4-Fluoro­benzaldehyde salicylhydrazone

Zhang, Y.; Zhang, S.-P.; Wu, Y.-Y.; Shao, S.-C.

doi:10.1107/S1600536805040420

4-Fluorobenzaldehyde salicylhydrazone

Y. Zhang, S.-P. Zhang, Y.-Y. Wu and S.-C. Shao

The title compound, C₁₄H₁₁FN₂O₂, crystallizes with two molecules in the asymmetric unit. Both molecules are roughly planar and adopts a trans configuration with respect to the C=N double bond. In the crystal structure, intermolecular O—H

O and N—H

O hydrogen bonds result in the formation of sheets parallel to the ac plane.

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805040420/dn6282sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536805040420/dn6282Isup2.hkl Contains datablock I

CCDC reference: 296556

checkCIF report

Key indicators

Single-crystal X-ray study
T = 298 K
Mean (C-C) = 0.004 Å
R factor = 0.054
wR factor = 0.148
Data-to-parameter ratio = 12.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         49 Perc.
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C12

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

Comment top

Schiff base compounds have been of great interest for many years. These compounds play an important role in the development of coordination chemistry related to catalysis and enzymatic reactions (Brunner et al., 1983), magnetism and molecular architectures (Miller et al., 2000). The deprotonated hydroxyl group of the salicylhydrazone will sometimes cause the N atom of the hydrazone to become more electron-rich as a result of conjugation effects, and the N atom can thus coordinate more strongly (Bansse et al., 1998). As an extension of work on the structural characterization of salicylhydrazone Schiff base compounds (Ma et al., 2005), we report here the crystal structure of (I), a new salicylhydrazone with 4-fluorobenzaldehyde.

In the title compound, (I), which crystallizes with two molecules in the asymmetric unit (Fig. 1), C—N bonds in the hydrazone units are rather short (Table 1) owing to conjugation effects (Ma et al., 2005). All other bond lengths are within normal ranges (Allen, 2002). The dihedral angles between the two benzene rings are 7.3 (2) ° and 18.7 (1) ° in the two molecules.

The occurrence of O—H···O hydrogen bonds results in the formation of infinite chains which are linked by N—H···O hydrogen bonds, forming sheets parallel to the ac plane (Table 2 and Fig. 2).

Experimental top

The reagents were commercial products and were used without further purification. 4-Fluorobenzaldehyde (0.2 mmol, 28 mg) and 2-hydroxybenzohydrazide (0.2 mmol, 30.4 mg) were dissolved in methanol (10 ml). The mixture was stirred at room temperature for about 10 min to give a clear yellow solution. The solution was set aside for 8 d to allow slow evaporation of the solvent. Large colourless block-shaped crystals separated; these were collected and washed three times with water.

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII(Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: SHELXL97.

Figures top

	Fig. 1. The structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. The O—H···O hydrogen contact is represented by dashed line.
	Fig. 2. The crystal packing of (I), showing the formation of sheets. O—H···O and N—H···O hydrogen bonds are represented by dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity.

4-Fluorobenzaldehyde salicylhydrazone top

Crystal data top

C₁₄H₁₁FN₂O₂	F(000) = 1072
M_r = 258.25	D_x = 1.383 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3063 reflections
a = 4.9532 (4) Å	θ = 4.7–41.4°
b = 47.867 (4) Å	µ = 0.10 mm⁻¹
c = 10.7392 (9) Å	T = 298 K
β = 102.953 (2)°	Prism, colourless
V = 2481.4 (4) Å³	0.35 × 0.18 × 0.12 mm
Z = 8

Data collection top

Bruker SMART APEX area-detector diffractometer	4358 independent reflections
Radiation source: fine-focus sealed tube	2137 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.078
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −5→5
T_min = 0.964, T_max = 0.988	k = −56→56
23870 measured reflections	l = −12→12

Refinement top

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.148	H-atom parameters constrained
S = 0.87	w = 1/[σ²(F_o²) + (0.086P)²] where P = (F_o² + 2F_c²)/3
4358 reflections	(Δ/σ)_max < 0.001
345 parameters	Δρ_max = 0.23 e Å⁻³
0 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₁₄H₁₁FN₂O₂	V = 2481.4 (4) Å³
M_r = 258.25	Z = 8
Monoclinic, P2₁/n	Mo Kα radiation
a = 4.9532 (4) Å	µ = 0.10 mm⁻¹
b = 47.867 (4) Å	T = 298 K
c = 10.7392 (9) Å	0.35 × 0.18 × 0.12 mm
β = 102.953 (2)°

