4,5-Diiodo-2-phenyl-1H-imidazole

Chlupatý, T.; Pařík, P.; Padělková, Z.

doi:10.1107/S1600536812003017

organic compounds

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ISSN: 2056-9890

Volume 68| Part 2| February 2012| Pages o553-o554

doi:10.1107/S1600536812003017

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4,5-Diiodo-2-phenyl-1H-imidazole

Tomáš Chlupatý,^a Patrik Pařík ^b and Zdeňka Padělková ^a ^*

^aDepartment of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic, and ^bInstitute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic
^*Correspondence e-mail: zdenka.padelkova@upce.cz

(Received 20 December 2011; accepted 24 January 2012; online 31 January 2012)

The structure of the title compound, C₉H₆I₂N₂, contains two symmetry-independent molecules. The interplanar angles between the imidazole and phenyl ring planes are 16.35 (3) and 17.48 (6)°. Molecules are connected via N—H⋯N hydrogen bonds to form zigzag chains along the b axis. The title compound is the first example of a structurally characterized 4,5-diiodoimidazole with an organic substituent in the 2-position and without protection on the N—H group of imidazole.

Related literature

For the structures of various related compounds, see: Delest et al. (2008 ); Poverlein et al. (2007 ); Panday et al. (2000 ); Phillips et al. (1997 ); Terinek & Vasella (2003 ); Mukai & Nishikawa (2010a ,b ); Noland et al. (2003 ); Dou & Weiss (1992 ); Nagatomo et al. (1995 ). For the use of diiodoimidazoles as starting compounds for ligand synthesis, see: Haruki et al. (1965 ); Ito & Uedaira (2004 ); Kim et al. (1999 ); Zhang et al. (2006 ). For the synthetic procedure, see: Garden et al. (2001 ); Ishihara & Togo (2006 ). For typical bond lengths, see: Allen et al. (1987 ).

Experimental

Crystal data

C₉H₆I₂N₂
M_r = 395.96
Orthorhombic, A b a 2
a = 31.0150 (6) Å
b = 17.5010 (5) Å
c = 8.0461 (9) Å
V = 4367.4 (5) Å³
Z = 16
Mo Kα radiation
μ = 5.72 mm⁻¹
T = 150 K
0.45 × 0.16 × 0.07 mm

Data collection

Bruker–Nonius KappaCCD area-detector diffractometer
Absorption correction: gaussian (Coppens, 1970 ) T_min = 0.256, T_max = 0.675
20468 measured reflections
4914 independent reflections
4499 reflections with I > 2σ(I)
R_int = 0.058

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.051
S = 1.04
4914 reflections
235 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.63 e Å⁻³
Δρ_min = −0.63 e Å⁻³
Absolute structure: Flack (1983 ), 2233 Friedel pairs
Flack parameter: 0.01 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯N3ⁱ	0.86	2.01	2.845 (5)	165
N4—H4⋯N1	0.86	2.02	2.848 (6)	162
Symmetry code: (i) $[x, y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: COLLECT (Hooft, 1998 ) and DENZO (Otwinowski & Minor, 1997 ); cell refinement: COLLECT and DENZO; data reduction: COLLECT and DENZO; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: PLATON (Spek, 2009 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812003017/im2350sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812003017/im2350Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812003017/im2350Isup3.cml

