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Crystal structure of bis­­[2-(1H-benzimidazol-2-yl)aniline]silver(I) nitrate

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aDepartment of Chemistry, Chungnam National University, Daejeon 305-764, Republic of Korea
*Correspondence e-mail: skkang@cnu.ac.kr

Edited by H. Ishida, Okayama University, Japan (Received 6 August 2015; accepted 17 August 2015; online 22 August 2015)

In the cation of the title salt, [Ag(C13H11N3)2]NO3, the AgI atom lies on a crystallographic inversion center and is coordinated by four N atoms from two bidentate 2-(1H-benzimidazol-2-yl)aniline ligands in a distorted square-planar geometry. The Ag—N(aniline) bond [2.729 (2) Å] is significantly longer than the Ag—N(imidazole) bond [2.165 (1) Å]. In the ligand, the aniline ring is twisted by 37.87 (6)° from the mean plane of the benzimidazole ring system. The nitrate anion lies on a crystallographic twofold rotation axis which passes through the N atom and one of the O atoms. In the crystal, N—H⋯O hydrogen bonds link the components, forming a layer parallel to the bc plane.

1. Chemical context

Azole and benzazole derivatives have been of inter­est in an important group in biological systems (Esparza-Ruiz et al., 2011[Esparza-Ruiz, A., Peña-Hueso, A., Mijangos, E., Osorio-Monreal, G., Nöth, H., Flores-Parra, A., Contreras, R. & Barba-Behrens, N. (2011). Polyhedron, 30, 2090-2098.]; Hock et al., 2013[Hock, S. J., Schaper, L., Herrmann, W. A. & Kühn, F. E. (2013). Chem. Soc. Rev. 42, 5073-5089.]). Benzimidazoles have shown anti­viral and anti­tumor activity (Wang et al., 2007[Wang, X. A., Cianci, C. W., Yu, K.-L., Combrink, K. D., Thuring, J. W., Zhang, Y., Civiello, R. L., Kadow, K. F., Roach, J., Li, Z., Langley, D. R., Krystal, M. & Meanwell, N. A. (2007). Bioorg. Med. Chem. Lett. 17, 4592-4598.]; Ramla et al., 2007[Ramla, M. M., Omar, M. A., Tokuda, H. & El-Diwani, H. I. (2007). Bioorg. Med. Chem. 15, 6489-6496.]). Some transition metal complexes with benzimidazole derivatives are important biological mol­ecules (Sánchez-Guadarrama et al., 2009[Sánchez-Guadarrama, O., López-Sandoval, H., Sánchez-Bartéz, F., Gracia-Mora, I., Höpfl, H. & Barba-Behrens, N. (2009). J. Inorg. Biochem. 103, 1204-1213.]; Gökçe et al., 2005[Gökçe, M., Utku, S., Gür, S., Özkul, A. & Gümüş, F. (2005). Eur. J. Med. Chem. 40, 135-141.]). The complexes of silver(I) with a series of benzimidazole-based N-heterocyclic carbenes have shown in vitro anti­bacterial potential against E. coli and B. subtilis bacteria (Haque et al., 2015[Haque, R. A., Choo, S. Y., Budagumpi, S., Iqbal, M. A. & Al-Ashraf Abdullah, A. (2015). Eur. J. Med. Chem. 90, 82-92.]). Recently, we reported on the synthesis and structural features of a zinc complex with a benzimidazole derivative (Kim & Kang, 2015[Kim, Y. & Kang, S. K. (2015). Acta Cryst. E71, m85-m86.]). In a continuation of our research in this area, the title complex has been synthesized and characterized by single crystal diffraction.

[Scheme 1]

2. Structural commentary

The cationic AgI complex adopts a distorted square-planar geometry with four N atoms of two bidentate 2-(1H-benzimidazol-2-yl)aniline ligands (Fig. 1[link]). The AgI atom lies on a crystallographic inversion center. The smaller N2—Ag1—N17 angle is 74.8 (1)° and the other is 105.2 (1)°. The benzimidazole ring system (N2–C10) is almost planar with an r.m.s. deviation of 0.015 (2) Å from the corresponding least-squares plane defined by the nine constituent atoms. The dihedral angle between the benzimidazole ring system and the aniline ring is 37.87 (6)°. This twisting is a driving force in the formation of the weak Ag1—N17 bonding in the Ag complex. The Ag1—N17 bond length of 2.729 (2) Å is much longer than the Ag1—N2 bond length of 2.165 (1) Å. Typical Ag—N bond lengths are within the range 2.1–2.4 Å (Gulbransen & Fitchett, 2012[Gulbransen, J. L. & Fitchett, C. M. (2012). CrystEngComm, 14, 5394-5397.]; Pettinari et al., 2013[Pettinari, C., Marchetti, F., Orbisaglia, S., Pettinari, R., Ngoune, J., Gómez, M., Santos, C. & Álvarez, E. (2013). CrystEngComm, 15, 3892-3907.]; Sun et al., 2006[Sun, Q., Bai, Y., He, G., Duan, C., Lin, Z. & Meng, Q. (2006). Chem. Commun. pp. 2777-2779.]). However, the bond length of 2.729 (2) Å is shorter than the sum of the van der Waals radii of N and Ag atoms (1.55 and 1.70 Å, respectively; Bondi, 1964[Bondi, A. (1964). J. Phys. Chem. 68, 441-451.]). In the heterocyclic imidazole ring, the N2—C10 bond [1.331 (2) Å] is shorter than the other N—C bonds [N2—C3 1.388 (2), C8—N9 1.380 (2), N9—C10 1.352 Å], which means the N2—C10 bond has double-bond character. In the nitrate counter-anion, atoms N18 and O20 lie on a crystallographic twofold rotation axis.