Data collection top

Bruker SMART APEX area-detector diffractometer	4358 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2002)	2137 reflections with I > 2σ(I)
T_min = 0.964, T_max = 0.988	R_int = 0.078
23870 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.054	0 restraints
wR(F²) = 0.148	H-atom parameters constrained
S = 0.87	Δρ_max = 0.23 e Å⁻³
4358 reflections	Δρ_min = −0.22 e Å⁻³
345 parameters

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

	x	y	z	U_iso*/U_eq
F1	−0.6257 (6)	0.26229 (4)	0.7221 (2)	0.1301 (9)
F2	−0.3108 (4)	0.00028 (4)	0.19112 (19)	0.0936 (7)
O1	0.5721 (4)	0.11916 (4)	0.48385 (17)	0.0565 (5)
H1	0.6769	0.1202	0.4348	0.085*
O2	0.2614 (4)	0.10829 (4)	0.80849 (17)	0.0652 (6)
O3	0.9649 (4)	0.13193 (4)	−0.04409 (17)	0.0578 (6)
H3	1.0421	0.1280	−0.1018	0.087*
O4	0.9312 (4)	0.13221 (4)	0.34209 (16)	0.0571 (5)
N1	0.2285 (5)	0.13388 (5)	0.6296 (2)	0.0535 (6)
H1A	0.2695	0.1357	0.5563	0.064*
N2	0.0700 (5)	0.15371 (5)	0.6713 (2)	0.0522 (6)
N3	0.7514 (5)	0.11446 (4)	0.1462 (2)	0.0487 (6)
H3A	0.7474	0.1150	0.0657	0.058*
N4	0.5807 (5)	0.09600 (4)	0.1911 (2)	0.0471 (6)
C1	0.4945 (5)	0.09089 (5)	0.6551 (2)	0.0440 (7)
C2	0.6209 (5)	0.09505 (6)	0.5511 (2)	0.0442 (7)
C3	0.7911 (6)	0.07461 (6)	0.5199 (3)	0.0553 (8)
H3B	0.8789	0.0777	0.4531	0.066*
C4	0.8323 (6)	0.04992 (7)	0.5859 (3)	0.0624 (9)
H4	0.9478	0.0364	0.5637	0.075*
C5	0.7031 (7)	0.04498 (6)	0.6856 (3)	0.0648 (9)
H5	0.7270	0.0281	0.7293	0.078*
C6	0.5394 (6)	0.06549 (6)	0.7184 (3)	0.0562 (8)
H6	0.4547	0.0623	0.7861	0.067*
C7	0.3197 (5)	0.11167 (6)	0.7026 (3)	0.0471 (7)
C8	−0.0106 (6)	0.17390 (6)	0.5964 (3)	0.0580 (8)
H8	0.0377	0.1743	0.5176	0.070*
C9	−0.1765 (6)	0.19658 (6)	0.6295 (3)	0.0550 (8)
C10	−0.2270 (8)	0.22005 (7)	0.5530 (3)	0.0793 (10)
H10	−0.1571	0.2208	0.4796	0.095*
C11	−0.3791 (9)	0.24251 (7)	0.5822 (4)	0.0926 (12)
H11	−0.4116	0.2583	0.5303	0.111*
C12	−0.4793 (8)	0.24048 (7)	0.6911 (4)	0.0851 (11)
C13	−0.4365 (8)	0.21777 (8)	0.7673 (4)	0.0851 (11)
H13	−0.5091	0.2171	0.8399	0.102*
C14	−0.2851 (7)	0.19566 (6)	0.7375 (3)	0.0665 (9)
H14	−0.2556	0.1800	0.7901	0.080*
C15	1.1052 (5)	0.14987 (5)	0.1685 (2)	0.0429 (7)
C16	1.1297 (6)	0.14964 (5)	0.0406 (2)	0.0462 (7)
C17	1.3156 (6)	0.16702 (6)	0.0006 (3)	0.0551 (8)
H17	1.3318	0.1664	−0.0840	0.066*
C18	1.4765 (6)	0.18518 (6)	0.0840 (3)	0.0629 (9)
H18	1.6011	0.1968	0.0561	0.075*
C19	1.4533 (7)	0.18615 (6)	0.2101 (3)	0.0672 (9)
H19	1.5601	0.1986	0.2672	0.081*
C20	1.2722 (6)	0.16866 (6)	0.2495 (3)	0.0575 (8)
H20	1.2598	0.1693	0.3346	0.069*
C21	0.9230 (6)	0.13160 (5)	0.2254 (3)	0.0460 (7)
C22	0.4147 (6)	0.08257 (6)	0.1039 (3)	0.0490 (7)
H22	0.4159	0.0864	0.0191	0.059*
C23	0.2236 (6)	0.06160 (5)	0.1308 (3)	0.0457 (7)
C24	0.0353 (6)	0.04995 (6)	0.0293 (3)	0.0611 (8)
H24	0.0327	0.0560	−0.0533	0.073*
C25	−0.1479 (7)	0.02965 (7)	0.0480 (3)	0.0679 (9)
H25	−0.2759	0.0221	−0.0206	0.082*
C26	−0.1370 (7)	0.02085 (6)	0.1702 (3)	0.0617 (8)
C27	0.0456 (7)	0.03181 (6)	0.2732 (3)	0.0663 (9)