checkCIF report

Comment top

Halogenated derivatives of heterocycles are important starting compounds for building new heterocyclic chiral ligands via cross-coupling reactions. In recent times 4,5-diiodoimidazole and its derivatives were used for the preparation of various disubstituted 4,5-dicarbaimidazoles (Zhang et al., 2006; Ito & Uedaira, 2004; Kim et al., 1999; Haruki et al., 1965). To the best of our knowledge, there are a couple of structures of dihalogenated imidazoles determined by X-ray diffraction methods, but the 4,5-diido-1H-imidazole structure as the most versatile and simpliest member of the series is missing. Compound I (Scheme 1) was separated as a byproduct from a reaction described by Ishihara (Ishihara & Togo, 2006) but is usually prepared by the method of Garden (Garden et al., 2001). The title compound crystallizes (Fig. 1) in an orthorhombic space group with two independent molecules in the unit cell (Fig. 2). Both molecules reveal similar structural behavior showing two planar conjugated rings – phenyl and imidazolyl. The interplanar angles between imidazolyl and phenyl planes are 16.35 (3)° and 17.48 (6)°, respectively. The formation of infinite chains is provided by the connection of both types of molecules via N–H···N hydrogen bridges. The linear chains interact via the iodine atoms at neighbouring imidazole moieties. In contrast to typical C–I bond lenghts of ca. 2.095 Å (Allen et al., 1987) which is the same for monoiodoimidazoles, the C–I separations in diiodoimidazoles significantly differ between ca. 2.05 and 2.09 Å (Panday et al., 2000; Terinek & Vasella, 2003). This phenomenon is also seen in one of the molecules of I, where the C11–I3 bond length is 2.075 (5) Å and the C12–I4 bond located next to the N–H function is shortened to 2.058 (5) Å. On the other hand, in the first molecule both C–I bond lenghts (2.051 (5) and 2.058 (5) Å) are almost identical and thus comparable to the same parameters found in compounds containing the 4,5-diidoimidazolium ion (Mukai & Nishikawa, 2010a,b). Only one iodine atom I1 is located in the same plane defined by the imidazole ring, while the others show deviations of 0.07-0.148 Å. Bond lenghts between the atoms forming the imidazole rings are comparable to literature values (Allen et al., 1987) except of C1–N2 which is elongated by 0.02 Å and C10–N3 which is slightly shortened.

Related literature top

For the structures of various related compounds, see: Delest et al. (2008); Poverlein et al. (2007); Panday et al. (2000); Phillips et al. (1997); Terinek & Vasella (2003); Mukai & Nishikawa (2010a,b); Noland et al. (2003); Dou & Weiss (1992); Nagatomo et al. (1995). For the use of diiodoimidazoles as starting compounds for ligand synthesis, see: Haruki et al. (1965); Ito & Uedaira (2004); Kim et al. (1999); Zhang et al. (2006). For the synthetic procedure, see: Garden et al. (2001); Ishihara & Togo (2006). For typical bond lengths, see: Allen et al. (1987).

Experimental top

The title compound I was isolated in 30% yield as a byproduct from the reaction mixture of 2-phenyl-1H-imidazole-4-carbaldehyde with ethan-1,2-diamine, iodine and potassium carbonate in tert-butylalcohol, according to Ishihara (Ishihara & Togo, 2006) in order to prepare 2'-phenyl-4,5-dihydro-1H,1'H-2,4'-biimidazole. The reaction mixture was separated by the help of column chromatography on silicagel (ethyl acetate, hexane and dichloromethane – 1:3:10). Further crystallization from dichloromethane gave pure I. The identity and purity of I was confirmed by the same melting point, ¹H NMR and mass spectra patterns as published elsewhere (Garden et al., 2001). Single crystals of I were obtained by slow vapour diffussion of hexane into a solution of I in dichloromethane.

Computing details top

Data collection: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); cell refinement: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); data reduction: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. View of one of the independent molecules of the title compound with the displacement ellipsoids shown at the 50% probability level. H atoms are shown with arbitrary radii.
	Fig. 2. View of the crystal structure down the c axis showing the hydrogen bond interactions.

4,5-Diiodo-2-phenyl-1H-imidazole top

Crystal data top

C₉H₆I₂N₂	D_x = 2.409 Mg m⁻³
M_r = 395.96	Melting point: 472 K
Orthorhombic, Aba2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: A 2 -2ac	Cell parameters from 20579 reflections
a = 31.0150 (6) Å	θ = 1–27.5°
b = 17.5010 (5) Å	µ = 5.72 mm⁻¹
c = 8.0461 (9) Å	T = 150 K
V = 4367.4 (5) Å³	Needle, colourless
Z = 16	0.45 × 0.16 × 0.07 mm
F(000) = 2880

Data collection top

Bruker–Nonius KappaCCD area-detector diffractometer	4914 independent reflections
Radiation source: fine-focus sealed tube	4499 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.058
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.5°, θ_min = 2.3°
ϕ and ω scans to fill the Ewald sphere	h = −39→40
Absorption correction: gaussian (Coppens, 1970)	k = −22→19
T_min = 0.256, T_max = 0.675	l = −9→10
20468 measured reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.029	H-atom parameters constrained
wR(F²) = 0.051	w = 1/[σ²(F_o²) + (0.0196P)² + 8.5806P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max = 0.001
4914 reflections	Δρ_max = 0.63 e Å⁻³
235 parameters	Δρ_min = −0.63 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 2233 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.01 (3)

