Three 1‐phenylindolin‐2‐one derivatives displaying different molecular dipole moments and different crystallographic symmetries

Three 1-phenyl­indolin-2-one derivatives, namely 1-phenyl­indolin-2-one, C14H11NO, (I), 5-bromo-1-phenyl­indolin-2-one, C14H10BrNO, (II), and 5-iodo-1-phenyl­indolin-2-one, C14H10INO, (III), have been synthesized and their structures determined. Compounds (I) and (II) crystallized in the centrosymmetric space groups Pbca and P21/c, respectively, while compound (III) crystallized in the polar space group Aea2. Density functional theory (DFT) calculations show that the mol­ecular dipole moment gradually decreases in the order (I) > (II) > (III). The relatively smaller dipole moment of (III) and the larger non-electrostatic inter­molecular inter­actions may be the main reasons for the noncentrosymmetric and polar structure of (III).