H27	0.0475	0.0256	0.3554	0.080*
C28	0.2269 (7)	0.05228 (6)	0.2532 (3)	0.0593 (8)
H28	0.3525	0.0599	0.3224	0.071*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.156 (2)	0.0998 (16)	0.146 (2)	0.0663 (16)	0.0584 (18)	0.0092 (14)
F2	0.0897 (15)	0.0772 (12)	0.1212 (18)	−0.0317 (11)	0.0388 (13)	−0.0007 (11)
O1	0.0657 (14)	0.0655 (12)	0.0473 (12)	0.0061 (11)	0.0317 (10)	0.0092 (10)
O2	0.0869 (15)	0.0802 (14)	0.0377 (11)	0.0165 (12)	0.0333 (11)	0.0089 (10)
O3	0.0662 (13)	0.0778 (14)	0.0370 (11)	−0.0146 (11)	0.0275 (10)	−0.0108 (10)
O4	0.0658 (13)	0.0781 (14)	0.0319 (11)	−0.0136 (10)	0.0207 (9)	−0.0006 (9)
N1	0.0694 (17)	0.0592 (15)	0.0382 (13)	0.0120 (13)	0.0256 (12)	0.0039 (12)
N2	0.0597 (16)	0.0573 (15)	0.0418 (14)	0.0087 (13)	0.0160 (12)	−0.0019 (12)
N3	0.0590 (15)	0.0543 (14)	0.0371 (13)	−0.0086 (13)	0.0198 (12)	0.0005 (11)
N4	0.0521 (14)	0.0500 (14)	0.0429 (14)	−0.0042 (12)	0.0184 (12)	0.0027 (11)
C1	0.0477 (16)	0.0533 (17)	0.0328 (14)	0.0022 (14)	0.0130 (13)	−0.0003 (13)
C2	0.0453 (17)	0.0534 (17)	0.0342 (15)	−0.0009 (14)	0.0095 (13)	0.0000 (13)
C3	0.0581 (19)	0.071 (2)	0.0408 (17)	0.0088 (17)	0.0202 (14)	−0.0006 (15)
C4	0.066 (2)	0.068 (2)	0.054 (2)	0.0182 (17)	0.0173 (17)	−0.0019 (16)
C5	0.084 (2)	0.063 (2)	0.0497 (19)	0.0135 (18)	0.0218 (17)	0.0106 (15)
C6	0.065 (2)	0.066 (2)	0.0425 (17)	0.0064 (17)	0.0215 (15)	0.0059 (15)
C7	0.0489 (17)	0.0596 (18)	0.0355 (16)	−0.0032 (15)	0.0154 (14)	−0.0002 (14)
C8	0.074 (2)	0.063 (2)	0.0416 (17)	0.0090 (18)	0.0217 (16)	0.0000 (15)
C9	0.064 (2)	0.0549 (19)	0.0457 (18)	0.0072 (16)	0.0117 (15)	0.0005 (15)
C10	0.108 (3)	0.074 (2)	0.058 (2)	0.020 (2)	0.024 (2)	0.0079 (18)
C11	0.127 (3)	0.065 (2)	0.085 (3)	0.027 (2)	0.023 (3)	0.020 (2)
C12	0.101 (3)	0.065 (2)	0.093 (3)	0.031 (2)	0.031 (2)	0.002 (2)
C13	0.106 (3)	0.084 (3)	0.078 (3)	0.030 (2)	0.048 (2)	0.009 (2)
C14	0.077 (2)	0.067 (2)	0.062 (2)	0.0204 (18)	0.0311 (18)	0.0084 (17)
C15	0.0482 (16)	0.0491 (16)	0.0353 (15)	−0.0021 (14)	0.0176 (13)	0.0006 (13)
C16	0.0476 (17)	0.0529 (17)	0.0394 (16)	−0.0004 (14)	0.0128 (14)	−0.0021 (14)
C17	0.063 (2)	0.0665 (19)	0.0403 (17)	−0.0057 (17)	0.0219 (15)	0.0069 (15)
C18	0.066 (2)	0.065 (2)	0.063 (2)	−0.0183 (17)	0.0244 (18)	0.0059 (17)
C19	0.081 (2)	0.075 (2)	0.0477 (19)	−0.0281 (19)	0.0184 (17)	−0.0067 (16)
C20	0.073 (2)	0.0629 (19)	0.0418 (17)	−0.0141 (17)	0.0241 (15)	−0.0048 (15)
C21	0.0498 (17)	0.0515 (17)	0.0400 (17)	0.0028 (14)	0.0170 (14)	−0.0004 (14)
C22	0.0545 (18)	0.0556 (18)	0.0396 (16)	−0.0014 (15)	0.0162 (14)	0.0004 (14)
C23	0.0512 (18)	0.0454 (16)	0.0426 (16)	−0.0017 (14)	0.0148 (14)	−0.0035 (13)
C24	0.061 (2)	0.072 (2)	0.0492 (19)	−0.0114 (18)	0.0112 (16)	−0.0049 (16)
C25	0.065 (2)	0.075 (2)	0.060 (2)	−0.0102 (18)	0.0054 (17)	−0.0065 (17)
C26	0.058 (2)	0.0504 (19)	0.081 (3)	−0.0139 (16)	0.0248 (18)	−0.0088 (17)
C27	0.083 (2)	0.061 (2)	0.064 (2)	−0.0103 (19)	0.035 (2)	0.0035 (17)
C28	0.071 (2)	0.0609 (19)	0.0462 (18)	−0.0104 (17)	0.0137 (15)	−0.0011 (15)

