research communications
H-benzimidazol-2-yl-κN3)aniline-κN]bis(nitrato-κO)cadmium(II)
of bis[2-(1aDepartment of Chemistry, Chungnam National University, Daejeon 305-764, Republic of Korea
*Correspondence e-mail: skkang@cnu.ac.kr
In the title compound, [Cd(NO3)2(C13H11N3)2], the CdII atom lies on a twofold rotation axis and is coordinated by four N atoms and two O atoms, provided by two bidentate 2-(1H-benzimidazol-2-yl)aniline ligands, and two nitrato O atoms, forming a distorted octahedral geometry [range of bond angles around the Cd atom = 73.82 (2)–106.95 (8)°]. In the ligand, the dihedral angle between the aniline ring and the benzimidazole ring system is 30.43 (7)°. The discrete complex molecule is stabilized by an intramolecular N—H⋯O hydrogen bond. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules, forming a three-dimensional network.
CCDC reference: 1951821
1. Chemical context
Azole and benzazole derivatives are well-known nitrogen-containing et al., 2011; Hock et al., 2013). Imidazole is an azapyrrole in which the nitrogen atoms are separated by one carbon atom. Benzimidazole, a fused heterocycle with benzene and imidazole, is associated with a wide array of pharmacological activities (Akhtar et al., 2017), and benzimidazole derivatives exhibit a wide range of various biological activities. These include bactericidal (Carcanague et al., 2002) and fungicidal (Lezcano et al., 2002; Aghatabay et al., 2007) properties. Their metal complexes have been shown to display antitumor activity and are important biological molecules (Sánchez-Guadarrama et al., 2009; Ramla et al., 2007; Wang et al., 2007). Recently, we reported on the synthesis and structural features of Zn (Kim & Kang, 2015a) and Ag (Kim & Kang, 2015b) complexes with benzimidazole derivatives. In this work, we have synthesized the title compound and characterized it by single crystal X-ray crystallography.
and are of great interest because of their broad spectrum of biological activity (Esparza-Ruiz2. Structural commentary
The molecular structure of the title complex is shown in Fig. 1. The complex lies about a twofold rotation axis which passes through the CdII atom, the coordination geometry around which is distorted octahedral with two O atoms of two nitrato ligands and four N atoms of two bidentate 2-(1H-benzimidazol-2-yl)aniline ligands. The Cd—N and Cd—O bond lengths [Cd1—N2 = 2.317 (2), Cd1—N17 = 2.437 (2) and Cd1—O19 = 2.3175 (19) Å] are comparable with those of other Cd complexes (Barszcz et al., 2013; Jalilehvand et al., 2009). The bond angles around the Cd1 atom are in the range of 73.82 (8)–106.95 (8)°. The dihedral angle between the benzimidazole (N2/C3–C8/N9/C10) ring system and the aniline (C11–C16/N17) plane in the bidentate ligand is 30.43 (7)°. This twisting is a driving force in the formation of weak Cd1—N17 bonding, this bond being [2.437 (2) Å] a little longer than Cd1—N2 [2.317 (2) Å]. This elongation was also observed in our previous studies of imidazoleaniline–metal complexes (Zn: Kim & Kang, 2015a; Ag: Kim & Kang, 2015b). The N2—C10 bond length of 1.327 (3) Å in the imidazole ring shows double-bond character compared to the other N—C bond lengths [N2—C3 = 1.397 (3), C8—N9 = 1.384 (3) and N9—C10 = 1.355 (3) Å]. The discrete molecule is stabilized by an intramolecular N—H⋯O hydrogen bond (Table 1).
3. Supramolecular features
In the crystal, molecules are linked by a series of N—H⋯O interactions. The nitrate group containing oxygen atom O21 forms both intra- and intermolecular hydrogen bonds. Molecules are arranged into a zigzag chain along the c-axis direction via an N—H⋯O hydrogen bond (N17—H17B⋯O20ii; symmetry code as in Table 1; Fig. 2). The other N—H⋯O hydrogen bonds (N9—H9⋯O20i and N9—H9⋯O21i; Table 1) link the molecules into a three-dimensional network (Fig. 3).
