1,5-Bis(2-methyl­phen­yl)-3-nitro­formazan

Eschwege, K.G. von; Hosten, E.C.; Muller, A.

doi:10.1107/S1600536812001171

organic compounds

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ISSN: 2056-9890

Volume 68| Part 2| February 2012| Page o425

doi:10.1107/S1600536812001171

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1,5-Bis(2-methylphenyl)-3-nitroformazan

Karel G. von Eschwege,^a ^* Eric C. Hosten ^b and Alfred Muller ^c

^aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa, ^bDepartment of Chemistry, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031, South Africa, and ^cResearch Center for Synthesis and Catalysis, Department of Chemistry, University of Johannesburg (APK Campus), PO Box 524, Auckland Park, Johannesburg 2006, South Africa
^*Correspondence e-mail: veschwkg@ufs.ac.za

(Received 12 December 2011; accepted 10 January 2012; online 18 January 2012)

In the title compound, C₁₅H₁₅N₅O₂, the nitro O atoms are disordered over two sets of sites with an occupancy ratio of 0.75 (4):0.25 (4). Amine–imine tautomerism is observed in the formazan group. This was evident from the similar C—N bond distances in the formazan [1.319 (2) and 1.332 (3) Å], as well as the distribution of the imine proton in the Fourier difference map which refined to a 0.53 (3):0.47 (3) ratio. C—H⋯O and π–π interactions [centroid–centroid distances = 3.4813 (1) and 3.3976 (1) Å] are observed in the crystal packing.

Related literature

For related structures of nitroformazan derivatives, see: Gilroy et al. (2008 ); Mito et al. (1997 ) and for a related dithizone structure, see: Laing (1977 ). For the synthesis and chemistry of nitroformazans, see: Pelkis et al. (1957 ); Irving (1977 ). For DFT and electrochemistry studies of dithizones, see: Von Eschwege & Swarts (2010 ); Von Eschwege et al. (2011 ).

Experimental

Crystal data

C₁₅H₁₅N₅O₂
M_r = 297.32
Orthorhombic, P b c a
a = 14.6525 (3) Å
b = 10.2523 (3) Å
c = 19.2425 (4) Å
V = 2890.64 (12) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 200 K
0.43 × 0.19 × 0.19 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ) T_min = 0.960, T_max = 0.982
24031 measured reflections
3619 independent reflections
2487 reflections with I > 2σ(I)
R_int = 0.028

Refinement

R[F² > 2σ(F²)] = 0.060
wR(F²) = 0.180
S = 1.05
3619 reflections
221 parameters
48 restraints
H-atom parameters constrained
Δρ_max = 0.51 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O1Aⁱ	0.95	2.42	3.239 (9)	145
Symmetry code: (i) $[x-{\script{1\over 2}}, -y-{\script{1\over 2}}, -z]$ .

Data collection: APEX2 (Bruker, 2011 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT and XPREP (Bruker, 2008); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812001171/kp2378sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812001171/kp2378Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812001171/kp2378Isup3.cml

checkCIF report

Comment top

During synthesis of the versatile trace metal analysis dithizone reagent, aniline is first diazotized and then treated with nitromethane to form the bright orange-red nitroformazan product (Pelkis et al., 1957). Ammonia and hydrogen sulfide gas is used to substitute the nitro group with sulfur towards the formation of dithizone, the chemistry of which is extensively described by Irving, 1977. Single crystal X-ray structures of nitroformazan derivatives were determined by Gilroy et al., 2008; Mito et al.,1997, and the dithizone structure by Laing, 1977, while we performed extensive DFT (Von Eschwege et al., 2011) and electrochemistry studies (Von Eschwege & Swarts, 2010) on the free ligand. We recently embarked on a study during which we synthesized a series of electronically altered dithizones for the purpose of investigating its altered redox and structural properties. During this process orange 1,5-bis(2-methylphenyl)-3-nitroformazan crystals suitable for X-ray structure analysis were grown from an acetone solution overlaid with n-hexane.

