1,2-Bis(2-furylmethyl­ene)hydrazine

Crystals of the title compound, C₁₀H₈N₂O₂, were obtained from a condensation reaction of hydrazine hydrate with furfural. In the crystal structure, the mol­ecule is centrosymmetric and almost planar and the furan rings are parallel by symmetry.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.105
• Data-to-parameter ratio = 12.8

checkCIF/PLATON results

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PLAT230_ALERT_2_C Hirshfeld Test Diff for    C1     --  C2      ..       5.11 su
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S1. Comment

Schiff bases have been studied for decades (Casellato & Vigato 1977) and they are still one of the most prevalent mixed-donor ligands in coordination chemistry, with numerous applications including single-molecule magnetism, materials science and catalysis. Here, the synthsis and crystal structure of the title compound (I) are reported.

The molecule of (I) is centrosymmetric, with the midpoint of the N—N bond located on the inversion center. The C5—N1 double bond distance of 1.272 (2) Å is shorter than the C═N bond distance found in related hydrazone structures, i.e. 1.295 (2) Å in (E)-3-methoxyacetophenone 4-nitrophenylhydrazone (Fan et al., 2008), 1.298 (2) Å in (E)-2-furylmethylketone 2,4-dinitrophenylhydrazone (Shan, Tian et al., 2008) and 1.293 (2) Å in benzylideneacetone 2,4-dinitrophenylhydrazone (Shan et al., 2004). It is indistinguishable from the length of 1.273 (1) Å in 2-methylbenzaldehyde 2-methylbenzylidenehydrazone (Shan, Wang et al., 2008).

Related literature

For background, see: Casellato & Vigato (1977); For related structures, see: Fan et al. (2008); Shan et al. (2004); Shan, Tian et al. (2008); Shan, Wang et al. (2008).

S2. Experimental

Hydrazine hydrate (35% solution in water, 0.71 g, 5 mmol) and furfural (0.96 g, 10 mmol) were mixed, at the same time adding 2 or 3 drops of formic acid, and stirred at room temperature in 30 ml of ethanol solution for 2 days, and then the filtrate was kept open to slowly evaporate for a few days, depositing yellow blocks of (I).

S3. Refinement

The H atoms attached were placed in geometrically idealized positions (C—H = 0.93 Å) and refined as riding with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXTL/PC (Sheldrick, 2008).

Figures

Fig. 1. A view of the molecular structure of (I) with displacement ellipsoids for the non-hydrogen atoms drawn at the 30% probability level (arbitrary spheres for the H atoms). The unlabelled atoms are generated by the symmetry operation (1-x, 2-y, -z).

1,2-Bis(2-furylmethylene)hydrazine

Crystal data

C10H8N2O2	F(000) = 392
Mr = 188.18	Dx = 1.332 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 5207 reflections
a = 6.877 (2) Å	θ = 2.6–25.3°
b = 8.996 (3) Å	µ = 0.10 mm^−1
c = 15.171 (4) Å	T = 298 K
V = 938.6 (5) Å^3	Block, yellow
Z = 4	0.50 × 0.40 × 0.40 mm

Data collection

Bruker SMART 1K CCD diffractometer	829 independent reflections
Radiation source: fine-focus sealed tube	677 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.081
ω scans	θmax = 25.3°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −8→8
Tmin = 0.954, Tmax = 0.963	k = −10→10
4129 measured reflections	l = −18→9

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0662P)^2] where P = (Fo^2 + 2Fc^2)/3
829 reflections	(Δ/σ)max < 0.001
65 parameters	Δρmax = 0.16 e Å^−3
0 restraints	Δρmin = −0.25 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	−0.0467 (2)	0.88870 (18)	0.18436 (11)	0.0736 (5)
H1	−0.0937	0.8074	0.2157	0.088*
C2	−0.1336 (2)	1.01970 (19)	0.18094 (10)	0.0719 (5)
H2	−0.2492	1.0466	0.2084	0.086*
C3	−0.0168 (2)	1.10963 (17)	0.12769 (10)	0.0642 (5)
H3	−0.0400	1.2085	0.1131	0.077*
C4	0.13456 (19)	1.02755 (14)	0.10149 (8)	0.0529 (4)
C5	0.2964 (2)	1.06191 (15)	0.04628 (9)	0.0566 (4)
H5	0.3049	1.1570	0.0225	0.068*
N1	0.42950 (18)	0.96866 (13)	0.02805 (8)	0.0613 (4)
O1	0.12017 (16)	0.88799 (10)	0.13632 (7)	0.0669 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0695 (10)	0.0698 (11)	0.0815 (11)	−0.0135 (8)	0.0114 (9)	0.0137 (8)
C2	0.0637 (10)	0.0800 (12)	0.0721 (11)	0.0049 (8)	0.0084 (7)	0.0085 (8)
C3	0.0722 (11)	0.0589 (10)	0.0616 (9)	0.0093 (7)	0.0038 (7)	0.0082 (7)
C4	0.0639 (9)	0.0452 (8)	0.0496 (7)	−0.0049 (6)	−0.0044 (6)	0.0007 (6)
C5	0.0690 (10)	0.0485 (8)	0.0522 (8)	−0.0055 (7)	0.0007 (7)	0.0013 (6)
N1	0.0649 (8)	0.0541 (8)	0.0649 (8)	−0.0033 (6)	0.0084 (5)	0.0045 (5)
O1	0.0698 (8)	0.0479 (7)	0.0830 (8)	−0.0029 (5)	0.0078 (5)	0.0057 (4)

Geometric parameters (Å, º)

C1—C2	1.322 (2)	C3—H3	0.9300
C1—O1	1.359 (2)	C4—O1	1.3657 (16)
C1—H1	0.9300	C4—C5	1.427 (2)
C2—C3	1.397 (2)	C5—N1	1.2721 (18)
C2—H2	0.9300	C5—H5	0.9300
C3—C4	1.3364 (19)	N1—N1^i	1.408 (2)
C2—C1—O1	111.39 (14)	C3—C4—O1	109.66 (12)
C2—C1—H1	124.3	C3—C4—C5	131.47 (13)
O1—C1—H1	124.3	O1—C4—C5	118.87 (12)
C1—C2—C3	106.18 (15)	N1—C5—C4	123.10 (13)
C1—C2—H2	126.9	N1—C5—H5	118.4
C3—C2—H2	126.9	C4—C5—H5	118.4
C4—C3—C2	107.45 (14)	C5—N1—N1^i	111.29 (15)
C4—C3—H3	126.3	C1—O1—C4	105.32 (12)
C2—C3—H3	126.3
O1—C1—C2—C3	−0.05 (19)	O1—C4—C5—N1	−0.4 (2)
C1—C2—C3—C4	0.23 (18)	C4—C5—N1—N1^i	179.64 (14)
C2—C3—C4—O1	−0.32 (17)	C2—C1—O1—C4	−0.14 (18)
C2—C3—C4—C5	179.42 (15)	C3—C4—O1—C1	0.29 (16)
C3—C4—C5—N1	179.91 (15)	C5—C4—O1—C1	−179.49 (12)

Symmetry code: (i) −x+1, −y+2, −z.