2,2-Dimethyl-N,N′-bis­(4-nitro­benzyl­idene)propane-1,3-diamine

Fun, H.-K.; Kargar, H.; Kia, R.

doi:10.1107/S1600536808037033

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 12| December 2008| Page o2335

doi:10.1107/S1600536808037033

Open

access

2,2-Dimethyl-N,N′-bis(4-nitrobenzylidene)propane-1,3-diamine

Hoong-Kun Fun,^a ^* Hadi Kargar ^b ‡ and Reza Kia ^a

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bDepartment of Chemistry, School of Science, Payame Noor University (PNU), Ardakan, Yazd, Iran
^*Correspondence e-mail: hkfun@usm.my

(Received 1 November 2008; accepted 10 November 2008; online 13 November 2008)

In the title compound, C₁₉H₂₀N₄O₄, a potential bidentate Schiff base ligand, each imino (C=N) functional group is coplanar with the adjacent benzene ring. The two benzene rings form a dihedral angle of 10.52 (6)°. Intermolecular C—H⋯O contacts link neighbouring molecules into supramolecular array with an R²₂(32) ring motif and a C—H⋯π contact is also present.

Related literature

For details of hydrogen-bond motifs, see: Bernstein et al. (1995 ). For related structures, see: Li et al. (2005 ); Bomfim et al. (2005 ); Glidewell et al. (2005 , 2006 ); Sun et al. (2004 ); Fun et al. (2008a ,b ).

Experimental

Crystal data

C₁₉H₂₀N₄O₄
M_r = 368.39
Monoclinic, P 2₁ /c
a = 7.8219 (1) Å
b = 19.9716 (4) Å
c = 12.0125 (3) Å
β = 92.831 (1)°
V = 1874.25 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 (1) K
0.45 × 0.19 × 0.08 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.959, T_max = 0.993
21845 measured reflections
6784 independent reflections
4307 reflections with I > 2σ(I)
R_int = 0.048

Refinement

R[F² > 2σ(F²)] = 0.061
wR(F²) = 0.152
S = 1.04
6784 reflections
244 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O4ⁱ	0.93	2.52	3.4330 (18)	168
C17—H17A⋯O2ⁱⁱ	0.93	2.48	3.4063 (18)	171
C19—H19A⋯Cg1ⁱⁱⁱ	0.96	2.86	3.8058 (16)	171
Symmetry codes: (i) -x+1, -y+1, -z+2; (ii) -x+2, -y+1, -z+1; (iii) $[x, -y-{\script{1\over 2}}, z-{\script{3\over 2}}]$ . Cg1 is the centroid of the C12–C17 benzene ring.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); 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 and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808037033/tk2324sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808037033/tk2324Isup2.hkl

checkCIF report

Comment top

Schiff bases are one of most prevalent mixed-donor ligands in the field of coordination chemistry. They play an important role in the development of coordination chemistry related to catalysis and enzymatic reactions, magnetism, and supramolecular architectures. Structures of Schiff bases derived from substituted benzaldehydes and closely related to the title compound, (I), have been reported previously (Li et al., 2005; Bomfim et al., 2005; Glidewell et al., 2005, 2006; Sun et al., 2004; Fun et al., 2008a,b).

Each imino (C ═N) functional group in (I), Fig. 1, is co-planar with the adjacent benzene ring. Intramolecular C—H···O contacts form five-membered rings, producing S(5) ring motifs (Bernstein et al., 1995). The two benzene rings form a dihedral angle of 10.52 (6)°. Intermolecular C—H···O contacts link neighbouring molecules into supramolecular array with R²₂(32) ring motif, Fig. 2 and Table 1. The crystal structure is further stabilized by weak C—H···π interactions, ( Table 1.

Related literature top

For details of hydrogen-bond motifs, see: Bernstein et al. (1995). For related structures, see: Li et al. (2005); Bomfim et al. (2005); Glidewell et al. (2005, 2006); Sun et al. (2004); Fun et al. (2008a,b). Cg1 is the centroid of the C12–C17 benzene ring.

