Crystal structures of three 6-aryl-2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazo­les

Three title compounds, namely, 2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]-6-phenyl­imidazo[2,1-b][1,3,4]thia­diazole, C26H19ClN4S, (I), 2-(4-chloro­benz­yl)-6-(4-fluoro­phen­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18ClFN4S, (II), and 6-(4-bromo­phen­yl)-2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18BrClN4S, (III), have been prepared using a reductive condensation of indole with the corresponding 6-aryl-2-(4-chloro­benz­yl)imidazo[2,1-b][1,3,4]thia­diazole-5-carbaldehydes (aryl = phenyl, 4-fluoro­phenyl or 4-bromo­phen­yl), and their crystal structures have been determined. The asymmetric unit of compound (I) consists of two independent mol­ecules and one of the mol­ecules exhibits disorder of the 4-chloro­benzyl substituent with occupancies 0.6289 (17) and 0.3711 (17). Each type of mol­ecule forms a C(8) chain motif built from N—H⋯N hydrogen bonds, which for the fully ordered mol­ecule is reinforced by C—H⋯π inter­actions. In compound (II), the chloro­benzyl unit is again disordered, with occupancies 0.822 (6) and 0.178 (6), and the mol­ecules form C(8) chains similar to those in (I), reinforced by C—H⋯π inter­actions involving only the major disorder component. The chloro­benzyl unit in compound (III) is also disordered with occupancies of 0.839 (5) and 0.161 (5). The mol­ecules are linked by a combination of one N—H⋯N hydrogen bond and four C—H⋯π inter­actions, forming a three-dimensional framework.