Crystal data top

C₉H₆I₂N₂	V = 4367.4 (5) Å³
M_r = 395.96	Z = 16
Orthorhombic, Aba2	Mo Kα radiation
a = 31.0150 (6) Å	µ = 5.72 mm⁻¹
b = 17.5010 (5) Å	T = 150 K
c = 8.0461 (9) Å	0.45 × 0.16 × 0.07 mm

Data collection top

Bruker–Nonius KappaCCD area-detector diffractometer	4914 independent reflections
Absorption correction: gaussian (Coppens, 1970)	4499 reflections with I > 2σ(I)
T_min = 0.256, T_max = 0.675	R_int = 0.058
20468 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.029	H-atom parameters constrained
wR(F²) = 0.051	Δρ_max = 0.63 e Å⁻³
S = 1.04	Δρ_min = −0.63 e Å⁻³
4914 reflections	Absolute structure: Flack (1983), 2233 Friedel pairs
235 parameters	Absolute structure parameter: 0.01 (3)
1 restraint

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
I3	0.239603 (10)	0.127609 (18)	0.00147 (5)	0.02406 (8)
I2	0.185474 (11)	0.465127 (18)	0.86344 (5)	0.02557 (9)
I1	0.142369 (12)	0.262855 (18)	0.73764 (5)	0.02639 (9)
I4	0.225974 (10)	0.324363 (17)	0.26443 (4)	0.02035 (8)
N1	0.11736 (13)	0.3687 (2)	0.4558 (5)	0.0172 (9)
N3	0.14573 (13)	0.1439 (2)	0.0814 (5)	0.0160 (8)
C14	0.05141 (17)	0.1305 (3)	0.0519 (7)	0.0210 (12)
H14	0.0683	0.1040	−0.0242	0.025*
C9	0.11213 (17)	0.5450 (3)	0.2022 (6)	0.0217 (12)
H9	0.1321	0.5741	0.2610	0.026*
C3	0.15163 (16)	0.4339 (3)	0.6553 (6)	0.0166 (10)
C1	0.11925 (16)	0.4415 (3)	0.4126 (6)	0.0153 (10)
C4	0.10087 (15)	0.4731 (2)	0.2585 (7)	0.0178 (10)
C13	0.07108 (16)	0.1796 (3)	0.1643 (6)	0.0151 (10)
C11	0.18543 (15)	0.1775 (3)	0.1070 (6)	0.0163 (10)
C2	0.13758 (15)	0.3637 (3)	0.6074 (6)	0.0146 (10)
C12	0.18168 (16)	0.2429 (3)	0.1949 (6)	0.0170 (10)
C10	0.11796 (16)	0.1907 (3)	0.1591 (6)	0.0150 (10)
N2	0.13961 (13)	0.4833 (2)	0.5321 (5)	0.0184 (9)
H2	0.1441	0.5318	0.5297	0.022*
C18	0.04545 (16)	0.2180 (3)	0.2794 (7)	0.0219 (11)
H18	0.0582	0.2511	0.3556	0.026*
C5	0.07161 (18)	0.4297 (3)	0.1697 (7)	0.0269 (13)
H5	0.0637	0.3815	0.2079	0.032*
C16	−0.01789 (19)	0.1579 (3)	0.1692 (8)	0.0301 (14)
H16	−0.0476	0.1507	0.1714	0.036*
N4	0.13889 (12)	0.2501 (2)	0.2280 (6)	0.0147 (8)
H4	0.1273	0.2867	0.2834	0.018*
C17	0.00127 (17)	0.2077 (3)	0.2786 (8)	0.0296 (13)
H17	−0.0156	0.2343	0.3548	0.035*
C15	0.00750 (18)	0.1195 (3)	0.0545 (8)	0.0284 (13)
H15	−0.0053	0.0865	−0.0215	0.034*
C8	0.0937 (2)	0.5739 (3)	0.0577 (7)	0.0313 (14)
H8	0.1005	0.6230	0.0224	0.038*
C7	0.0656 (2)	0.5299 (3)	−0.0314 (8)	0.0343 (15)
H7	0.0542	0.5487	−0.1302	0.041*
C6	0.0541 (2)	0.4581 (3)	0.0261 (8)	0.0347 (15)