The title compound (Fig. 1) crystallises with the 2-methylphenyl moieties in different orientations, i.e. C1—C7 and C9—C15 have dihedral angles of of 12.64 (9)° and 3.27 (9)° respectively with the N—N═ C—N═N backbone. The preferred orientations are probably due to the observed C—H···O interactions as well as the π-stacking of 2-methylphenyl aromatic rings (Tables 1 and 2, Fig. 2) with neighbouring N—N═C—N═N conjugates creating a zigzag packing motif (Fig. 3).

The structure showed large thermal vibrations at the NO₂ moiety and was treated for disorder. From the Fourier difference map the imine hydrogen was also detected as being disordered over two nitrogen atoms. Details of these can be found in the refinement section.

Related literature top

For related structures of nitroformazan derivatives, see: Gilroy et al. (2008); Mito et al. (1997) and for a related dithizone structure, see: Laing (1977). For the synthesis and chemistry of nitroformazans, see: Pelkis et al. (1957); Irving (1977). For DFT and electrochemistry studies of dithizones, see: Von Eschwege & Swarts (2010); Von Eschwege et al. (2011).

Experimental top

Solvents (AR) purchased from Merck and reagents from Sigma-Aldrich were used without further purification. The ortho-methyl derivative of nitroformazan was prepared according to the procedure reported by Pelkis et al., 1957.

Computing details top

Data collection: APEX2 (Bruker, 2011); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT and XPREP (Bruker, 2008); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. View of the title compound with labelling and displacement ellipsoids drawn at a 50% probability level. Hydrogen atoms and minor components of disorders not shown for clarity.
	Fig. 2. Partial packing diagram of title compound indicating the π···π interactions.
	Fig. 3. Packing diagram of the title compound viewed along the a axis illustrating the zigzag packing motif.

2-[(2-methylphenyl)amino]-3-[(2-methylphenyl)imino]-1,1-dioxoguanidine top

Crystal data top

C₁₅H₁₅N₅O₂	F(000) = 1248
M_r = 297.32	D_x = 1.366 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 8384 reflections
a = 14.6525 (3) Å	θ = 2.7–28.3°
b = 10.2523 (3) Å	µ = 0.10 mm⁻¹
c = 19.2425 (4) Å	T = 200 K
V = 2890.64 (12) Å³	Needle, red
Z = 8	0.43 × 0.19 × 0.19 mm

Data collection top

Bruker APEXII CCD diffractometer	3619 independent reflections
Graphite monochromator	2487 reflections with I > 2σ(I)
Detector resolution: 8.4 pixels mm^-1	R_int = 0.028
ω and ϕ scans	θ_max = 28.4°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −19→19
T_min = 0.960, T_max = 0.982	k = −12→13
24031 measured reflections	l = −25→25

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)] = 0.060	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.180	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.070P)² + 1.8629P] where P = (F_o² + 2F_c²)/3
3619 reflections	(Δ/σ)_max < 0.001
221 parameters	Δρ_max = 0.51 e Å⁻³
48 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₁₅H₁₅N₅O₂	V = 2890.64 (12) Å³
M_r = 297.32	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 14.6525 (3) Å	µ = 0.10 mm⁻¹
b = 10.2523 (3) Å	T = 200 K
c = 19.2425 (4) Å	0.43 × 0.19 × 0.19 mm

Data collection top

Bruker APEXII CCD diffractometer	3619 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2008)	2487 reflections with I > 2σ(I)
T_min = 0.960, T_max = 0.982	R_int = 0.028
24031 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.060	48 restraints
wR(F²) = 0.180	H-atom parameters constrained
S = 1.05	Δρ_max = 0.51 e Å⁻³
3619 reflections	Δρ_min = −0.21 e Å⁻³
221 parameters

Special details top

Experimental. The intensity data was collected on a Bruker APEX-II CCD diffractometer using an exposure time of 60 s/frame. A total of 1062 frames were collected with a frame width of 0.5° covering up to θ = 28.40° with 99.6% completeness accomplished.

