Spectral Characterization and Crystal Structure of 1,2-Bis-(1HH-benzimidazol-2-yl)-ethane Dihydrochloride

e crystal structure of 1,2-bis-(1H-benzimidazol-2-yl)-ethane dihydrochloride (1) was determined by X-ray diffraction at room temperature. e structure of 1 was also characterized by mass, elemental analysis, FT-IR, and NMR spectroscopy techniques. e title compound crystallizes in triclinic system and space group P-1, aa a aaaaaa, bb a babbbbbab, cc a aaaaacabab Å, αα a αaababbbα αα a ababbbbbα γγ a bαaababaab, VV a baαaaabaab Å, ZZ a b. Owing to the anti conformations of –CHb– groups, the entire molecule is relatively �at. H-NMR spectra of 1 show AAXX system characteristics.

In the present study, the structure of 1 (C  H  N  Cl  , Figure 1), a symmetric molecule, is investigated by FT-IR, NMR, mass spectroscopy, and X-ray diffraction.

Experimental
2.1.Materials.All chemicals and solvents were reagent grade and were used as purchased without further puri�cation.
Hand  C-NMR (APT) spectra were run on a Varian Unity Inova 500 NMR spectrometer.e residual DMSOd  signal was also used as an internal reference.FT-IR spectra were recorded in KBr disks on a Mattson 1000 FT-IR spectrometer.e ESI (electron spray ionization) MS analyses were carried out in positive ion modes using a ermo Finnigan LCQ Advantage MAX LC/MS/MS.FT-IR spectra were recorded in KBr disks on a Mattson 1000 FT-IR spectrometer.
2.2.Synthesis of 1. e title compound was synthesized from a 1:2 molar ratio of succinic acid (1.18 g, 10 mmol) and ophenylenediamine (2.16 g, 20 mmol) in 5.5 N HCl (20 mL) according to the literature [28].e crystals suitable for X-ray diffraction were obtained from ethanol : HCl (5%) (90 : 10, v : v) solution at room temperature.e yield of the colourless crystals is 1.91 g yield (73% For the structure solution, 47668 re�ections were collected, 3414 were unique ( int = 0.109); equivalent re�ections were merged.An empirical absorption correction was applied, which resulted in transmission factors ranging from 0.63 to 1.00.e data were corrected for Lorentz and polarization effects.e structure of 1 was solved by SIR92 [29] and re�ned with CRYSTALS [30].e nonhydrogen atoms were re�ned anisotropically.H atoms were treated as riding, with C-H = 0.95(6) Å and  iso (H) = 1.2 eq (C), and were constrained

Results and Discussions
3.1.Spectroscopy. 1 H-NMR and APT spectra of 1 are shown in Figures 2 and 3, respectively.e NMR data of the title compound is very informative for the symmetrical structure.
In the 1 H-NMR spectrum, two double-doublets of AA � XX � system at  H 7.75 (4H) and 7.49 (4H) ppm are distinguished, which are attributed to the benzene protons (Figure 2).In the APT spectra, �ve carbon atom signals are observed as expected.e 152.28 ppm signal belongs to the carbon atom that attached to the two imidazole nitrogen atoms.e 132.23 ppm signal is assigned to the two aromatic quaternary carbon atoms.e hydrogen atoms bonded aromatic carbons appear at the 125.98 and 114.58 ppm values (Figure 3).

Crystal
Description.e details of the X-ray data collection, structure solution, and structure re�nements are given in Table 1.Selected bond distances and angles are listed in Table 2. Selected torsion angles are given in Table 3. Table 4 contains the hydrogen bond geometry parameters.ORTEP-III view of the molecular structure of the title compound is given in Figure 4; crystal packing diagram of 1 is given in Figure 5. e average bond distances and angles for the benzimidazole ring are in agreement with those of the similar  C2-N1-C7-C8 −172(1) T 4: Hydrogen bond lengths (Å) and bond angles ( ∘ ).bis(benzimidazolyl)-substituted compounds [22,23,[32][33][34].

D-H ⋯
Only C8-C9 bond length is different (1.61 Å) from that of the literature (e.g., 1.504 Å) [23].Hydrogen bonding and bond angle values are in agreement with the literature [22,23,35].e crystal structure of 1 is stabilized by intermolecular H⋯Cl⋯H interactions, which lead to the formation of a twodimensional layer (Figure 5).e C-N bond lengths in the imidazole ring are in the range 1.30(1)-1.40(1)Å; these are shorter than the singlebond length of 1.480 Å and longer than the typical C=N distance of 1.280 Å, indicating partial double-bond character.is can be interpreted in terms of conjugation in the heterocycle; the dihedral angles between the six-and �vemembered rings are 1.24 and 6.77 (1) ∘ , showing no exact coplanarity.
As expected, the benzimidazole moieties of the molecule are planar; the displacements of all nine atoms contained in the rings are less than 0.0065(1) Å from the least-squares plane.Planarity of the benzimidazole ring system is usually observed.In the solid state, the conformations of the -CH 2 -groups of 1 are all anti.Owing to the anti conformations, the entire molecule is relatively �at, the largest deviation from planarity being re�ected in the torsion

Conclusion
e crystal structure of 1,2-bis-(1H-benzimidazol-2-yl)ethane dihydrochloride (1) was determined by X-ray diffraction at room temperature.e structure of 1 was also characterized by mass, elemental analysis, FT-IR, and NMR spectroscopy techniques. 1 H-NMR spectra of 1 shows AA � XX � system characteristics.Owing to the anti conformations of -CH 2 -groups, the entire molecule is relatively �at.e crystal structure of 1 is stabilized by intermolecular H⋯Cl⋯H interactions, which lead to the formation of a two dimensional layers.

F 1 :
Chemical diagram of the title compound.

F 2 :
AA � XX � system in the 1 H-NMR spectra of 1.