H6	0.0350	0.4285	−0.0352	0.042*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I3	0.02447 (18)	0.02458 (16)	0.02313 (18)	0.00572 (12)	0.00691 (17)	−0.00173 (16)
I2	0.03117 (19)	0.02441 (17)	0.02114 (18)	0.00247 (14)	−0.01031 (16)	−0.00504 (16)
I1	0.0322 (2)	0.01704 (15)	0.0299 (2)	−0.00235 (14)	−0.00951 (16)	0.00849 (16)
I4	0.01828 (16)	0.01997 (15)	0.02279 (17)	−0.00410 (12)	−0.00100 (14)	−0.00314 (15)
N1	0.019 (2)	0.012 (2)	0.020 (2)	0.0002 (16)	−0.0024 (17)	−0.0020 (17)
N3	0.022 (2)	0.0113 (19)	0.014 (2)	0.0012 (16)	−0.0021 (17)	−0.0004 (17)
C14	0.023 (3)	0.019 (3)	0.021 (3)	0.003 (2)	−0.003 (2)	−0.002 (2)
C9	0.030 (3)	0.018 (3)	0.017 (3)	−0.003 (2)	−0.001 (2)	0.000 (2)
C3	0.016 (2)	0.017 (2)	0.017 (3)	−0.0009 (19)	−0.002 (2)	0.001 (2)
C1	0.019 (3)	0.013 (2)	0.014 (3)	−0.0019 (19)	−0.0007 (19)	0.0012 (19)
C4	0.020 (2)	0.019 (2)	0.014 (3)	0.0032 (19)	0.002 (2)	0.000 (2)
C13	0.021 (3)	0.011 (2)	0.014 (3)	0.0038 (18)	−0.006 (2)	0.0051 (19)
C11	0.019 (2)	0.013 (2)	0.017 (3)	0.0060 (18)	0.004 (2)	−0.001 (2)
C2	0.015 (2)	0.015 (2)	0.014 (3)	0.0024 (18)	0.003 (2)	0.0008 (19)
C12	0.018 (3)	0.014 (2)	0.019 (3)	−0.0025 (19)	0.001 (2)	0.001 (2)
C10	0.024 (3)	0.010 (2)	0.012 (2)	−0.0031 (18)	−0.001 (2)	−0.0004 (18)
N2	0.024 (2)	0.0103 (19)	0.021 (3)	0.0011 (16)	−0.0028 (18)	−0.0033 (17)
C18	0.022 (3)	0.018 (2)	0.027 (3)	0.0016 (19)	−0.001 (2)	−0.001 (2)
C5	0.028 (3)	0.019 (3)	0.034 (3)	−0.003 (2)	−0.008 (2)	0.005 (2)
C16	0.020 (3)	0.037 (3)	0.033 (4)	−0.008 (2)	−0.002 (3)	0.001 (3)
N4	0.017 (2)	0.0127 (18)	0.014 (2)	0.0015 (15)	−0.0053 (17)	−0.0043 (17)
C17	0.017 (3)	0.034 (3)	0.038 (4)	−0.001 (2)	0.002 (3)	0.002 (3)
C15	0.023 (3)	0.031 (3)	0.031 (3)	−0.006 (2)	−0.010 (2)	0.000 (2)
C8	0.045 (4)	0.024 (3)	0.026 (3)	−0.006 (2)	−0.009 (3)	0.007 (2)
C7	0.047 (4)	0.030 (3)	0.026 (4)	0.003 (3)	−0.015 (3)	0.009 (3)
C6	0.044 (4)	0.030 (3)	0.030 (4)	−0.013 (2)	−0.020 (3)	0.004 (3)

Geometric parameters (Å, º) top

I3—C11	2.075 (5)	C13—C10	1.467 (7)
I2—C3	2.051 (5)	C11—C12	1.350 (7)
I1—C2	2.058 (5)	C12—N4	1.360 (6)
I4—C12	2.058 (5)	C10—N4	1.345 (6)
N1—C1	1.323 (6)	N2—H2	0.8600
N1—C2	1.374 (6)	C18—C17	1.382 (7)
N3—C10	1.343 (6)	C18—H18	0.9300
N3—C11	1.379 (6)	C5—C6	1.370 (8)
C14—C15	1.376 (8)	C5—H5	0.9302
C14—C13	1.388 (7)	C16—C17	1.374 (8)
C14—H14	0.9301	C16—C15	1.388 (9)
C9—C4	1.381 (7)	C16—H16	0.9299
C9—C8	1.391 (8)	N4—H4	0.8600
C9—H9	0.9301	C17—H17	0.9300
C3—C2	1.360 (7)	C15—H15	0.9299
C3—N2	1.366 (6)	C8—C7	1.367 (8)
C1—N2	1.363 (6)	C8—H8	0.9301
C1—C4	1.472 (7)	C7—C6	1.385 (8)
C4—C5	1.383 (7)	C7—H7	0.9299
C13—C18	1.393 (7)	C6—H6	0.9299