Analytical data: M.p. 154 °C. λ_max (dichloromethane) 319, 440 nm. ¹H (600 MHz, CDCl₃) 14.32 (1 H, 1 × s, 1 × NH), 2.58 (6 H, 1 × s, 2 × CH₃), 7.92 – 7.29 (8 H, 2 × m, 2 × C₆H₄)

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	Occ. (<1)
N1	0.26169 (12)	0.01378 (16)	0.07679 (8)	0.0441 (4)
HN1	0.2252	0.0663	0.0999	0.053*	0.53 (3)
N2	0.34854 (12)	0.01558 (17)	0.08281 (8)	0.0458 (4)
N3	0.35427 (11)	0.19544 (16)	0.16744 (8)	0.0408 (4)
N4	0.26631 (10)	0.21162 (16)	0.17126 (8)	0.0385 (4)
HN4	0.2283	0.1648	0.1462	0.046*	0.47 (3)
N5	0.48561 (13)	0.0936 (2)	0.12737 (11)	0.0580 (5)
O1A	0.5222 (5)	−0.0056 (8)	0.1083 (9)	0.094 (3)	0.75 (4)
O2A	0.5302 (5)	0.1873 (10)	0.1454 (10)	0.087 (3)	0.75 (4)
O1B	0.512 (2)	0.012 (3)	0.087 (2)	0.107 (8)	0.25 (4)
O2B	0.5218 (19)	0.155 (4)	0.172 (2)	0.097 (6)	0.25 (4)
C1	0.07297 (15)	−0.0431 (3)	0.07535 (13)	0.0596 (6)
H1A	0.092	−0.0557	0.1237	0.089*
H1B	0.0118	−0.0797	0.0687	0.089*
H1C	0.072	0.0503	0.0646	0.089*
C2	0.13763 (15)	−0.1095 (2)	0.02891 (10)	0.0485 (5)
C3	0.10754 (17)	−0.2092 (2)	−0.01616 (11)	0.0549 (6)
H3	0.0448	−0.2327	−0.0162	0.066*
C4	0.16569 (18)	−0.2723 (2)	−0.05938 (12)	0.0590 (6)
H4	0.1436	−0.3392	−0.0891	0.071*
C5	0.25748 (19)	−0.2394 (2)	−0.06022 (12)	0.0629 (6)
H5	0.2978	−0.2822	−0.0915	0.075*
C6	0.28997 (16)	−0.1465 (2)	−0.01666 (11)	0.0543 (5)
H6	0.353	−0.1251	−0.0169	0.065*
C7	0.22993 (15)	−0.0819 (2)	0.02888 (10)	0.0464 (5)
C8	0.38492 (13)	0.1033 (2)	0.12568 (9)	0.0425 (4)
C9	0.23522 (12)	0.30827 (18)	0.21773 (9)	0.0375 (4)
C10	0.29585 (14)	0.3870 (2)	0.25478 (10)	0.0448 (5)
H10	0.3598	0.3751	0.2496	0.054*
C11	0.26305 (16)	0.4823 (2)	0.29902 (10)	0.0501 (5)
H11	0.3043	0.5367	0.3238	0.06*
C12	0.16987 (16)	0.4981 (2)	0.30707 (11)	0.0510 (5)
H12	0.1469	0.5632	0.3375	0.061*
C13	0.11046 (15)	0.4192 (2)	0.27091 (11)	0.0511 (5)
H13	0.0467	0.431	0.2771	0.061*
C14	0.14087 (13)	0.3228 (2)	0.22551 (10)	0.0429 (4)
C15	0.07500 (14)	0.2388 (3)	0.18674 (14)	0.0619 (6)