Experimental top

The synthetic method has been described earlier (Fun et al., 2008). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution of (I) held at room temperature.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of (I) with atom labels and 50% displacement ellipsoids for non-H atoms.
	Fig. 2. The crystal packing of (I), viewed down the c-axis showing the linking of neighbouring molecules via R²₂(32) ring motifs. Intermolecular hydrogen bonds are shown as dashed lines.

2,2-Dimethyl-N,N'-bis(4-nitrobenzylidene)propane-1,3-diamine top

Crystal data top

C₁₉H₂₀N₄O₄	F(000) = 776
M_r = 368.39	D_x = 1.306 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3284 reflections
a = 7.8219 (1) Å	θ = 2.7–28.9°
b = 19.9716 (4) Å	µ = 0.09 mm⁻¹
c = 12.0125 (3) Å	T = 100 K
β = 92.831 (1)°	Block, colourless
V = 1874.25 (6) Å³	0.45 × 0.19 × 0.08 mm
Z = 4

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	6784 independent reflections
Radiation source: fine-focus sealed tube	4307 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.048
ϕ and ω scans	θ_max = 32.6°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −11→11
T_min = 0.959, T_max = 0.993	k = −30→24
21845 measured reflections	l = −16→18

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)] = 0.061	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.152	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.063P)² + 0.2454P] where P = (F_o² + 2F_c²)/3
6784 reflections	(Δ/σ)_max < 0.001
244 parameters	Δρ_max = 0.36 e Å⁻³
0 restraints	Δρ_min = −0.23 e Å⁻³

Crystal data top

C₁₉H₂₀N₄O₄	V = 1874.25 (6) Å³
M_r = 368.39	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 7.8219 (1) Å	µ = 0.09 mm⁻¹
b = 19.9716 (4) Å	T = 100 K
c = 12.0125 (3) Å	0.45 × 0.19 × 0.08 mm
β = 92.831 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	6784 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	4307 reflections with I > 2σ(I)
T_min = 0.959, T_max = 0.993	R_int = 0.048
21845 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.061	0 restraints
wR(F²) = 0.152	H-atom parameters constrained
S = 1.04	Δρ_max = 0.36 e Å⁻³
6784 reflections	Δρ_min = −0.23 e Å⁻³
244 parameters