C1—N1—C2	105.9 (4)	N4—C10—C13	124.7 (4)
C10—N3—C11	104.1 (4)	C1—N2—C3	107.4 (4)
C15—C14—C13	120.8 (5)	C1—N2—H2	126.0
C15—C14—H14	119.8	C3—N2—H2	126.6
C13—C14—H14	119.3	C17—C18—C13	120.0 (5)
C4—C9—C8	120.1 (5)	C17—C18—H18	120.3
C4—C9—H9	119.9	C13—C18—H18	119.8
C8—C9—H9	120.0	C6—C5—C4	119.8 (5)
C2—C3—N2	106.2 (4)	C6—C5—H5	120.3
C2—C3—I2	129.5 (4)	C4—C5—H5	120.0
N2—C3—I2	124.3 (3)	C17—C16—C15	119.2 (5)
N1—C1—N2	110.6 (4)	C17—C16—H16	120.2
N1—C1—C4	124.5 (4)	C15—C16—H16	120.6
N2—C1—C4	124.9 (4)	C10—N4—C12	108.6 (4)
C9—C4—C5	119.8 (5)	C10—N4—H4	126.0
C9—C4—C1	121.4 (4)	C12—N4—H4	125.4
C5—C4—C1	118.9 (4)	C16—C17—C18	121.0 (5)
C14—C13—C18	118.7 (5)	C16—C17—H17	119.8
C14—C13—C10	119.9 (4)	C18—C17—H17	119.2
C18—C13—C10	121.4 (4)	C14—C15—C16	120.2 (5)
C12—C11—N3	111.2 (4)	C14—C15—H15	120.0
C12—C11—I3	129.8 (4)	C16—C15—H15	119.7
N3—C11—I3	118.9 (3)	C7—C8—C9	119.8 (5)
C3—C2—N1	109.9 (4)	C7—C8—H8	120.4
C3—C2—I1	127.4 (4)	C9—C8—H8	119.9
N1—C2—I1	122.6 (3)	C8—C7—C6	119.9 (5)
C11—C12—N4	105.4 (4)	C8—C7—H7	119.4
C11—C12—I4	132.2 (4)	C6—C7—H7	120.6
N4—C12—I4	122.3 (3)	C5—C6—C7	120.6 (5)
N3—C10—N4	110.7 (4)	C5—C6—H6	119.9
N3—C10—C13	124.6 (4)	C7—C6—H6	119.4

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N3ⁱ	0.86	2.01	2.845 (5)	165
N4—H4···N1	0.86	2.02	2.848 (6)	162

Symmetry code: (i) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₉H₆I₂N₂
M_r	395.96
Crystal system, space group	Orthorhombic, Aba2
Temperature (K)	150
a, b, c (Å)	31.0150 (6), 17.5010 (5), 8.0461 (9)
V (Å³)	4367.4 (5)
Z	16
Radiation type	Mo Kα
µ (mm⁻¹)	5.72
Crystal size (mm)	0.45 × 0.16 × 0.07

Data collection
Diffractometer	Bruker–Nonius KappaCCD area-detector diffractometer
Absorption correction	Gaussian (Coppens, 1970)
T_min, T_max	0.256, 0.675
No. of measured, independent and observed [I > 2σ(I)] reflections	20468, 4914, 4499
R_int	0.058
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.051, 1.04
No. of reflections	4914
No. of parameters	235
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.63, −0.63
Absolute structure	Flack (1983), 2233 Friedel pairs
Absolute structure parameter	0.01 (3)

Computer programs: COLLECT (Hooft, 1998) and DENZO (Otwinowski & Minor, 1997), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···N3ⁱ	0.86	2.01	2.845 (5)	164.7
N4—H4···N1	0.86	2.02	2.848 (6)	161.7

Symmetry code: (i) x, y+1/2, z+1/2.

Acknowledgements

The authors thank the Czech Science Foundation (Project P207/12/0223) for the financial support of this work.

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