H15A	0.0125	0.2619	0.2001	0.093*
H15B	0.0864	0.147	0.198	0.093*
H15C	0.0829	0.2523	0.1367	0.093*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0552 (10)	0.0391 (9)	0.0381 (8)	−0.0027 (7)	−0.0009 (7)	0.0037 (7)
N2	0.0527 (9)	0.0440 (9)	0.0405 (8)	0.0019 (8)	0.0020 (7)	0.0042 (7)
N3	0.0402 (8)	0.0431 (9)	0.0392 (8)	0.0031 (7)	0.0009 (6)	0.0042 (7)
N4	0.0381 (8)	0.0405 (9)	0.0369 (7)	0.0013 (6)	0.0012 (6)	0.0042 (6)
N5	0.0436 (10)	0.0637 (13)	0.0666 (12)	0.0095 (9)	0.0059 (9)	−0.0043 (10)
O1A	0.045 (2)	0.070 (3)	0.168 (7)	0.0139 (19)	0.001 (3)	−0.030 (3)
O2A	0.0410 (16)	0.094 (4)	0.125 (6)	−0.0035 (18)	−0.004 (3)	−0.048 (4)
O1B	0.085 (11)	0.124 (13)	0.112 (14)	0.049 (10)	0.039 (9)	−0.025 (9)
O2B	0.049 (7)	0.141 (14)	0.101 (12)	−0.003 (8)	−0.011 (8)	−0.027 (11)
C1	0.0484 (12)	0.0678 (15)	0.0626 (13)	−0.0005 (11)	−0.0058 (10)	−0.0057 (12)
C2	0.0552 (12)	0.0461 (12)	0.0440 (10)	0.0007 (9)	0.0014 (9)	0.0074 (9)
C3	0.0651 (13)	0.0518 (13)	0.0479 (11)	−0.0098 (11)	−0.0066 (10)	0.0042 (10)
C4	0.0763 (15)	0.0480 (13)	0.0528 (12)	−0.0119 (11)	−0.0020 (11)	−0.0008 (10)
C5	0.0755 (16)	0.0577 (14)	0.0555 (13)	−0.0040 (12)	0.0140 (12)	−0.0069 (11)
C6	0.0601 (13)	0.0548 (13)	0.0481 (11)	−0.0088 (10)	0.0075 (9)	−0.0021 (10)
C7	0.0567 (12)	0.0431 (11)	0.0394 (9)	−0.0034 (9)	−0.0013 (8)	0.0056 (8)
C8	0.0400 (9)	0.0454 (11)	0.0420 (9)	0.0042 (8)	0.0020 (8)	0.0043 (8)
C9	0.0431 (9)	0.0360 (9)	0.0334 (8)	0.0018 (7)	0.0008 (7)	0.0066 (7)
C10	0.0465 (10)	0.0472 (11)	0.0407 (9)	−0.0020 (9)	−0.0003 (8)	0.0031 (8)
C11	0.0625 (13)	0.0466 (12)	0.0413 (10)	−0.0026 (10)	−0.0034 (9)	0.0009 (9)
C12	0.0644 (13)	0.0438 (12)	0.0449 (11)	0.0059 (10)	0.0036 (9)	−0.0019 (9)
C13	0.0495 (11)	0.0474 (12)	0.0564 (12)	0.0082 (9)	0.0065 (9)	0.0001 (10)
C14	0.0438 (10)	0.0404 (10)	0.0445 (10)	0.0035 (8)	0.0008 (8)	0.0029 (8)
C15	0.0408 (10)	0.0639 (15)	0.0811 (16)	0.0020 (10)	−0.0016 (10)	−0.0208 (13)

