Amino­[(1H-benzimidazol-2-yl)amino]­methaniminium 4-methyl­benzene­sulfonate

Shaaban K Mohamed; Mehmet Akkurt; Mahmoud A A Elremaily; Ali M Ali; Mustafa R Albayati

doi:10.1107/S1600536813024975

. 2013 Sep 18;69(Pt 10):o1543–o1544. doi: 10.1107/S1600536813024975

Amino[(1H-benzimidazol-2-yl)amino]methaniminium 4-methylbenzenesulfonate

Shaaban K Mohamed ^a,^b, Mehmet Akkurt ^c, Mahmoud A A Elremaily ^d,^e, Ali M Ali ^d,^e, Mustafa R Albayati ^f,^*

PMCID: PMC3790410 PMID: 24098229

Abstract

The asymmetric unit of the title salt, C₈H₁₀N₅ ⁺·C₇H₇O₃S⁻, consists of two amino[(1H-benzimidazol-2-yl)amino]methaniminium cations and two 4-methylbenzenesulfonate anions. The cations are each stabilized by intramolecular N—H⋯N hydrogen bonds between the free amino groups and the imine N atoms of the benzimidazole units, forming S(6) ring motifs. In the crystal, cations and anions are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional supramolecular framework. Two strong π–π stacking interactions [centroid–centroid distances = 3.4112 (14) and 3.4104 (14) Å] also occur between the centroids of the imidazole rings of like cations.

Related literature

For the synthesis of guanidine-containing compounds, see: Wu et al. (2002 ▶); Hopkins et al. (2002 ▶); Kilburn et al. (2002 ▶); Manimala & Anslyn (2002 ▶). For pharmaceutical and chemical applications of guanidines, see: Han et al. (2008 ▶); Hannon & Anslyn (1993 ▶); Ekelund et al. (2001 ▶); Kovacevic & Maksic (2001 ▶); Costa et al. (1998 ▶). For graph-set motifs, see: Bernstein et al. (1995 ▶) and for standard bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₈H₁₀N₅ ⁺·C₇H₇O₃S⁻
M _r = 347.41
Monoclinic,
a = 12.3821 (4) Å
b = 17.8077 (7) Å
c = 14.5112 (5) Å
β = 90.013 (2)°
V = 3199.7 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 100 K
0.35 × 0.10 × 0.04 mm

Data collection

Bruker APEXII CCD diffractometer
20618 measured reflections
5679 independent reflections
4108 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.109
S = 1.05
5679 reflections
469 parameters
15 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Data collection: APEX2 (Bruker, 2013 ▶); cell refinement: SAINT (Bruker, 2013 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813024975/sj5349sup1.cif

e-69-o1543-sup1.cif^{(39.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813024975/sj5349Isup2.hkl

e-69-o1543-Isup2.hkl^{(311.3KB, hkl)}

Click here for additional data file.^{(6.4KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813024975/sj5349Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—HN1⋯O1ⁱ	0.86 (2)	2.11 (2)	2.948 (3)	166 (2)
N3—HN3⋯O6ⁱⁱ	0.86 (2)	1.95 (2)	2.805 (3)	173 (2)
N6—HN6⋯O6ⁱⁱⁱ	0.88 (2)	2.09 (2)	2.944 (3)	164 (2)
N8—HN8⋯O1^iv	0.87 (2)	1.93 (2)	2.799 (2)	177 (2)
N4—H4A⋯N2	0.87 (2)	1.97 (2)	2.686 (3)	139 (2)
N4—H4B⋯O3	0.87 (2)	2.06 (2)	2.909 (3)	166 (2)
N5—H5A⋯O5ⁱⁱ	0.89 (2)	1.98 (2)	2.871 (3)	176 (3)
N5—H5B⋯O2	0.88 (2)	1.99 (2)	2.863 (3)	169 (3)
N9—H9A⋯N7	0.86 (2)	1.98 (2)	2.683 (3)	138 (2)
N9—H9B⋯O5^v	0.85 (2)	2.06 (2)	2.906 (3)	174 (2)
N10—H10A⋯O4^v	0.88 (2)	2.00 (2)	2.863 (3)	167 (3)
N10—H10B⋯O3^iv	0.89 (2)	1.99 (2)	2.872 (3)	179 (3)
C7—H7C⋯O4^vi	0.98	2.53	3.283 (3)	133

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

Manchester Metropolitan University, Erciyes University and Sohag University are gratefully acknowledged for supporting this study. The authors also thank José Romero Garzón, Centro de Instrumentación Científica, Universidad de Granada, for the data collection.

supplementary crystallographic information

1. Comment

Guanidines are structurally novel molecules reported to exhibit remarkable biological and pharmacological activities, which are affected by the guanidine functionality (Han et al., 2008; Hannon & Anslyn, 1993). Guanidino-containing drugs such as metaiodobenzylguanidine, MIBG, and methylglyoxalbisguanylhydrazone, MGBG, were shown several decades ago to have antitumor properties and have been subjected to intense preclinical and clinical evaluation (Ekelund et al., 2001). Guanidines are also known as useful basic catalysts (Kovacevic & Maksic, 2001; Costa et al., 1998). The synthesis of guanidine derivatives has also attracted continued research interests in recent years, resulting in many new efficient synthetic methods and guanidinylation reagents for different classes of guanidine compounds (Wu et al., 2002; Hopkins et al., 2002; Kilburn et al., 2002; Manimala & Anslyn, 2002). Against this background, we report herein the the synthesis and crystal structure of the title compound.

As seen as in Fig. 1, the asymmetric unit contains two amino(1H-benzimidazol-2-ylamino)methaniminium) cations and two 4-methylbenzenesulfonate anions. The bond lengths in the title compound are within the normal range (Allen et al., 1987).

In the cations, intramolecular N4—H4A···N2 and N9—H9A···N7 hydrogen bonds generate six-membered S(6) rings in each cation (Bernstein et al., 1995). In the crystal, a three-dimensional supramolecular framework is formed via intermolecular N—H···O and C—H···O hydrogen bonds between the cations and anions (Table 1, Fig. 2). Furthermore, two strong π-π stacking interactions [Cg1···Cg1 (-x, 1 - y, -z) = 3.4112 (14) Å and Cg4···Cg4 (1 - x, 1 - y, 2 - z) = 3.4104 (14) Å] also occur between the imidazole rings of like cations (Cg1 and Cg4 are the centroids of the N1/C8/C13/N2/C14 and N6/C23/C28/N7/C29 ring respectively).

2. Experimental

A mixture of 175 mg (1 mmol) 1-(1H-benzimidazol-2-yl)guanidine and 191 mg (1 mmol) of 4-methylbenzenesulfonyl chloride was heated under reflux in 50 ml ethanol together with few drops of triethylamine for 6 h. The solid product started to be deposited during heating and filtered off after completion. The crude solid was washed with ethanol and recrystallized to afford colourless plates suitable for X-ray difraction (M.p. 539–541 K).