4. Database survey
A search of the Cambridge Structural Database (CSD, Version 5.40, Feb. 2019; Groom et al., 2016) gave 4678 entries for crystal structures related to benzimidazoles. However, there are only 14 entries involving the ligands 2-(1H-benzimidazol-2-yl)aniline or 2-(2-aminophenyl)-1H-benzimidazole with a transition metal. These include Ni (refcode EWUZOM; Esparza-Ruiz et al., 2011), Zn [AWOLEE (Eltayeb et al., 2011) and JUFCOE (Kim & Kang, 2015a)], Ru (NUNLID; Małecki, 2012) and Re (UYELEQ; Machura et al., 2011).
5. Synthesis and crystallization
Chemicals were obtained commercially in reagent grade and used as received. Solvents were dried using standard procedures described in the literature. To a stirred solution of Cd(NO3)·4H2O (0.154 g, 0.5 mmol) in ethanol (20 ml) was added a solution of 2-(1H-benzimidazol-2-yl)aniline (0.209 g, 1.0 mmol) in ethanol (10 ml) at 333 K. After 24 h of stirring, the title complex was obtained as a white powder. The powder was filtered off and washed with ethanol. Colourless crystals of the title complex were obtained by slow evaporation of the methanol solvent at room temperature within two weeks.
6. Refinement
Crystal data, data collection and structure . H atoms of the NH and NH2 groups were located in a difference-Fourier map and refined freely [refined distances: N—H = 0.75 (3)–0.86 (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).
details are summarized in Table 2Supporting information
CCDC reference: 1951821
https://doi.org/10.1107/S2056989019012416/is5523sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989019012416/is5523Isup2.hkl
Data collection: SMART (Bruker, 2012); cell
SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); 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: WinGX (Farrugia, 2012).[Cd(NO3)2(C13H11N3)2] | F(000) = 1320 |
Mr = 654.91 | Dx = 1.684 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 14.6899 (4) Å | Cell parameters from 5554 reflections |
b = 15.0250 (3) Å | θ = 2.4–28.0° |
c = 12.2269 (3) Å | µ = 0.91 mm−1 |
β = 106.8431 (15)° | T = 296 K |
V = 2582.90 (11) Å3 | Block, colourless |
Z = 4 | 0.15 × 0.13 × 0.12 mm |
Bruker SMART CCD area-detector diffractometer | 2729 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.031 |
φ and ω scans | θmax = 28.3°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Bruker, 2012) | h = −19→17 |
Tmin = 0.546, Tmax = 0.726 | k = −19→20 |
11727 measured reflections | l = −16→16 |
3087 independent reflections |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.035 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.078 | w = 1/[σ2(Fo2) + (0.0422P)2 + 0.8298P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
