Synthesis, structural and vibrational properties of 1-(adamantane-1-carbonyl)-3-halophenyl thioureas

1-(Adamantane-1 -carbonyl)-3-(2,4-dichlorophenyl)thiourea (1) and 1-(adamantane-1-carbonyl)-3-(2-bromo-4,6-difluorophenyl)thiourea (2) were synthesized by the reaction of adamantane-l-carbonyl chloride with ammonium thiocyanate to afford the adamantane-1-carbonylisothiocyanate in situ followed by treatment with suitable halogenated anilines. The structures of the products were established by elemental analyses, Fourier transform infrared spectroscopy (FTIR), H-1, C-13 nuclear magnetic resonance (NMR), mass spectroscopy and single crystal X-ray diffraction study. Bond lengths and angles show the usual values. All of three condensed cyclohexane rings of the adamantane residues adopt the usual chair conformation. The molecular conformation of I and 2 is stabilized by an intramolecular (N-H center dot center dot center dot O=C) hydrogen bond which forms a pseudo-six-membered ring. Structural features have been complemented with the joint analysis of the FTIR and Fr-Raman spectra along with quantum chemical calculations at the B3LYP/6-311++G** level. (C) 2012 Elsevier B.V. All rights reserved.