Special details top

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

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
O1	1.36590 (14)	0.55914 (6)	0.45685 (10)	0.0335 (3)
O2	1.36634 (15)	0.48567 (6)	0.32431 (10)	0.0376 (3)
O3	0.04816 (14)	0.42804 (6)	1.17606 (9)	0.0317 (3)
O4	0.13096 (14)	0.52456 (5)	1.11560 (10)	0.0313 (3)
N1	0.91963 (15)	0.26572 (6)	0.65265 (11)	0.0229 (3)
N2	0.44695 (14)	0.27677 (6)	0.73309 (11)	0.0232 (3)
N3	1.32746 (15)	0.50399 (7)	0.41710 (12)	0.0263 (3)
N4	0.12292 (14)	0.46308 (6)	1.10932 (10)	0.0240 (3)
C1	1.07594 (17)	0.43692 (7)	0.64720 (12)	0.0214 (3)
H1A	1.0348	0.4512	0.7146	0.026*
C2	1.17251 (17)	0.48038 (7)	0.58500 (12)	0.0222 (3)
H2A	1.1983	0.5234	0.6103	0.027*
C3	1.22894 (16)	0.45767 (7)	0.48441 (12)	0.0212 (3)
C4	1.19437 (18)	0.39416 (8)	0.44352 (13)	0.0254 (3)
H4A	1.2337	0.3806	0.3753	0.031*
C5	1.09965 (17)	0.35135 (7)	0.50692 (13)	0.0245 (3)
H5A	1.0751	0.3083	0.4813	0.029*
C6	1.04054 (16)	0.37232 (7)	0.60928 (12)	0.0195 (3)
C7	0.94133 (16)	0.32672 (7)	0.67822 (12)	0.0205 (3)
H7A	0.8936	0.3432	0.7421	0.025*
C8	0.81845 (17)	0.22410 (7)	0.72454 (12)	0.0220 (3)
H8A	0.7833	0.2506	0.7871	0.026*
H8B	0.8885	0.1874	0.7537	0.026*
C9	0.65824 (17)	0.19558 (7)	0.66089 (12)	0.0211 (3)
C10	0.52727 (18)	0.25158 (7)	0.63434 (13)	0.0228 (3)
H10A	0.5843	0.2883	0.5986	0.027*
H10B	0.4391	0.2346	0.5821	0.027*
C11	0.44070 (16)	0.33980 (7)	0.74535 (12)	0.0211 (3)
H11A	0.4901	0.3673	0.6933	0.025*
C12	0.35718 (16)	0.37059 (7)	0.83998 (12)	0.0192 (3)
C13	0.25521 (16)	0.33267 (7)	0.90909 (12)	0.0214 (3)
H13A	0.2384	0.2873	0.8946	0.026*
C14	0.17916 (17)	0.36202 (7)	0.99872 (12)	0.0222 (3)
H14A	0.1125	0.3369	1.0453	0.027*
C15	0.20531 (16)	0.43004 (7)	1.01696 (12)	0.0203 (3)
C16	0.30321 (16)	0.46938 (7)	0.94913 (12)	0.0210 (3)
H16A	0.3173	0.5149	0.9627	0.025*
C17	0.37936 (17)	0.43876 (7)	0.86057 (12)	0.0215 (3)
H17A	0.4461	0.4641	0.8143	0.026*
C18	0.58134 (19)	0.14167 (8)	0.73376 (14)	0.0289 (3)
H18A	0.4811	0.1232	0.6959	0.043*
H18B	0.5507	0.1611	0.8031	0.043*
H18C	0.6639	0.1068	0.7481	0.043*
C19	0.70671 (19)	0.16493 (7)	0.54990 (13)	0.0259 (3)
H19A	0.6059	0.1477	0.5111	0.039*
H19B	0.7870	0.1292	0.5638	0.039*
H19C	0.7577	0.1987	0.5052	0.039*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0318 (6)	0.0268 (6)	0.0423 (7)	−0.0069 (5)	0.0043 (5)	0.0051 (5)
O2	0.0377 (6)	0.0447 (7)	0.0314 (7)	−0.0070 (5)	0.0128 (5)	0.0041 (5)
O3	0.0332 (6)	0.0354 (6)	0.0276 (6)	−0.0072 (5)	0.0108 (5)	−0.0019 (5)
O4	0.0381 (6)	0.0230 (6)	0.0334 (7)	0.0044 (4)	0.0082 (5)	−0.0026 (5)
N1	0.0213 (5)	0.0232 (6)	0.0244 (7)	−0.0026 (4)	0.0020 (5)	−0.0003 (5)
N2	0.0211 (5)	0.0225 (6)	0.0261 (7)	0.0004 (4)	0.0023 (5)	−0.0012 (5)
N3	0.0185 (5)	0.0297 (7)	0.0308 (7)	−0.0009 (5)	0.0019 (5)	0.0075 (6)
N4	0.0202 (5)	0.0280 (7)	0.0238 (7)	0.0009 (5)	0.0024 (5)	−0.0016 (5)
C1	0.0197 (6)	0.0234 (7)	0.0211 (7)	0.0017 (5)	0.0010 (5)	−0.0015 (6)
C2	0.0197 (6)	0.0212 (7)	0.0255 (8)	−0.0003 (5)	−0.0016 (5)	−0.0005 (6)
C3	0.0162 (6)	0.0235 (7)	0.0240 (7)	0.0008 (5)	0.0021 (5)	0.0055 (6)
C4	0.0255 (7)	0.0286 (8)	0.0229 (8)	−0.0007 (6)	0.0076 (6)	−0.0018 (6)
C5	0.0254 (7)	0.0228 (7)	0.0257 (8)	−0.0011 (5)	0.0051 (6)	−0.0037 (6)
C6	0.0173 (6)	0.0204 (6)	0.0207 (7)	0.0001 (5)	0.0011 (5)	0.0007 (5)
C7	0.0187 (6)	0.0234 (7)	0.0196 (7)	−0.0003 (5)	0.0018 (5)	−0.0004 (6)
C8	0.0239 (6)	0.0208 (7)	0.0215 (7)	−0.0013 (5)	0.0020 (5)	0.0012 (6)
C9	0.0218 (6)	0.0177 (6)	0.0238 (7)	−0.0015 (5)	0.0013 (5)	−0.0003 (6)
C10	0.0241 (6)	0.0216 (7)	0.0227 (8)	0.0002 (5)	0.0002 (5)	−0.0019 (6)
C11	0.0195 (6)	0.0219 (7)	0.0220 (7)	−0.0001 (5)	0.0018 (5)	0.0010 (6)
C12	0.0170 (6)	0.0200 (6)	0.0204 (7)	0.0021 (5)	−0.0001 (5)	0.0015 (5)
C13	0.0195 (6)	0.0179 (6)	0.0268 (8)	−0.0007 (5)	0.0015 (5)	0.0002 (6)
C14	0.0192 (6)	0.0229 (7)	0.0248 (8)	0.0000 (5)	0.0036 (5)	0.0046 (6)
C15	0.0180 (6)	0.0228 (7)	0.0201 (7)	0.0024 (5)	0.0010 (5)	−0.0002 (5)
C16	0.0207 (6)	0.0180 (6)	0.0242 (7)	0.0002 (5)	0.0007 (5)	0.0003 (6)
C17	0.0207 (6)	0.0211 (7)	0.0229 (7)	−0.0005 (5)	0.0027 (5)	0.0031 (6)
C18	0.0282 (7)	0.0228 (7)	0.0357 (9)	−0.0041 (6)	0.0025 (6)	0.0048 (7)
C19	0.0275 (7)	0.0212 (7)	0.0289 (8)	0.0011 (5)	−0.0008 (6)	−0.0045 (6)