3087 reflections | Δρmax = 0.82 e Å−3 |
198 parameters | Δρmin = −0.35 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
Cd1 | 0.5000 | 0.62214 (2) | 0.7500 | 0.03198 (10) | |
N2 | 0.59443 (14) | 0.72062 (13) | 0.68561 (17) | 0.0345 (4) | |
C3 | 0.60535 (16) | 0.72958 (16) | 0.5763 (2) | 0.0357 (5) | |
C4 | 0.57954 (19) | 0.6718 (2) | 0.4835 (2) | 0.0470 (7) | |
H4 | 0.5507 | 0.6173 | 0.4877 | 0.056* | |
C5 | 0.5990 (2) | 0.6994 (2) | 0.3847 (3) | 0.0562 (8) | |
H5 | 0.5826 | 0.6628 | 0.3206 | 0.067* | |
C6 | 0.6425 (2) | 0.7807 (2) | 0.3793 (3) | 0.0594 (8) | |
H6 | 0.6538 | 0.7970 | 0.3110 | 0.071* | |
C7 | 0.6695 (2) | 0.8379 (2) | 0.4705 (3) | 0.0495 (7) | |
H7 | 0.6997 | 0.8917 | 0.4663 | 0.059* | |
C8 | 0.64909 (17) | 0.81075 (17) | 0.5695 (2) | 0.0373 (5) | |
N9 | 0.66350 (16) | 0.85021 (15) | 0.67542 (19) | 0.0380 (5) | |
H9 | 0.696 (2) | 0.889 (2) | 0.697 (3) | 0.054 (10)* | |
C10 | 0.62989 (16) | 0.79434 (15) | 0.7417 (2) | 0.0323 (5) | |
C11 | 0.62624 (16) | 0.81778 (15) | 0.8566 (2) | 0.0334 (5) | |
C12 | 0.6159 (2) | 0.90724 (18) | 0.8829 (2) | 0.0443 (6) | |
H12 | 0.6155 | 0.9506 | 0.8285 | 0.053* | |
C13 | 0.6065 (2) | 0.93253 (19) | 0.9865 (3) | 0.0540 (7) | |
H13 | 0.5984 | 0.9922 | 1.0017 | 0.065* | |
C14 | 0.6090 (2) | 0.86845 (19) | 1.0683 (3) | 0.0520 (7) | |
H14 | 0.6028 | 0.8852 | 1.1390 | 0.062* | |
C15 | 0.62043 (18) | 0.78054 (18) | 1.0463 (2) | 0.0428 (6) | |
H15 | 0.6230 | 0.7383 | 1.1027 | 0.051* | |
C16 | 0.62832 (16) | 0.75354 (16) | 0.9400 (2) | 0.0331 (5) | |
N17 | 0.63122 (16) | 0.66172 (14) | 0.9164 (2) | 0.0367 (5) | |
H17A | 0.674 (2) | 0.6453 (18) | 0.885 (3) | 0.040 (8)* | |
H17B | 0.640 (2) | 0.6314 (18) | 0.972 (3) | 0.037 (8)* | |
N18 | 0.63805 (17) | 0.48486 (14) | 0.6968 (2) | 0.0457 (5) | |
O19 | 0.55302 (15) | 0.50697 (13) | 0.6581 (2) | 0.0584 (6) | |
O20 | 0.67211 (17) | 0.43131 (17) | 0.6449 (2) | 0.0793 (8) | |
O21 | 0.6875 (2) | 0.51407 (17) | 0.7877 (2) | 0.0861 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd1 | 0.02785 (14) | 0.02431 (13) | 0.04112 (16) | 0.000 | 0.00582 (10) | 0.000 |
N2 | 0.0292 (11) | 0.0388 (11) | 0.0348 (11) | −0.0043 (8) | 0.0083 (8) | −0.0076 (9) |
C3 | 0.0269 (12) | 0.0433 (14) | 0.0362 (14) | 0.0012 (9) | 0.0078 (10) | −0.0038 (11) |
C4 | 0.0370 (15) | 0.0591 (18) | 0.0432 (16) | −0.0004 (12) | 0.0090 (11) | −0.0138 (13) |
C5 | 0.0521 (18) | 0.076 (2) | 0.0366 (16) | 0.0124 (15) | 0.0060 (13) | −0.0119 (15) |
C6 | 0.066 (2) | 0.079 (2) | 0.0350 (16) | 0.0263 (17) | 0.0172 (14) | 0.0110 (16) |
C7 | 0.0522 (18) | 0.0522 (17) | 0.0479 (17) | 0.0117 (13) | 0.0205 (13) | 0.0133 (14) |
C8 | 0.0321 (13) | 0.0434 (14) | 0.0361 (14) | 0.0049 (10) | 0.0092 (10) | 0.0016 (11) |
