Bis(acetyl­acetonato-κ2 O,O′)(2-amino-1-methyl-1H-benzimidazole-κN 3)oxido­vanadium(IV)

Zukhra Ch Kadirova; Dilnoza S Rahmonova; Samat A Talipov; Jamshid M Ashurov; Nusrat A Parpiev

doi:10.1107/S1600536809023113

. 2009 Jun 24;65(Pt 7):m819. doi: 10.1107/S1600536809023113

Bis(acetylacetonato-κ² O,O′)(2-amino-1-methyl-1H-benzimidazole-κN ³)oxidovanadium(IV)

Zukhra Ch Kadirova ^a,^*, Dilnoza S Rahmonova ^a, Samat A Talipov ^b, Jamshid M Ashurov ^b, Nusrat A Parpiev ^a

PMCID: PMC2969291 PMID: 21582741

Abstract

The title mixed-ligand oxidovanadium(IV) compound, [VO(C₅H₇O₂)₂(C₈H₉N₃)], contains a V^IV atom in a distorted octahedral coordination, which is typical for such complexes. The vanadyl group and the N-heterocyclic ligand are cis to each other. The coordination bond is located at the endocyclic N atom of the benzimidazole ligand. Intramolecular hydrogen bonds between the exo-NH₂ group H atoms and acetylacetonate O atoms stabilize the crystal structure.

Related literature

For the activity of vanadium complexes, see: Rehder (1999 ▶). For the crystal structures of acetylacetonate and benzimidazole oxidovanadium(IV) and (V) complexes, see: Maurya (2002 ▶); Caira et al. (1972 ▶); Shao et al. (1984 ▶); Crans et al. (1997 ▶); Maurya et al. (2006 ▶); Akhmed et al. (2004 ▶). For 1-methyl- 2-aminobenzimidazole compounds, see: Borodkina et al. (2003 ▶); Chekhlov (2004 ▶).

Experimental

Crystal data

[V(C₅H₇O₂)₂O(C₈H₉N₃)]
M _r = 412.33
Monoclinic,
a = 8.27120 (10) Å
b = 15.0472 (2) Å
c = 16.1078 (2) Å
β = 104.2646 (14)°
V = 1942.94 (4) Å³
Z = 4
Cu Kα radiation
μ = 4.57 mm⁻¹
T = 293 K
0.25 × 0.12 × 0.08 mm

Data collection

Oxford Diffraction Xcalibur diffractometer
Absorption correction: multi-scan (CrysAlisPro; Oxford Diffraction, 2007 ▶) T _min = 0.544, T _max = 0.694
8892 measured reflections
3720 independent reflections
2983 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.106
S = 1.00
3720 reflections
249 parameters
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: CrysAlisPro (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlisPro; data reduction: CrysAlisPro; 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, 1997 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809023113/su2113sup1.cif

e-65-0m819-sup1.cif^{(23.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809023113/su2113Isup2.hkl

e-65-0m819-Isup2.hkl^{(182.4KB, hkl)}

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
N3A—H3AA⋯O2B	0.86	2.38	2.972 (3)	127
N3A—H3AA⋯O2C	0.86	2.47	3.034 (2)	124

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Acknowledgments

This work was supported by a Grant for Fundamental Research from the Center of Science and Technology, Uzbekistan (No. F 3–142).

supplementary crystallographic information

Comment

Vanadium complexes have attracted interest in recent nears due to their insulin-mimetic action, and to their activity in nitrogen fixation and haloperoxidation (Rehder, 1999). The vanadium atom can have different coordination numbers and forms coordination compounds with a variety of coordination geometries and oxidation states (Maurya, 2002). Limited information is available on the crystal structure of the vanadium complexes of substituted benzimidazoles (Crans et al., 1997; Maurya et al., 2006). Bis(acetylacetonato)oxovanadium, [VO(acac)₂], is a common precursor for the synthesis of the mixed ligand vanadium(IV) and vanadium(V) complexes with the N-containing monodentate ligands (L), [VO(acac)₂L]. Usually these bis-chelated complexes can be cis- or trans- with distorted octahedral configurations (Caira et al., 1972; Shao et al., 1984). In this study, we prepared the mixed-ligand complex of oxovanadium(IV) with bidentate acetylacetonate and the monodentate benzimidazole, 2-amino-1-methylbenzimidazole, and report herein on its crystal structure.

The molecular structure of the title compound is shown in Fig. 1, and geometrical parameters are available from the archived CIF. In this cis-complex, [VO(acac)₂L], the metal center has a slightly distorted octahedral N₁O₅ coordination sphere, assembled by the O—O-donor acetylacetonate, the oxo-group and the pyridine N-atom of the benzimidazole. The angles around the vanadium atom deviate from 90°, being in the range of 80.85 (6) - 99.91 (7) °, and from 180°, being in the range of 164.96 (7) - 179.18 (7)°, due to coordination of the sterically large ligand to the five-coordinate square-pyramidal [VO(acac)₂] complex (Akhmed et al., 2004).

The coordination bond is localized at the endo-cyclic N-atom of the benzimidazole ligand and the bond lengths and angles are similar to those reported for 2-amino-1-methylbenzimidazolium chloride hydrate (Borodkina et al., 2003), and bis(2-amino-1-methylbenzimidazole-N) dichlorocobalt(II) (Chekhlov et al., 2004). The amino-group is coplanar with the methyl-group [torsion angle C8A—N2A—C7A—N3A is 4.3 (4)°] and participates in intramolecular hydrogen bonds with the carbonyl O-atoms (Fig.2 and Table 1).

The V—O bond (V1—O2B) trans to the oxo-group is significally longer (2.1523 (17) Å) than the V—O bonds which are cis to the oxo-group (1.9927 (14) - 2.0139 (14) Å). In contrast the carbonyl bond involving atom O2B (C4B?O2B) is shorter, (1.252 (3) Å), than the other acetylacetonate C?O bonds [1.264 (3) - 1.273 (3) Å]. The V—N bond length, the cis- and trans- V—O bond lengths are comparable to those reported for oxovanadium(IV) species containing acac^- as ligand in a similar orientation (Crans et al., 1997).

Experimental

Equimolar quantities of [VO(acac)₂] (acac = acetnlacetonate) and 2-amine-1-methylbenzimidazole (0.53 g, 1.9 mmol) were refluxed in ethanol for 3 h. The resulting green solution yielded green crystals which were filtered off and washed twice with acetone. Elem. Analysis found: C 52.4, H 6.0, N 10.3, V 12.4%; C₁₈H₂₃N₃O₅V requires: C 52.4, H 5.6, N 10.2,V 12.4%. IR (BRUKER spectrometer, KBr, cm^-1): 3415 s, 3326 s, 1641 s, 1591 s, 1556 s, 1462m, 1373 s, 1273m, 1018m, 1252w, 1198w, 1132w,1052m, 983m, 939m, 787w, 746m, 669w, 590w, 557w, 455w). Crystals of the title compound, suitable X-ray diffraction analysis, were selected directly from the sample as prepared.