Geometric parameters (Å, º) top

O1—N3	1.2319 (17)	C8—H8B	0.9700
O2—N3	1.2256 (17)	C9—C18	1.530 (2)
O3—N4	1.2330 (15)	C9—C19	1.532 (2)
O4—N4	1.2316 (16)	C9—C10	1.539 (2)
N1—C7	1.2657 (18)	C10—H10A	0.9700
N1—C8	1.4597 (17)	C10—H10B	0.9700
N2—C11	1.2687 (18)	C11—C12	1.4732 (19)
N2—C10	1.4591 (18)	C11—H11A	0.9300
N3—C3	1.4714 (18)	C12—C17	1.3931 (19)
N4—C15	1.4671 (18)	C12—C13	1.4014 (18)
C1—C6	1.3914 (19)	C13—C14	1.3857 (19)
C1—C2	1.3921 (19)	C13—H13A	0.9300
C1—H1A	0.9300	C14—C15	1.389 (2)
C2—C3	1.383 (2)	C14—H14A	0.9300
C2—H2A	0.9300	C15—C16	1.3890 (18)
C3—C4	1.382 (2)	C16—C17	1.3868 (19)
C4—C5	1.3840 (19)	C16—H16A	0.9300
C4—H4A	0.9300	C17—H17A	0.9300
C5—C6	1.3990 (19)	C18—H18A	0.9600
C5—H5A	0.9300	C18—H18B	0.9600
C6—C7	1.4768 (18)	C18—H18C	0.9600
C7—H7A	0.9300	C19—H19A	0.9600
C8—C9	1.544 (2)	C19—H19B	0.9600
C8—H8A	0.9700	C19—H19C	0.9600