Geometric parameters (Å, º) top

N1—N2	1.278 (2)	C4—C5	1.387 (4)
N1—C7	1.424 (3)	C4—H4	0.95
N1—HN1	0.88	C5—C6	1.355 (3)
N2—C8	1.332 (3)	C5—H5	0.95
N3—N4	1.302 (2)	C6—C7	1.407 (3)
N3—C8	1.319 (2)	C6—H6	0.95
N4—C9	1.410 (2)	C9—C10	1.396 (3)
N4—HN4	0.88	C9—C14	1.399 (3)
N5—O2B	1.192 (13)	C10—C11	1.382 (3)
N5—O1A	1.208 (5)	C10—H10	0.95
N5—O1B	1.210 (13)	C11—C12	1.384 (3)
N5—O2A	1.212 (6)	C11—H11	0.95
N5—C8	1.479 (3)	C12—C13	1.377 (3)
C1—C2	1.470 (3)	C12—H12	0.95
C1—H1A	0.98	C13—C14	1.392 (3)
C1—H1B	0.98	C13—H13	0.95
C1—H1C	0.98	C14—C15	1.494 (3)
C2—C7	1.382 (3)	C15—H15A	0.98
C2—C3	1.411 (3)	C15—H15B	0.98
C3—C4	1.355 (3)	C15—H15C	0.98
C3—H3	0.95

N2—N1—C7	113.21 (17)	C5—C6—C7	119.8 (2)
N2—N1—HN1	123.4	C5—C6—H6	120.1
C7—N1—HN1	123.4	C7—C6—H6	120.1
N1—N2—C8	117.68 (17)	C2—C7—C6	121.0 (2)
N4—N3—C8	117.57 (16)	C2—C7—N1	117.44 (19)
N3—N4—C9	116.44 (15)	C6—C7—N1	121.53 (19)
N3—N4—HN4	121.8	N3—C8—N2	136.45 (18)
C9—N4—HN4	121.8	N3—C8—N5	111.97 (17)
O2B—N5—O1A	117.8 (14)	N2—C8—N5	111.57 (17)
O2B—N5—O1B	134 (2)	C10—C9—C14	120.83 (18)
O1A—N5—O2A	121.0 (5)	C10—C9—N4	121.64 (17)
O1B—N5—O2A	124.2 (14)	C14—C9—N4	117.53 (16)
O2B—N5—C8	115.1 (14)	C11—C10—C9	120.14 (19)
O1A—N5—C8	119.5 (4)	C11—C10—H10	119.9
O1B—N5—C8	110.4 (16)	C9—C10—H10	119.9
O2A—N5—C8	119.4 (4)	C10—C11—C12	119.6 (2)
C2—C1—H1A	109.5	C10—C11—H11	120.2
C2—C1—H1B	109.5	C12—C11—H11	120.2
H1A—C1—H1B	109.5	C13—C12—C11	119.9 (2)
C2—C1—H1C	109.5	C13—C12—H12	120
H1A—C1—H1C	109.5	C11—C12—H12	120
H1B—C1—H1C	109.5	C12—C13—C14	122.1 (2)
C7—C2—C3	117.0 (2)	C12—C13—H13	118.9
C7—C2—C1	122.4 (2)	C14—C13—H13	118.9
C3—C2—C1	120.5 (2)	C13—C14—C9	117.34 (18)
C4—C3—C2	121.8 (2)	C13—C14—C15	121.07 (19)
C4—C3—H3	119.1	C9—C14—C15	121.59 (18)
C2—C3—H3	119.1	C14—C15—H15A	109.5
C3—C4—C5	120.0 (2)	C14—C15—H15B	109.5
C3—C4—H4	120	H15A—C15—H15B	109.5
C5—C4—H4	120	C14—C15—H15C	109.5
C6—C5—C4	120.3 (2)	H15A—C15—H15C	109.5
C6—C5—H5	119.8	H15B—C15—H15C	109.5
C4—C5—H5	119.8