[Figure 1]
Figure 1
Mol­ecular structure of the title compound, showing the atom-numbering scheme and 30% probability ellipsoids. The N—H⋯O hydrogen bond is indicated by a dashed line. [Symmetry codes: (i) −x, −y, −z + 1; (ii) −x, y, −z + [{1\over 2}].]

3. Supra­molecular features

In the crystal, the N—H group of the 2-(1H-benzimidazol-2-yl)aniline ligand inter­acts strongly with the counter-anion, giving rise to a nearly linear hydrogen bond (Table 1[link]), which forms a zigzag chain along the c axis (Fig. 2[link]). Another weak N—H⋯O hydrogen bond between the NH2 group and the anion (Table 1[link]) links the chains into a layer parallel to the bc plane.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N9—H9⋯O20 0.81 (3) 2.05 (3) 2.8588 (18) 178 (3)
N17—H17B⋯O19i 0.89 (3) 2.35 (3) 3.214 (2) 164 (2)
Symmetry code: (i) [-x, y-1, -z+{\script{1\over 2}}].
[Figure 2]
Figure 2
Part of the crystal structure of the title compound, showing mol­ecules linked by inter­molecular N—H⋯O hydrogen bonds (dashed lines).

4. Database survey

A search of the Cambridge Structural Database (Version 5.36 with one update; Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]) returned 2993 entries for crystal structures of benzimidazoles. Most of them are crystal structures of metal complexes. However, there are only four entries with the ligand 2-(1H-benzimidazol-2-yl)aniline or 2-(2-amino­phen­yl)-1H-benzimidazole bonded to a transition metal: a Zn complex (Eltayeb et al., 2011[Eltayeb, N. E., Teoh, S. G., Chantrapromma, S. & Fun, H.-K. (2011). Acta Cryst. E67, m1062-m1063.]), an Ni (Esparza-Ruiz et al., 2011[Esparza-Ruiz, A., Peña-Hueso, A., Mijangos, E., Osorio-Monreal, G., Nöth, H., Flores-Parra, A., Contreras, R. & Barba-Behrens, N. (2011). Polyhedron, 30, 2090-2098.]), an Re (Machura et al., 2011[Machura, B., Wolff, M., Gryca, I., Palion, A. & Michalik, K. (2011). Polyhedron, 30, 2275-2285.]) and an Ru (Malecki, 2012[Małecki, J. G. (2012). Struct. Chem. 23, 461-472.]).

5. Synthesis and crystallization

To a stirred solution of Ag(NO3) (0.085 g, 0.5 mmol) in aceto­nitrile (5 ml) was added a solution of 2-(1H-benzimidazol-2-yl)aniline (0.211 g, 1.0 mmol) in aceto­nitrile (10 ml) at 333 K. After 24 h of stirring, the solution turned ivory in color. Single crystals of the title complex were obtained by slow evaporation of the solvent at room temperature within three weeks.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. H atoms of the NH and NH2 groups were located in a difference Fourier map and refined freely [refined distances; N—H = 0.81 (3)–0.89 (3) Å]. Other H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93 Å, and with Uiso(H) = 1.2Ueq(C).