Geometric parameters (Å, º) top

F1—C12	1.355 (4)	C10—C11	1.389 (4)
F2—C26	1.359 (3)	C10—H10	0.9300
O1—C2	1.354 (3)	C11—C12	1.372 (5)
O1—H1	0.8200	C11—H11	0.9300
O2—C7	1.245 (3)	C12—C13	1.348 (4)
O3—C16	1.371 (3)	C13—C14	1.376 (4)
O3—H3	0.8200	C13—H13	0.9300
O4—C21	1.245 (3)	C14—H14	0.9300
N1—C7	1.338 (3)	C15—C20	1.388 (4)
N1—N2	1.370 (3)	C15—C16	1.406 (3)
N1—H1A	0.8600	C15—C21	1.483 (3)
N2—C8	1.263 (3)	C16—C17	1.379 (4)
N3—C21	1.340 (3)	C17—C18	1.369 (4)
N3—N4	1.383 (3)	C17—H17	0.9300
N3—H3A	0.8600	C18—C19	1.386 (4)
N4—C22	1.273 (3)	C18—H18	0.9300
C1—C6	1.386 (3)	C19—C20	1.362 (4)
C1—C2	1.411 (3)	C19—H19	0.9300
C1—C7	1.483 (4)	C20—H20	0.9300
C2—C3	1.381 (3)	C22—C23	1.452 (4)
C3—C4	1.370 (4)	C22—H22	0.9300
C3—H3B	0.9300	C23—C24	1.384 (4)
C4—C5	1.385 (4)	C23—C28	1.385 (4)
C4—H4	0.9300	C24—C25	1.375 (4)
C5—C6	1.369 (4)	C24—H24	0.9300
C5—H5	0.9300	C25—C26	1.367 (4)
C6—H6	0.9300	C25—H25	0.9300
C8—C9	1.453 (4)	C26—C27	1.367 (4)
C8—H8	0.9300	C27—C28	1.378 (4)
C9—C10	1.381 (4)	C27—H27	0.9300
C9—C14	1.384 (4)	C28—H28	0.9300