C7—N1—C8	118.34 (12)	C10—C9—C8	110.49 (11)
C11—N2—C10	117.20 (12)	N2—C10—C9	113.01 (12)
O2—N3—O1	123.55 (13)	N2—C10—H10A	109.0
O2—N3—C3	118.19 (13)	C9—C10—H10A	109.0
O1—N3—C3	118.26 (13)	N2—C10—H10B	109.0
O4—N4—O3	123.39 (12)	C9—C10—H10B	109.0
O4—N4—C15	118.14 (12)	H10A—C10—H10B	107.8
O3—N4—C15	118.47 (12)	N2—C11—C12	121.65 (13)
C6—C1—C2	120.46 (13)	N2—C11—H11A	119.2
C6—C1—H1A	119.8	C12—C11—H11A	119.2
C2—C1—H1A	119.8	C17—C12—C13	119.50 (12)
C3—C2—C1	118.00 (13)	C17—C12—C11	119.26 (12)
C3—C2—H2A	121.0	C13—C12—C11	121.24 (12)
C1—C2—H2A	121.0	C14—C13—C12	120.69 (13)
C4—C3—C2	123.10 (13)	C14—C13—H13A	119.7
C4—C3—N3	118.70 (13)	C12—C13—H13A	119.7
C2—C3—N3	118.18 (13)	C13—C14—C15	118.07 (12)
C3—C4—C5	118.16 (13)	C13—C14—H14A	121.0
C3—C4—H4A	120.9	C15—C14—H14A	121.0
C5—C4—H4A	120.9	C16—C15—C14	122.80 (13)
C4—C5—C6	120.52 (14)	C16—C15—N4	117.69 (12)
C4—C5—H5A	119.7	C14—C15—N4	119.48 (12)
C6—C5—H5A	119.7	C17—C16—C15	118.07 (13)
C1—C6—C5	119.75 (13)	C17—C16—H16A	121.0
C1—C6—C7	119.33 (12)	C15—C16—H16A	121.0
C5—C6—C7	120.92 (13)	C16—C17—C12	120.85 (12)
N1—C7—C6	121.69 (13)	C16—C17—H17A	119.6
N1—C7—H7A	119.2	C12—C17—H17A	119.6
C6—C7—H7A	119.2	C9—C18—H18A	109.5
N1—C8—C9	111.56 (12)	C9—C18—H18B	109.5
N1—C8—H8A	109.3	H18A—C18—H18B	109.5
C9—C8—H8A	109.3	C9—C18—H18C	109.5
N1—C8—H8B	109.3	H18A—C18—H18C	109.5
C9—C8—H8B	109.3	H18B—C18—H18C	109.5
H8A—C8—H8B	108.0	C9—C19—H19A	109.5
C18—C9—C19	109.76 (12)	C9—C19—H19B	109.5
C18—C9—C10	110.70 (11)	H19A—C19—H19B	109.5
C19—C9—C10	107.51 (12)	C9—C19—H19C	109.5
C18—C9—C8	107.98 (12)	H19A—C19—H19C	109.5
C19—C9—C8	110.41 (11)	H19B—C19—H19C	109.5