Table 2
Experimental details

Crystal data
Chemical formula [Ag(C13H11N3)2]NO3
Mr 588.37
Crystal system, space group Orthorhombic, Pbcn
Temperature (K) 296
a, b, c (Å) 11.9903 (2), 10.1377 (2), 20.1115 (5)
V3) 2444.63 (9)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.87
Crystal size (mm) 0.18 × 0.16 × 0.15
 
Data collection
Diffractometer Bruker SMART CCD area detector
Absorption correction Multi-scan (SADABS; Bruker, 2002[Bruker (2002). SADABS, SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.846, 0.872
No. of measured, independent and observed [I > 2σ(I)] reflections 62591, 3043, 2446
Rint 0.034
(sin θ/λ)max−1) 0.667
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.030, 0.080, 1.06
No. of reflections 3043
No. of parameters 182
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.44, −0.48
Computer programs: SMART and SAINT (Bruker, 2002[Bruker (2002). SADABS, SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXS2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2013 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis[2-(1H-benzimidazol-2-yl)aniline]silver(I) nitrate top
Crystal data top
[Ag(C13H11N3)2](NO3)Dx = 1.599 Mg m3
Mr = 588.37Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbcnCell parameters from 9923 reflections
a = 11.9903 (2) Åθ = 2.6–28.3°
b = 10.1377 (2) ŵ = 0.87 mm1
c = 20.1115 (5) ÅT = 296 K
V = 2444.63 (9) Å3Block, colourless
Z = 40.18 × 0.16 × 0.15 mm
F(000) = 1192
Data collection top
Bruker SMART CCD area-detector
diffractometer
2446 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.034
φ and ω scansθmax = 28.3°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2002)
h = 1515
Tmin = 0.846, Tmax = 0.872k = 1313
62591 measured reflectionsl = 2626
3043 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.030H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.080 w = 1/[σ2(Fo2) + (0.0371P)2 + 1.1132P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
3043 reflectionsΔρmax = 0.44 e Å3
182 parametersΔρmin = 0.48 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ag10.00000.00000.50000.04858 (10)
N20.04065 (13)0.18355 (14)0.45056 (7)0.0336 (3)
C30.09293 (15)0.29248 (18)0.47845 (9)0.0340 (4)
C40.13679 (17)0.3119 (2)0.54221 (10)0.0436 (4)
H40.13560.24500.57390.052*
C50.18161 (19)0.4335 (2)0.55614 (11)0.0527 (5)
H50.21190.44870.59800.063*
C60.1829 (2)0.5349 (3)0.50918 (12)0.0588 (6)
H60.21330.61610.52080.071*
C70.14013 (19)0.5180 (2)0.44611 (12)0.0512 (5)
H70.14170.58520.41460.061*
C80.09453 (15)0.39484 (18)0.43215 (9)0.0365 (4)
N90.04206 (14)0.34549 (15)0.37641 (8)0.0355 (3)
H90.030 (2)0.381 (3)0.3412 (13)0.056 (7)*
C100.01033 (14)0.22026 (16)0.38965 (8)0.0300 (3)
C110.05731 (14)0.14278 (16)0.34296 (8)0.0295 (3)
C120.13818 (14)0.20841 (18)0.30566 (9)0.0364 (4)
H120.14480.29950.30950.044*
C130.20848 (15)0.1415 (2)0.26327 (9)0.0405 (4)
H130.26050.18710.23780.049*
C140.20058 (17)0.00563 (19)0.25906 (9)0.0407 (4)
H140.24970.04090.23200.049*
C150.12026 (16)0.06123 (18)0.29469 (9)0.0386 (4)
H150.11550.15250.29110.046*
C160.04616 (16)0.00555 (16)0.33594 (9)0.0320 (4)
N170.03508 (17)0.06622 (18)0.37016 (8)0.0410 (4)
H17A0.092 (2)0.021 (2)0.3769 (11)0.042 (6)*
H17B0.048 (2)0.145 (3)0.3528 (13)0.068 (8)*
N180.00000.5893 (2)0.25000.0314 (4)
O190.02905 (14)0.64820 (15)0.19918 (8)0.0534 (4)
