Three novel compounds of 5-trifluoromethoxy-1H-indole-2,3-dione 3-thiosemicarbazone: Synthesis, crystal structures and molecular interactions

• Published in: Journal of molecular structure Vol. 1049; pp. 157 - 164
• Main Authors: Kaynak, Filiz Betül, Özbey, Süheyla, Karalı, Nilgün
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 08-10-2013
• Subjects: 1H-indole-2,3-dione; Crystal structure; Diffraction; Hydrogen bonds; Molecular structure; Phenyls; Pyrroles; Rings (mathematics); Single crystal X-ray diffraction; Thiosemicarbazone; Three dimensional; 1H-indole-2,3-dione; Single crystal X-ray diffraction; Hydrogen bonds; Thiosemicarbazone
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2013.06.039

•5-trifluoromethoxy-1H-indole-2,3-dione 3-thiosemicarbazone derivatives were synthesized.•The structures were determined by analytical, spectral and single XRD methods.•The molecules are linked into three dimensional framework structure by NH⋯N and NH⋯O hydrogen bonds.
5-Trifluoromethoxy-1H-indole-2,3-dione 3-(N-ethyl/benzylthiosemicarbazone) (2a/2b) and 5-trifluoromethoxy-1-morpholinomethyl-1H-indole-2,3-dione 3-(N-ethylthiosemicarbazone) (3a) were synthesized. The structures of the compounds were confirmed by elemental analysis, spectral data and X-ray single crystal diffraction analysis. The morpholin ring which adopts chair conformation and ethylamino group of 3a are disordered over two sets of sites with unequal occupancy. The indole heterocycle is nearly planar and the dihedral angle between the pyrrole and the adjacent phenyl ring is 2.09° (in 2a), 4.61° (in 2b) and 2.16° (in 3a). In all three crystal structures, a strong NH···O hydrogen bond links the flat conjugated HNNCCO fragment into a six-membered ring. The molecules 2a, 2b and 3a have potential groups of proton donors (thiosemicarbazone group) available for hydrogen bonding. The structures 2b and 3a consist of isolated molecules, while that of 2a contains dimers formed by CH⋯O hydrogen bonds. The molecules are linked into three dimensional framework structure by a combination of mainly NH⋯N and NH⋯O hydrogen bonds and weak CF⋯π and π⋯π interactions.