N9 | 0.0379 (12) | 0.0354 (11) | 0.0402 (12) | −0.0066 (9) | 0.0107 (9) | −0.0014 (10) |
C10 | 0.0267 (12) | 0.0323 (12) | 0.0351 (13) | −0.0033 (9) | 0.0046 (9) | −0.0005 (10) |
C11 | 0.0320 (13) | 0.0318 (12) | 0.0355 (13) | −0.0066 (9) | 0.0084 (10) | −0.0045 (10) |
C12 | 0.0547 (17) | 0.0322 (12) | 0.0476 (16) | −0.0077 (11) | 0.0175 (13) | −0.0027 (12) |
C13 | 0.070 (2) | 0.0368 (15) | 0.0595 (19) | −0.0068 (13) | 0.0257 (16) | −0.0164 (14) |
C14 | 0.066 (2) | 0.0513 (17) | 0.0434 (16) | −0.0139 (14) | 0.0238 (14) | −0.0129 (13) |
C15 | 0.0465 (16) | 0.0441 (15) | 0.0365 (15) | −0.0082 (11) | 0.0097 (11) | −0.0019 (11) |
C16 | 0.0265 (12) | 0.0341 (12) | 0.0357 (13) | −0.0047 (9) | 0.0042 (9) | −0.0031 (10) |
N17 | 0.0372 (13) | 0.0329 (11) | 0.0374 (13) | 0.0007 (9) | 0.0068 (10) | 0.0019 (10) |
N18 | 0.0556 (15) | 0.0329 (11) | 0.0444 (14) | 0.0093 (10) | 0.0079 (11) | −0.0038 (10) |
O19 | 0.0457 (12) | 0.0411 (11) | 0.0832 (16) | 0.0077 (8) | 0.0105 (11) | −0.0139 (10) |
O20 | 0.0740 (16) | 0.0897 (19) | 0.0650 (15) | 0.0407 (14) | 0.0059 (12) | −0.0261 (14) |
O21 | 0.099 (2) | 0.0681 (16) | 0.0665 (17) | 0.0171 (14) | −0.0153 (14) | −0.0294 (13) |
Cd1—N2 | 2.317 (2) | N9—C10 | 1.355 (3) |
Cd1—N2i | 2.317 (2) | N9—H9 | 0.75 (3) |
Cd1—O19 | 2.3175 (19) | C10—C11 | 1.464 (3) |
Cd1—O19i | 2.3175 (19) | C11—C16 | 1.398 (3) |
Cd1—N17 | 2.437 (2) | C11—C12 | 1.401 (3) |
Cd1—N17i | 2.437 (2) | C12—C13 | 1.368 (4) |
N2—C10 | 1.327 (3) | C12—H12 | 0.9300 |
N2—C3 | 1.397 (3) | C13—C14 | 1.381 (4) |
C3—C4 | 1.392 (4) | C13—H13 | 0.9300 |
C3—C8 | 1.392 (3) | C14—C15 | 1.368 (4) |
C4—C5 | 1.384 (4) | C14—H14 | 0.9300 |
C4—H4 | 0.9300 | C15—C16 | 1.398 (4) |
C5—C6 | 1.389 (5) | C15—H15 | 0.9300 |
C5—H5 | 0.9300 | C16—N17 | 1.413 (3) |
C6—C7 | 1.373 (4) | N17—H17A | 0.86 (3) |
C6—H6 | 0.9300 | N17—H17B | 0.79 (3) |
C7—C8 | 1.390 (4) | N18—O20 | 1.218 (3) |
C7—H7 | 0.9300 | N18—O21 | 1.219 (3) |
C8—N9 | 1.384 (3) | N18—O19 | 1.246 (3) |
N2—Cd1—N2i | 100.60 (10) | C7—C8—C3 | 122.0 (3) |
N2—Cd1—O19 | 89.64 (8) | C10—N9—C8 | 108.1 (2) |
N2i—Cd1—O19 | 163.78 (7) | C10—N9—H9 | 125 (3) |
N2—Cd1—O19i | 163.78 (7) | C8—N9—H9 | 125 (3) |
N2i—Cd1—O19i | 89.64 (8) | N2—C10—N9 | 111.4 (2) |
O19—Cd1—O19i | 83.39 (11) | N2—C10—C11 | 125.3 (2) |
N2—Cd1—N17 | 73.82 (8) | N9—C10—C11 | 123.1 (2) |
N2i—Cd1—N17 | 88.10 (7) | C16—C11—C12 | 118.4 (2) |
O19—Cd1—N17 | 106.95 (8) | C16—C11—C10 | 122.3 (2) |
O19i—Cd1—N17 | 94.19 (8) | C12—C11—C10 | 119.2 (2) |
N2—Cd1—N17i | 88.10 (7) | C13—C12—C11 | 121.8 (3) |
N2i—Cd1—N17i | 73.82 (8) | C13—C12—H12 | 119.1 |
O19—Cd1—N17i | 94.18 (8) | C11—C12—H12 | 119.1 |
O19i—Cd1—N17i | 106.95 (8) | C12—C13—C14 | 119.2 (3) |