C6—C1—C2—C3	1.0 (2)	C11—N2—C10—C9	131.95 (13)
C1—C2—C3—C4	−0.2 (2)	C18—C9—C10—N2	49.59 (16)
C1—C2—C3—N3	178.53 (12)	C19—C9—C10—N2	169.47 (11)
O2—N3—C3—C4	4.2 (2)	C8—C9—C10—N2	−69.98 (14)
O1—N3—C3—C4	−176.02 (13)	C10—N2—C11—C12	177.85 (12)
O2—N3—C3—C2	−174.58 (13)	N2—C11—C12—C17	168.88 (14)
O1—N3—C3—C2	5.17 (19)	N2—C11—C12—C13	−11.5 (2)
C2—C3—C4—C5	−0.4 (2)	C17—C12—C13—C14	−1.2 (2)
N3—C3—C4—C5	−179.16 (13)	C11—C12—C13—C14	179.15 (13)
C3—C4—C5—C6	0.2 (2)	C12—C13—C14—C15	0.8 (2)
C2—C1—C6—C5	−1.2 (2)	C13—C14—C15—C16	0.3 (2)
C2—C1—C6—C7	178.54 (12)	C13—C14—C15—N4	178.38 (13)
C4—C5—C6—C1	0.6 (2)	O4—N4—C15—C16	6.84 (19)
C4—C5—C6—C7	−179.19 (13)	O3—N4—C15—C16	−173.73 (12)
C8—N1—C7—C6	−179.39 (12)	O4—N4—C15—C14	−171.35 (13)
C1—C6—C7—N1	−173.22 (14)	O3—N4—C15—C14	8.09 (19)
C5—C6—C7—N1	6.5 (2)	C14—C15—C16—C17	−0.9 (2)
C7—N1—C8—C9	118.97 (14)	N4—C15—C16—C17	−179.01 (12)
N1—C8—C9—C18	168.26 (11)	C15—C16—C17—C12	0.4 (2)
N1—C8—C9—C19	48.27 (15)	C13—C12—C17—C16	0.6 (2)
N1—C8—C9—C10	−70.53 (14)	C11—C12—C17—C16	−179.76 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O4ⁱ	0.93	2.52	3.4330 (18)	168
C17—H17A···O2ⁱⁱ	0.93	2.48	3.4063 (18)	171
C19—H19A···Cg1ⁱⁱⁱ	0.96	2.86	3.8058 (16)	171

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+2, −y+1, −z+1; (iii) x, −y−1/2, z−3/2.

Experimental details

Crystal data
Chemical formula	C₁₉H₂₀N₄O₄
M_r	368.39
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	7.8219 (1), 19.9716 (4), 12.0125 (3)
β (°)	92.831 (1)
V (Å³)	1874.25 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.45 × 0.19 × 0.08

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.959, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	21845, 6784, 4307
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.758

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.061, 0.152, 1.04
No. of reflections	6784
No. of parameters	244
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.23

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O4ⁱ	0.93	2.52	3.4330 (18)	168
C17—H17A···O2ⁱⁱ	0.93	2.48	3.4063 (18)	171
C19—H19A···Cg1ⁱⁱⁱ	0.96	2.86	3.8058 (16)	171

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+2, −y+1, −z+1; (iii) x, −y−1/2, z−3/2.

Footnotes

‡Additional correspondence author, e-mail: hkargar@pnu.ac.ir.

Acknowledgements

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for a post-doctoral research fellowship. HK thanks PNU for financial support.

References

Bernstein, J., Davis, R. E., Shimoni, L. & Chamg, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bomfim, J. A. S., Wardell, J. L., Low, J. N., Skakle, J. M. S. & Glidewell, C. (2005). Acta Cryst. C61, o53–o56. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Fun, H.-K., Kargar, H. & Kia, R. (2008a). Acta Cryst. E64, o1308. Web of Science CSD CrossRef IUCr Journals Google Scholar
Fun, H.-K., Kargar, H. & Kia, R. (2008b). Acta Cryst. E64, o2273. Web of Science CSD CrossRef IUCr Journals Google Scholar
Glidewell, C., Low, J. N., Skakle, J. M. S. & Wardell, J. L. (2005). Acta Cryst. E61, o3551–o3553. Web of Science CSD CrossRef IUCr Journals Google Scholar
Glidewell, C., Low, J. N., Skakle, J. M. S. & Wardell, J. L. (2006). Acta Cryst. C62, o1–o4. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Li, Y.-G., Zhu, H.-L., Chen, X.-Z. & Song, Y. (2005). Acta Cryst. E61, o4156–o4157. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sun, Y.-X., You, Z.-L. & Zhu, H.-L. (2004). Acta Cryst. E60, o1707–o1708. Web of Science CSD CrossRef IUCr Journals Google Scholar