Crystal structure, Hirshfeld surface analysis and DFT studies of 6-bromo-3-(12-bromododecyl)-2-(4-nitrophenyl)-4H-imidazo[4,5-b]pyridine

The title compound, C24H30Br2N4O2, consists of a 2-(4-nitrophenyl)-4Himidazo[4,5-b]pyridine entity with a 12-bromododecyl substituent attached to the pyridine N atom. The middle eight-carbon portion of the side chain is planar to within 0.09 (1) degrees and makes a dihedral angle of 21.9 (8)degrees with the mean plane of the imidazolopyridine moiety, giving the molecule a V-shape. In the crystal, the imidazolopyridine units are associated through slipped pi-pi stacking interactions together with weak C-H-Pyr center dot center dot center dot O-Ntr and C-H-Brmdcyl center dot center dot center dot O-Ntr (Pyr = pyridine, Ntr = nitro and Brmdcyl = bromododecyl) hydrogen bonds. The 12-bromododecyl chains overlap with each other between the stacks. The terminal -CH2Br group of the side chain shows disorder over two resolved sites in a 0.902 (3):0.098 (3) ratio. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H center dot center dot center dot H (48.1%), H center dot center dot center dot Br/Br center dot center dot center dot H (15.0%) and H center dot center dot center dot O/O center dot center dot center dot H (12.8%) interactions. The optimized molecular structure, using density functional theory at the B3LYP/6-311 G(d,p) level, is compared with the experimentally determined structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.