(E,E)-1,2-Bis[3-meth­­oxy-4-(prop-2-yn-1-yl­­oxy)benzyl­­idene]hydrazine

The complete mol­ecule in the title compound, C₂₂H₂₀N₂O₄, is generated by the application of an inversion centre. With the exception of the terminal acetyl­ene groups [C—O—C—C = −78.02 (17)°], the remaining atoms constituting the mol­ecule are essentially coplanar. The configuration around the C=N bond [1.282 (2) Å] is E. The formation of supra­molecular chains mediated by C—H⋯O inter­actions, occurring between methyl­ene H and meth­oxy O atoms, is the most notable feature of the crystal packing.

Related literature

For background to the study see: Xu et al. (1997); Zheng et al. (2005); Kundu et al. (2005). For additional analysis, see: Spek (2009).

Experimental

Crystal data

• C₂₂H₂₀N₂O₄

• M_r = 376.40

• Monoclinic, P 2₁ /n

• a = 4.4840 (3) Å

• b = 14.4636 (8) Å

• c = 14.3939 (9) Å

• β = 91.674 (4)°

• V = 933.11 (10) ų

• Z = 2

• Mo Kα radiation

• μ = 0.09 mm⁻¹

• T = 100 K

• 0.25 × 0.11 × 0.07 mm

Data collection

• Bruker SMART APEX CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996) T_min = 0.368, T_max = 0.746

• 8574 measured reflections

• 2138 independent reflections

• 1625 reflections with I > 2σ(I)

• R_int = 0.069

Refinement

• R[F² > 2σ(F²)] = 0.046

• wR(F²) = 0.124

• S = 1.05

• 2138 reflections

• 128 parameters

• H-atom parameters constrained

• Δρ_max = 0.26 e Å⁻³

• Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8a⋯O2^i	0.99	2.36	3.255 (2)	150
Symmetry code: (i) -x+3, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

S1. Comment

Molecules combining an azine functionality and/or a diimine linkage have been investigated in terms of their crystallography and coordination chemistry (Xu et al., 1997; Zheng et al., 2005; Kundu et al., 2005). In this connection the title compound, (I), was studied.

The molecule of (I), Fig. 1, is centrosymmetric around the central azine [N1—N1ⁱ = 1.413 (2) Å] bond; symmetry operation i: 1 - x, 1 - y, -z. The configuration around the C1═N1 bond [1.282 (2) Å] is E. With the exception of the terminal acetylene group, the molecule is essentially planar as seen in the values of the N1—C1—C2—C7 and C11—O2—C6—C5 torsion angles of 2.9 (2) and 177.04 (14) °, respectively. By contrast, the torsion angle C5—O1—C8—C9 of -78.02 (17) ° indicates the acetylene group is almost perpendicular to the rest of the molecule.

The most prominent feature of the crystal packing is the presence of C—H···O interactions, occurring between methylene-H and the methoxy-O atoms, which serve to link molecules into supramolecular chains mediated by centrosymmetric 12-membered {···HCOC₂O}₂ synthons, Table 1 and Fig. 2. Chains pack in the ac plane and interdigitate along the b axis., Fig. 3. Each acetylene-H atom is orientated towards an imino-N atom, being separated by 2.77 Å, i.e. outside the standard criteria to be considered significant (Spek, 2009).

Related literature

For background to the study see: Xu et al. (1997); Zheng et al. (2005); Kundu et al. (2005). For additional analysis, see: Spek (2009).

S2. Experimental

Vanillinazine (2.0 g, 6.7 mmol) in dry acetone and anhydrous K₂CO₃ (1.84 g, 13.3 mmol) was stirred at room temperature for about 20 min. Then, an excess of propargyl bromide (1.74 g, 14.7 mmol) was added drop wise. The mixture was refluxed for 48 h. The solvent was evaporated under reduced pressure and the product extracted with 100 ml diethyl ether. The organic layer was washed with brine and dried over MgSO₄. The yellow compound was recrystallized from ethyl acetate/methanol (1/1) solution to yield yellow needles of (I); yield 72% and M.pt. 460 K.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation with U_iso(H) = 1.2–1.5U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. The molecular structure of centrosymmetric compound (I) showing displacement ellipsoids at the 50% probability level. Symmetry code i: 1 - x, 1 - y, -z.
	Fig. 2. A view of the supramolecular chains in (I) mediated by C—H···O interactions (orange dashed lines) and their aggregation into layers in the ac plane.
	Fig. 3. A view in projection down the a axis of the unit-cell contents for (I); the C—H···O interactions are shown as orange dashed lines.

