title: Reinvestigation of growth of urea thiosemicarbazone monohydrate crystal.
abstract: The reaction of urea with thiosemicarbazide in 1:1 mole ratio in aqueous solution does not result in the formation of urea thiosemicarbazone monohydrate crystal, as reported by Hanumantharao, Kalainathan and Bhagavannarayana [Spectrochim. Acta A91 (2012) 345-351]. A reinvestigation of the reported reaction reveals that the crystal obtained is the starting material namely thiosemicarbazide, which has been unambiguously confirmed with the aid of infrared and (1)H NMR spectra and single crystal X-ray structure determination. Analysis of (1)H NMR spectrum reveals that thiosemicarbazide exhibits thione-thiol tautomerism in solution. In contrast, thiosemicarbazide exists as the thione tautomer in the solid state.
authors: Department of Chemistry, Goa University, Goa 403 206, India. srini@unigoa.ac.in
authors: Bikshandarkoil R
authors: BR
authors: Srinivasan
authors: Pallepogu
authors: P
authors: Raghavaiah
authors: V S
authors: VS
authors: Nadkarni
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013882:Thiosemicarbazones / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives*
chemical_list: D013882:Thiosemicarbazones; D014508:Urea