Insight into Positional Isomerism of <i>N</i>-(Benzo[<i>d</i>]thiazol-2-yl)-<i>o</i>/<i>m</i>/<i>p</i>-Nitrobenzamide: Crystal Structure, Hirshfeld Surface Analysis and Interaction Energy

• Main Authors: Aqilah Binti Abdul Latiff, Yan Yi Chong, Wun Fui Mark-Lee, Mohammad B. Kassim
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Crystals
• Subjects: nitro; <i>N</i>-(benzo[<i>d</i>]thiazol-2-yl)benzamide; hydrogen bondings; non-covalent interactions; Hirshfeld surface; interaction energies
• Online Access: https://www.mdpi.com/2073-4352/10/5/348

The functionalization of <i>N</i>-(benzo[<i>d</i>]thiazol-2-yl)benzamide with a nitro (NO₂) substituent influences the solid-state arrangement, absorption and fluorescence properties of these compounds. Each of these compounds crystallised in a different crystal system or space group, namely a monoclinic crystal system with <i>P</i>2₁/<i>n</i> and <i>C</i>2/<i>c</i> space groups for <i>o</i>-NO₂ and <i>m</i>-NO₂ derivatives, respectively, and an orthorhombic crystal system (<i>Pbcn</i> space group) for <i>p</i>-NO₂ derivative. The <i>o</i>-NO₂ substituent with intrinsic steric hindrance engendered a distorted geometry. Conversely, the <i>m</i>-NO₂ derivate displayed the most planar geometry among the analogues. The solid-state architectures of these compounds were dominated by the N−H···N and C−H···O intermolecular hydrogen bonds and were further stabilised by other weak interactions. The dimer synthons of the compounds were established via a pair of N−H···N hydrogen bonds. These findings were corroborated by a Hirshfeld surface analysis and two-dimensional (2D) fingerprint plot. The interaction energies within the crystal packing were calculated (CE-B3LYP/6-31G(d,p)) and the energy frameworks were modelled by CrystalExplorer17.5. The highly distorted <i>o</i>-NO₂ congener synthon relied mainly on the dispersion forces, which included π–π interactions compared to the electrostatic attractions found in <i>m</i>-NO₂. Besides, the latter possesses an elevated asphericity character, portraying a marked directionality in the crystal array. The electrostatic and dispersion forces were regarded as the dominant factors in stabilising the crystal packing.