(E,E)-1,2-Bis[3-methoxy-4-(prop-2-yn-1-yloxy)benzylidene]hydrazine

Crystal data

C22H20N2O4	F(000) = 396
Mr = 376.40	Dx = 1.340 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1658 reflections
a = 4.4840 (3) Å	θ = 2.8–29.5°
b = 14.4636 (8) Å	µ = 0.09 mm^−1
c = 14.3939 (9) Å	T = 100 K
β = 91.674 (4)°	Needle, yellow
V = 933.11 (10) Å^3	0.25 × 0.11 × 0.07 mm
Z = 2

Data collection

Bruker SMART APEX CCD diffractometer	2138 independent reflections
Radiation source: fine-focus sealed tube	1625 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.069
ω scans	θmax = 27.5°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→5
Tmin = 0.368, Tmax = 0.746	k = −18→18
8574 measured reflections	l = −18→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.124	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0481P)^2 + 0.2035P] where P = (Fo^2 + 2Fc^2)/3
2138 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.26 e Å^−3
0 restraints	Δρmin = −0.25 e Å^−3

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 (Ų)

	x	y	z	Uiso*/Ueq
O1	1.2641 (2)	0.54779 (7)	0.43315 (7)	0.0201 (3)
O2	1.3374 (2)	0.41802 (7)	0.31509 (8)	0.0218 (3)
N1	0.5998 (3)	0.49139 (8)	0.03789 (9)	0.0204 (3)
C1	0.5930 (3)	0.55648 (10)	0.09829 (11)	0.0195 (4)
H1	0.4638	0.6075	0.0867	0.023*
C2	0.7742 (3)	0.55572 (10)	0.18375 (11)	0.0187 (3)
C3	0.7351 (3)	0.62536 (10)	0.24843 (11)	0.0201 (4)
H3	0.5955	0.6733	0.2351	0.024*
C4	0.8968 (3)	0.62633 (10)	0.33254 (11)	0.0192 (3)
H4	0.8694	0.6750	0.3758	0.023*
C5	1.0972 (3)	0.55612 (9)	0.35270 (10)	0.0170 (3)
C6	1.1383 (3)	0.48469 (9)	0.28727 (11)	0.0178 (3)
C7	0.9810 (3)	0.48486 (9)	0.20414 (11)	0.0182 (3)
H7	1.0117	0.4370	0.1602	0.022*
C8	1.2080 (4)	0.61172 (10)	0.50702 (11)	0.0209 (4)
H8A	1.2888	0.5857	0.5662	0.025*
H8B	0.9898	0.6189	0.5128	0.025*
C9	1.3423 (4)	0.70363 (10)	0.49229 (11)	0.0214 (4)
C10	1.4542 (4)	0.77718 (11)	0.48483 (12)	0.0262 (4)
H10	1.5441	0.8363	0.4788	0.031*
C11	1.3762 (4)	0.34187 (10)	0.25333 (12)	0.0255 (4)
H11A	1.1830	0.3121	0.2405	0.038*
H11B	1.5142	0.2971	0.2821	0.038*
H11C	1.4578	0.3642	0.1950	0.038*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0245 (6)	0.0180 (5)	0.0174 (6)	0.0022 (4)	−0.0053 (5)	−0.0022 (4)
O2	0.0261 (6)	0.0161 (5)	0.0228 (6)	0.0055 (4)	−0.0061 (5)	−0.0030 (4)
N1	0.0202 (7)	0.0225 (6)	0.0182 (7)	−0.0017 (5)	−0.0047 (6)	0.0031 (5)
C1	0.0185 (8)	0.0176 (7)	0.0223 (8)	−0.0017 (6)	−0.0020 (7)	0.0035 (6)
C2	0.0180 (8)	0.0171 (7)	0.0209 (8)	−0.0036 (6)	−0.0014 (7)	0.0025 (6)
C3	0.0184 (8)	0.0160 (7)	0.0260 (9)	0.0001 (6)	−0.0019 (7)	0.0029 (6)
C4	0.0221 (8)	0.0150 (7)	0.0207 (8)	−0.0009 (6)	0.0004 (7)	−0.0012 (6)
C5	0.0176 (8)	0.0162 (7)	0.0171 (8)	−0.0029 (6)	−0.0013 (6)	0.0016 (5)
C6	0.0172 (8)	0.0132 (7)	0.0230 (8)	−0.0006 (6)	−0.0007 (6)	0.0023 (6)
C7	0.0195 (8)	0.0148 (7)	0.0202 (8)	−0.0019 (6)	−0.0002 (6)	−0.0013 (5)
C8	0.0259 (9)	0.0211 (7)	0.0154 (8)	0.0006 (6)	−0.0024 (7)	−0.0026 (6)
C9	0.0245 (9)	0.0227 (8)	0.0169 (8)	0.0031 (6)	−0.0020 (7)	−0.0032 (6)
C10	0.0325 (10)	0.0215 (8)	0.0244 (9)	0.0001 (7)	−0.0031 (8)	−0.0031 (6)
C11	0.0293 (9)	0.0176 (7)	0.0293 (9)	0.0034 (6)	−0.0056 (8)	−0.0055 (6)