O200.00000.4645 (2)0.25000.0446 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ag10.07365 (18)0.03391 (13)0.03818 (13)0.00637 (10)0.00441 (10)0.01569 (8)
N20.0448 (8)0.0272 (7)0.0287 (7)0.0002 (6)0.0025 (6)0.0041 (6)
C30.0372 (9)0.0314 (9)0.0332 (8)0.0026 (7)0.0043 (7)0.0015 (7)
C40.0487 (10)0.0466 (11)0.0355 (9)0.0064 (9)0.0113 (8)0.0006 (8)
C50.0548 (12)0.0550 (13)0.0483 (12)0.0016 (10)0.0205 (10)0.0094 (10)
C60.0637 (15)0.0460 (12)0.0666 (15)0.0147 (11)0.0202 (11)0.0103 (11)
C70.0612 (13)0.0357 (11)0.0565 (13)0.0134 (9)0.0141 (11)0.0052 (9)
C80.0413 (10)0.0312 (9)0.0369 (9)0.0029 (7)0.0066 (7)0.0026 (7)
N90.0483 (8)0.0268 (8)0.0315 (8)0.0070 (6)0.0069 (7)0.0071 (6)
C100.0359 (8)0.0250 (8)0.0291 (8)0.0005 (6)0.0001 (6)0.0034 (6)
C110.0344 (8)0.0267 (8)0.0273 (8)0.0027 (7)0.0026 (6)0.0022 (6)
C120.0386 (9)0.0290 (8)0.0415 (10)0.0005 (7)0.0013 (7)0.0020 (7)
C130.0335 (9)0.0455 (11)0.0427 (10)0.0002 (8)0.0043 (7)0.0007 (8)
C140.0381 (9)0.0439 (11)0.0402 (11)0.0089 (8)0.0035 (7)0.0098 (8)
C150.0467 (10)0.0280 (9)0.0411 (10)0.0051 (8)0.0075 (8)0.0072 (7)
C160.0386 (8)0.0298 (9)0.0278 (8)0.0011 (7)0.0074 (7)0.0013 (6)
N170.0558 (10)0.0306 (9)0.0366 (9)0.0083 (8)0.0003 (8)0.0004 (7)
N180.0370 (10)0.0232 (10)0.0341 (10)0.0000.0049 (9)0.000
O190.0731 (10)0.0381 (8)0.0491 (8)0.0022 (7)0.0064 (7)0.0155 (7)
O200.0759 (14)0.0209 (8)0.0368 (10)0.0000.0055 (9)0.000
Geometric parameters (Å, º) top
Ag1—N2i2.1653 (14)C10—C111.468 (2)
Ag1—N22.1653 (14)C11—C121.395 (2)
Ag1—N172.7288 (17)C11—C161.405 (2)
N2—C101.331 (2)C12—C131.377 (3)
N2—C31.388 (2)C12—H120.9300
C3—C81.394 (2)C13—C141.383 (3)
C3—C41.400 (2)C13—H130.9300
C4—C51.374 (3)C14—C151.379 (3)
C4—H40.9300C14—H140.9300
C5—C61.396 (3)C15—C161.391 (3)
C5—H50.9300C15—H150.9300
C6—C71.379 (3)C16—N171.397 (3)
C6—H60.9300N17—H17A0.83 (2)
C7—C81.392 (3)N17—H17B0.89 (3)
C7—H70.9300N18—O19ii1.2340 (17)
C8—N91.380 (2)N18—O191.2340 (17)
N9—C101.352 (2)N18—O201.265 (3)
N9—H90.81 (3)
N2i—Ag1—N2180.0N9—C10—C11122.12 (15)
N2i—Ag1—N17105.23 (6)C12—C11—C16118.98 (16)
N2—Ag1—N1774.77 (5)C12—C11—C10118.21 (15)
C10—N2—C3105.83 (14)C16—C11—C10122.78 (16)
C10—N2—Ag1126.97 (12)C13—C12—C11121.57 (17)
C3—N2—Ag1126.86 (11)C13—C12—H12119.2
N2—C3—C8109.18 (15)C11—C12—H12119.2
N2—C3—C4130.65 (17)C12—C13—C14119.08 (18)
C8—C3—C4120.14 (17)C12—C13—H13120.5
C5—C4—C3117.37 (19)C14—C13—H13120.5
C5—C4—H4121.3C15—C14—C13120.38 (18)
C3—C4—H4121.3C15—C14—H14119.8
C4—C5—C6121.8 (2)C13—C14—H14119.8
C4—C5—H5119.1C14—C15—C16121.11 (17)
C6—C5—H5119.1C14—C15—H15119.4
C7—C6—C5121.8 (2)C16—C15—H15119.4
C7—C6—H6119.1C15—C16—N17119.05 (17)
C5—C6—H6119.1C15—C16—C11118.75 (17)
C6—C7—C8116.3 (2)N17—C16—C11122.18 (17)
C6—C7—H7121.8C16—N17—Ag1103.64 (11)
C8—C7—H7121.8C16—N17—H17A111.8 (15)
N9—C8—C7131.96 (17)Ag1—N17—H17A80.7 (16)
N9—C8—C3105.46 (15)C16—N17—H17B113.6 (17)
C7—C8—C3122.57 (18)Ag1—N17—H17B128.7 (17)
C10—N9—C8107.99 (15)H17A—N17—H17B114 (2)
C10—N9—H9122.6 (19)O19ii—N18—O19122.1 (2)
C8—N9—H9129.4 (19)O19ii—N18—O20118.96 (11)
N2—C10—N9111.53 (15)O19—N18—O20118.96 (11)
N2—C10—C11126.15 (15)
Symmetry codes: (i) x, y, z+1; (ii) x, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N9—H9···O200.81 (3)2.05 (3)2.8588 (18)178 (3)
N17—H17B···O19iii0.89 (3)2.35 (3)3.214 (2)164 (2)
Symmetry code: (iii) x, y1, z+1/2.
 

Acknowledgements

This work was supported by the research fund of Chungnam National University.

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