C7—N1—N2—C8	178.96 (16)	O1A—N5—C8—N3	159.5 (10)
C8—N3—N4—C9	178.28 (15)	O1B—N5—C8—N3	−177 (2)
C7—C2—C3—C4	−2.2 (3)	O2A—N5—C8—N3	−23.3 (11)
C1—C2—C3—C4	−179.8 (2)	O2B—N5—C8—N2	−169 (3)
C2—C3—C4—C5	−0.1 (4)	O1A—N5—C8—N2	−19.9 (10)
C3—C4—C5—C6	1.7 (4)	O1B—N5—C8—N2	3 (2)
C4—C5—C6—C7	−0.9 (4)	O2A—N5—C8—N2	157.4 (11)
C3—C2—C7—C6	3.0 (3)	N3—N4—C9—C10	3.3 (2)
C1—C2—C7—C6	−179.5 (2)	N3—N4—C9—C14	−176.70 (16)
C3—C2—C7—N1	−176.77 (17)	C14—C9—C10—C11	−1.0 (3)
C1—C2—C7—N1	0.8 (3)	N4—C9—C10—C11	178.91 (17)
C5—C6—C7—C2	−1.5 (3)	C9—C10—C11—C12	0.8 (3)
C5—C6—C7—N1	178.3 (2)	C10—C11—C12—C13	−0.2 (3)
N2—N1—C7—C2	167.38 (17)	C11—C12—C13—C14	−0.3 (3)
N2—N1—C7—C6	−12.4 (3)	C12—C13—C14—C9	0.1 (3)
N4—N3—C8—N2	0.3 (3)	C12—C13—C14—C15	−179.8 (2)
N4—N3—C8—N5	−178.83 (16)	C10—C9—C14—C13	0.6 (3)
N1—N2—C8—N3	0.8 (3)	N4—C9—C14—C13	−179.37 (16)
N1—N2—C8—N5	179.90 (16)	C10—C9—C14—C15	−179.5 (2)
O2B—N5—C8—N3	11 (3)	N4—C9—C14—C15	0.5 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O1Aⁱ	0.95	2.42	3.239 (9)	145

Symmetry code: (i) x−1/2, −y−1/2, −z.

Experimental details

Crystal data
Chemical formula	C₁₅H₁₅N₅O₂
M_r	297.32
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	200
a, b, c (Å)	14.6525 (3), 10.2523 (3), 19.2425 (4)
V (Å³)	2890.64 (12)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.43 × 0.19 × 0.19

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2008)
T_min, T_max	0.960, 0.982
No. of measured, independent and observed [I > 2σ(I)] reflections	24031, 3619, 2487
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.669

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.060, 0.180, 1.05
No. of reflections	3619
No. of parameters	221
No. of restraints	48
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.51, −0.21

Computer programs: APEX2 (Bruker, 2011), SAINT (Bruker, 2008), SAINT and XPREP (Bruker, 2008), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O1Aⁱ	0.95	2.42	3.239 (9)	145

Symmetry code: (i) x−1/2, −y−1/2, −z.

Table 2. Short π···π interaction geometries (°, Å) top

Cg(X)···Cg(Y)	Cg···Cg	Alpha	Beta	Gamma	Cg(X)perp	Cg(X)perp
Cg1···Cg2ⁱ	3.4813	7.215	4.85	12.04	3.4047	-3.4688
Cg1···Cg3ⁱ	3.3976	2.589	3.11	3.37	-3.3917	3.3925

For centroids: Cg1 = N₁—N₂═C₈—N₃═N₄, Cg2 = ring C₂ – C₇, Cg3 = ring C₉ – C₁₄; Symmetry codes: i = 1/2-X,1/2+Y,Z; Alpha = Dihedral angle between Cg(X) and Cg(Y); Cg(X)perp = Perpendicular distance of Cg(X) on ring Y; Cg(X)perp = Perpendicular distance of Cg(Y) on ring X; Beta = Angle Cg(X)···Cg(Y) vector and normal to ring X; Gamma = Angle Cg(I)···Cg(J) vector and normal to plane Y;

Acknowledgements

Research funds of the Universities of Johannesburg, Free State and Port Elizabeth, and the National Research Foundation of South Africa are gratefully acknowledged.

References

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