C	109.5
C5—C4—C3	122.3 (3)
C3—N1—O1—C1	−179.4 (2)	C4—C5—C6—C7	1.5 (5)
N1—O1—C1—C2	178.8 (2)	C5—C6—C7—C8	−1.6 (5)
O1—C1—C2—C2i	−64.3 (4)	C10—O3—C8—C9	3.4 (5)
O1—N1—C3—C4	179.2 (2)	C10—O3—C8—C7	−175.7 (3)
N1—C3—C4—C9	−178.2 (3)	C6—C7—C8—O3	−179.8 (3)
N1—C3—C4—C5	0.7 (5)	C6—C7—C8—C9	1.0 (5)
C9—C4—C5—O2	179.6 (3)	O3—C8—C9—C4	−179.5 (3)
C3—C4—C5—O2	0.7 (5)	C7—C8—C9—C4	−0.3 (5)
C9—C4—C5—C6	−0.8 (4)	C5—C4—C9—C8	0.3 (4)
C3—C4—C5—C6	−179.7 (3)	C3—C4—C9—C8	179.2 (3)
O2—C5—C6—C7	−178.9 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···N1	0.82	1.93	2.643 (2)	145
C3—H3···O2ii	0.93	2.65	3.481 (3)	150
C9—H9···O2ii	0.93	2.51	3.382 (3)	157
C10—H10A···O3iii	0.96	2.74	3.448 (4)	131

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯N1	0.82	1.93	2.643 (2)	145
C3—H3⋯O2i	0.93	2.65	3.481 (3)	150
C9—H9⋯O2i	0.93	2.51	3.382 (3)	157
C10—H10A⋯O3ii	0.96	2.74	3.448 (4)	131

Symmetry codes: (i) ; (ii) .