X-Ray Crystal Structure Analysis of Selected Benzimidazole Derivatives

This chapter describes the X-ray crystal structure analysis of selected benzimidazole derivatives, viz. BIP: 2-(1H-benzimidazol-2-yl)phenol, MBMPBI: 1-(4-methylbenzyl)-2-(4-methylphenyl)-1H-benzimidazole, DPBI: 1,2-diphenyl-1H-benzimidazole, PBIP: 2-(1-phenyl-1H-benzimidazol-2-yl)phenol, FPPBI: 2-(4-fluorophenyl)-1-phenyl-1H-benzimidazole and NPBIBHS: 2-(naphthalen-1-yl)-1-phenyl-1H-benzimidazole benzene hemisolvate. The BIP molecule is planar, and in the crystal, it is arranged in parallel planes, stabilised by π-π interactions and the hydrogen bonds. In MBMPBI, benzimidazole cores of the two independent (A and B) molecules are planar. Two C▬H…N hydrogen bonds link B molecules only, forming centrosymmetric dimers with R22(8) ring motifs. In the DPBI molecule, the benzimidazole core is planar: one hydrogen-bond interaction (C▬H…N) and C▬H…π (three) interaction leading to the three-dimensional arrangement. In the PBIP molecule, the benzimidazole is nearly planar. The hydrogen bonds and a π-π stacking interaction are present in the crystal. In the FPPBI molecule, the benzimidazole unit is almost planar. The C▬H…F hydrogen bonds and weak C▬H…π interactions lead to a three-dimensional architecture in the crystal. In NPBIBHS, the naphthalene fragment lies out of the plane about the benzimidazole core unit. The C▬H…N hydrogen bonds and C▬H…π interactions lead to a three-dimensional architecture in the crystal

N-[4-(2-Morpholino­eth­oxy)phen­yl]acetamide monohydrate

In the title compound, C14H20N2O3·H2O, the geometry about the morpholine N atom implies sp 3 hybridization. In the crystal, symmetry-related mol­ecules are linked by inter­molecular N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds, forming infinite chains along the b axis. The chain structure is further stabilized by intra­molecular C—H⋯O inter­actions

3-Ethyl-4-[3-(1H-imidazol-1-yl)prop­yl]-5-phenyl-4H-1,2,4-triazole dihydrate

In the title compound, C16H19N5·2H2O, the triazole ring makes dihedral angles of 70.61 (6) and 41.89 (8)°, respectively, with the imidazole and benzene rings. The water mol­ecules are involved in inter­molecular O—H⋯N and O—H⋯O hydrogen bonds, which stabilize the crystal packing

4-[2-(4-Meth­oxy­phen­yl)eth­yl]-3-(thio­phen-2-ylmeth­yl)-1H-1,2,4-triazol-5(4H)-one monohydrate

In the title compound, C16H17N3O2S·H2O, the triazole ring makes a dihedral angle of 34.63 (6)° with the benzene ring. The thio­phene ring is disordered over two orientations [occupancy ratio = 0.634 (4):0.366 (4)] which make dihedral angles of 54.61 (16) and 54.57 (31)° with the triazole ring. Inter­molecular N—H⋯O and O—H⋯O hydrogen bonds stabilize the crystal structure

4-[3-(1H-Imidazol-1-yl)prop­yl]-3-methyl-5-(thio­phen-2-ylmeth­yl)-4H-1,2,4-triazole monohydrate

In the title compound, C14H17N5S·H2O, the triazole ring makes dihedral angles of 48.15 (8) and 84.92 (8)° with the imidazole and thio­phenyl rings, respectively. The water mol­ecule is involved in inter­molecular O—H⋯N hydrogen bonding

3-Benzyl-5-methyl-1,2-benzoxazole 2-oxide

In the title compound, C15H13NO2, the isoxazole unit and the attached benzene ring are almost coplanar, making a dihedral angle of 1.42 (8)°. The benzyl ring is inclined to the isoxazole ring by 74.19 (8)° and is in a +sc conformation with respect to the benzisoxazole unit. In the crystal, C—H...O hydrogen bonds link the molecules, forming zigzag chains propagating along the b axis. There are also π–π interactions present involving the isoxazole and benzyl rings [centroid–centroid distance = 3.5209 (10) Å], and C—H...π interactions involving the benzene ring of the benzoisoxazole unit and the methylene bridging group

Crystal structure of 3-({[(thiophen-2-yl)methylidene]hydrazinyl}carbonyl)pyridinium chloride dihydrate

In the title compound, C11H10N3OS+·Cl−·2H2O, the organic cation exhibits a dihedral angle of 21.26 (8)° between the mean planes of the pyridine and thiophene rings, and dihedral angles of 15.11 (9) and 6.49 (9)° between the mean planes of the hydrazide moiety and the pyridine and thiophene rings, respectively. In the crystal, the organic cation, the chloride counter-anion and the two water molecules of crystallization are linked through an intricate hydrogen-bonding network consisting of O—H...O, O—H...N, N—H...Cl, C—H...Cl, C—H...O, N—H...O, O—H...Cl and C—H...S interactions that consolidate a three-dimensional network