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)-4H-imidazo[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 14;(1) 14;Å and makes a dihedral angle of 21.9 14;(8)° with the mean plane of the imidazolopyridine moiety, giving the molecule a V-shape. In the crystal, the imidazolopyridine units are associated through slipped p-p stacking interactions together with weak C-HPyr..ONtr and C-HBrmdcyl..ONtr (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 14;(3):0.098 14;(3) ratio. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H..H (48.1%), H..Br/Br..H (15.0%) and H..O/O..H (12.8%) interactions. The optimized molecular structure, using density functional theory at the B3LYP/6-311 14;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.