N17—Cd1—N17i | 151.75 (10) | C12—C13—H13 | 120.4 |
C10—N2—C3 | 106.1 (2) | C14—C13—H13 | 120.4 |
C10—N2—Cd1 | 122.79 (16) | C15—C14—C13 | 120.6 (3) |
C3—N2—Cd1 | 129.23 (15) | C15—C14—H14 | 119.7 |
C4—C3—C8 | 121.3 (2) | C13—C14—H14 | 119.7 |
C4—C3—N2 | 129.8 (2) | C14—C15—C16 | 120.7 (3) |
C8—C3—N2 | 109.0 (2) | C14—C15—H15 | 119.6 |
C5—C4—C3 | 116.7 (3) | C16—C15—H15 | 119.6 |
C5—C4—H4 | 121.7 | C15—C16—C11 | 119.2 (2) |
C3—C4—H4 | 121.7 | C15—C16—N17 | 119.2 (2) |
C4—C5—C6 | 121.3 (3) | C11—C16—N17 | 121.4 (2) |
C4—C5—H5 | 119.3 | C16—N17—Cd1 | 110.21 (15) |
C6—C5—H5 | 119.3 | C16—N17—H17A | 116.2 (19) |
C7—C6—C5 | 122.7 (3) | Cd1—N17—H17A | 93 (2) |
C7—C6—H6 | 118.6 | C16—N17—H17B | 113 (2) |
C5—C6—H6 | 118.6 | Cd1—N17—H17B | 118 (2) |
C6—C7—C8 | 116.1 (3) | H17A—N17—H17B | 105 (3) |
C6—C7—H7 | 122.0 | O20—N18—O21 | 119.1 (3) |
C8—C7—H7 | 122.0 | O20—N18—O19 | 119.7 (2) |
N9—C8—C7 | 132.5 (3) | O21—N18—O19 | 121.1 (2) |
N9—C8—C3 | 105.5 (2) | N18—O19—Cd1 | 117.12 (17) |
C10—N2—C3—C4 | −179.5 (3) | C8—N9—C10—N2 | 0.1 (3) |
Cd1—N2—C3—C4 | −15.2 (4) | C8—N9—C10—C11 | −174.8 (2) |
C10—N2—C3—C8 | 0.4 (3) | N2—C10—C11—C16 | 31.7 (4) |
Cd1—N2—C3—C8 | 164.74 (16) | N9—C10—C11—C16 | −154.1 (2) |
C8—C3—C4—C5 | −0.4 (4) | N2—C10—C11—C12 | −145.3 (2) |
N2—C3—C4—C5 | 179.5 (3) | N9—C10—C11—C12 | 28.9 (4) |
C3—C4—C5—C6 | 0.3 (4) | C16—C11—C12—C13 | −1.0 (4) |
C4—C5—C6—C7 | 0.6 (5) | C10—C11—C12—C13 | 176.1 (3) |
C5—C6—C7—C8 | −1.2 (4) | C11—C12—C13—C14 | 1.3 (5) |
C6—C7—C8—N9 | −178.7 (3) | C12—C13—C14—C15 | −0.2 (5) |
C6—C7—C8—C3 | 1.1 (4) | C13—C14—C15—C16 | −1.0 (5) |
C4—C3—C8—N9 | 179.5 (2) | C14—C15—C16—C11 | 1.3 (4) |
N2—C3—C8—N9 | −0.4 (3) | C14—C15—C16—N17 | −174.2 (3) |
C4—C3—C8—C7 | −0.3 (4) | C12—C11—C16—C15 | −0.2 (3) |
N2—C3—C8—C7 | 179.8 (2) | C10—C11—C16—C15 | −177.2 (2) |
C7—C8—N9—C10 | 180.0 (3) | C12—C11—C16—N17 | 175.1 (2) |
C3—C8—N9—C10 | 0.2 (3) | C10—C11—C16—N17 | −1.9 (3) |
C3—N2—C10—N9 | −0.3 (3) | C15—C16—N17—Cd1 | 120.8 (2) |
Cd1—N2—C10—N9 | −165.88 (16) | C11—C16—N17—Cd1 | −54.5 (3) |
C3—N2—C10—C11 | 174.4 (2) | O20—N18—O19—Cd1 | −172.3 (2) |
Cd1—N2—C10—C11 | 8.8 (3) | O21—N18—O19—Cd1 | 9.7 (3) |
Symmetry code: (i) −x+1, y, −z+3/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N9—H9···O20ii | 0.75 (3) | 2.39 (3) | 3.012 (3) | 140 (3) |
N9—H9···O21ii | 0.75 (3) | 2.51 (3) | 3.238 (3) | 163 (3) |
N17—H17A···O21 | 0.86 (3) | 2.34 (3) | 2.973 (3) | 131 (2) |
N17—H17B···O20iii | 0.79 (3) | 2.24 (3) | 3.024 (3) | 170 (3) |
Symmetry codes: (ii) −x+3/2, y+1/2, −z+3/2; (iii) x, −y+1, z+1/2. |
Funding information
This work was supported by the research fund of Chungnam National University.
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