Crystal Structure of 2-(p-Anilinophenyl)-2-phenylindan-1,3-dione and Its Unexpected Formation

The title compound, 2-(p-anilinophenyl)-2-phenylindan-1,3-dione, was isolated by reacting 2-phenylindan-1,3-dione with N,N-diphenylhydrazine. This compound crystallizes in the monoclinic crystal system in the space group P21/n (#14) with the cell parameters a = 9.837(4)Å, b = 13.221(3)Å, c = 16.325(6)Å, β = 107.914(15)°, Z = 4, and V = 2020.2(12)Å3. The five-membered ring of the indan-1,3-dione core is slightly bent, forming an envelope-like conformation. The crystal structure is stabilized by the N-H…O=C hydrogen bond with a carbonyl oxygen and by the weak C-H…O=C interaction with another carbonyl oxygen.