Geometric parameters (Å, º)

O1—C5	1.3655 (17)	C4—H4	0.9500
O1—C8	1.4368 (18)	C5—C6	1.414 (2)
O2—C6	1.3664 (16)	C6—C7	1.371 (2)
O2—C11	1.4292 (18)	C7—H7	0.9500
N1—C1	1.282 (2)	C8—C9	1.477 (2)
N1—N1^i	1.413 (2)	C8—H8A	0.9900
C1—C2	1.454 (2)	C8—H8B	0.9900
C1—H1	0.9500	C9—C10	1.182 (2)
C2—C3	1.386 (2)	C10—H10	0.9500
C2—C7	1.407 (2)	C11—H11A	0.9800
C3—C4	1.393 (2)	C11—H11B	0.9800
C3—H3	0.9500	C11—H11C	0.9800
C4—C5	1.381 (2)
C5—O1—C8	117.87 (11)	O2—C6—C5	114.66 (13)
C6—O2—C11	116.87 (11)	C7—C6—C5	120.43 (13)
C1—N1—N1^i	111.53 (15)	C6—C7—C2	120.15 (14)
N1—C1—C2	122.96 (14)	C6—C7—H7	119.9
N1—C1—H1	118.5	C2—C7—H7	119.9
C2—C1—H1	118.5	O1—C8—C9	113.08 (13)
C3—C2—C7	118.98 (14)	O1—C8—H8A	109.0
C3—C2—C1	118.95 (13)	C9—C8—H8A	109.0
C7—C2—C1	122.03 (14)	O1—C8—H8B	109.0
C2—C3—C4	121.22 (14)	C9—C8—H8B	109.0
C2—C3—H3	119.4	H8A—C8—H8B	107.8
C4—C3—H3	119.4	C10—C9—C8	176.86 (17)
C5—C4—C3	119.61 (14)	C9—C10—H10	180.0
C5—C4—H4	120.2	O2—C11—H11A	109.5
C3—C4—H4	120.2	O2—C11—H11B	109.5
O1—C5—C4	125.46 (13)	H11A—C11—H11B	109.5
O1—C5—C6	114.94 (12)	O2—C11—H11C	109.5
C4—C5—C6	119.60 (13)	H11A—C11—H11C	109.5
O2—C6—C7	124.90 (13)	H11B—C11—H11C	109.5
N1^i—N1—C1—C2	179.28 (15)	C11—O2—C6—C5	177.04 (14)
N1—C1—C2—C3	−174.95 (15)	O1—C5—C6—O2	0.4 (2)
N1—C1—C2—C7	2.9 (2)	C4—C5—C6—O2	−178.85 (13)
C7—C2—C3—C4	0.2 (2)	O1—C5—C6—C7	179.38 (13)
C1—C2—C3—C4	178.11 (14)	C4—C5—C6—C7	0.1 (2)
C2—C3—C4—C5	−0.9 (2)	O2—C6—C7—C2	178.03 (14)
C8—O1—C5—C4	6.4 (2)	C5—C6—C7—C2	−0.8 (2)
C8—O1—C5—C6	−172.80 (13)	C3—C2—C7—C6	0.7 (2)
C3—C4—C5—O1	−178.48 (15)	C1—C2—C7—C6	−177.22 (15)
C3—C4—C5—C6	0.7 (2)	C5—O1—C8—C9	−78.02 (17)
C11—O2—C6—C7	−1.8 (2)	O1—C8—C9—C10	−136 (3)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8a···O2^ii	0.99	2.36	3.255 (2)	150

Symmetry code: (ii) −x+3, −y+1, −z+1.