C2—O1—H1	109.5	C12—C13—H13	120.0
C16—O3—H3	109.5	C14—C13—H13	120.0
C7—N1—N2	120.1 (2)	C13—C14—C9	120.3 (3)
C7—N1—H1A	119.9	C13—C14—H14	119.8
N2—N1—H1A	119.9	C9—C14—H14	119.8
C8—N2—N1	116.4 (2)	C20—C15—C16	116.6 (2)
C21—N3—N4	121.4 (2)	C20—C15—C21	117.1 (2)
C21—N3—H3A	119.3	C16—C15—C21	126.3 (2)
N4—N3—H3A	119.3	O3—C16—C17	120.4 (2)
C22—N4—N3	114.3 (2)	O3—C16—C15	119.0 (2)
C6—C1—C2	117.5 (2)	C17—C16—C15	120.7 (3)
C6—C1—C7	117.5 (2)	C18—C17—C16	120.7 (3)
C2—C1—C7	125.1 (2)	C18—C17—H17	119.6
O1—C2—C3	121.3 (2)	C16—C17—H17	119.6
O1—C2—C1	119.0 (2)	C17—C18—C19	119.8 (3)
C3—C2—C1	119.7 (2)	C17—C18—H18	120.1
C4—C3—C2	120.9 (3)	C19—C18—H18	120.1
C4—C3—H3B	119.5	C20—C19—C18	119.2 (3)
C2—C3—H3B	119.5	C20—C19—H19	120.4
C3—C4—C5	120.4 (3)	C18—C19—H19	120.4
C3—C4—H4	119.8	C19—C20—C15	123.0 (3)
C5—C4—H4	119.8	C19—C20—H20	118.5
C6—C5—C4	118.6 (3)	C15—C20—H20	118.5
C6—C5—H5	120.7	O4—C21—N3	121.8 (2)
C4—C5—H5	120.7	O4—C21—C15	121.0 (2)
C5—C6—C1	122.8 (3)	N3—C21—C15	117.2 (2)
C5—C6—H6	118.6	N4—C22—C23	123.0 (3)
C1—C6—H6	118.6	N4—C22—H22	118.5
O2—C7—N1	121.4 (2)	C23—C22—H22	118.5
O2—C7—C1	120.0 (3)	C24—C23—C28	118.7 (3)
N1—C7—C1	118.6 (2)	C24—C23—C22	118.4 (3)
N2—C8—C9	122.1 (3)	C28—C23—C22	122.8 (3)
N2—C8—H8	119.0	C25—C24—C23	121.3 (3)
C9—C8—H8	119.0	C25—C24—H24	119.3
C10—C9—C14	118.2 (3)	C23—C24—H24	119.3
C10—C9—C8	119.9 (3)	C26—C25—C24	118.2 (3)
C14—C9—C8	121.9 (3)	C26—C25—H25	120.9
C9—C10—C11	122.0 (3)	C24—C25—H25	120.9
C9—C10—H10	119.0	F2—C26—C27	118.2 (3)
C11—C10—H10	119.0	F2—C26—C25	119.4 (3)
C12—C11—C10	117.1 (3)	C27—C26—C25	122.3 (3)
C12—C11—H11	121.4	C26—C27—C28	118.8 (3)
C10—C11—H11	121.4	C26—C27—H27	120.6
C13—C12—F1	119.5 (4)	C28—C27—H27	120.6
C13—C12—C11	122.4 (3)	C27—C28—C23	120.5 (3)
F1—C12—C11	118.1 (3)	C27—C28—H28	119.7
C12—C13—C14	119.9 (3)	C23—C28—H28	119.7

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O4	0.82	1.86	2.662 (2)	165
O3—H3···O2ⁱ	0.82	1.86	2.643 (2)	159
N1—H1A···O1	0.86	2.00	2.653 (3)	132
N1—H1A···O4ⁱⁱ	0.86	2.53	3.109 (3)	126
N3—H3A···O3	0.86	1.94	2.638 (3)	137

Symmetry codes: (i) x+1, y, z−1; (ii) x−1, y, z.

Experimental details

Crystal data
Chemical formula	C₁₄H₁₁FN₂O₂
M_r	258.25
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	298
a, b, c (Å)	4.9532 (4), 47.867 (4), 10.7392 (9)
β (°)	102.953 (2)
V (Å³)	2481.4 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.35 × 0.18 × 0.12

Data collection
Diffractometer	Bruker SMART APEX area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2002)
T_min, T_max	0.964, 0.988
No. of measured, independent and observed [I > 2σ(I)] reflections	23870, 4358, 2137
R_int	0.078
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.054, 0.148, 0.87
No. of reflections	4358
No. of parameters	345
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.22

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII(Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1993), SHELXL97.

Selected bond lengths (Å) top

N1—C7	1.338 (3)	N3—C21	1.340 (3)
N1—N2	1.370 (3)	N3—N4	1.383 (3)
N2—C8	1.263 (3)	N4—C22	1.273 (3)