STRUCTURE DETERMINATION AND TAUTOMERIC TRANSITION OF 3-AMINO-1{[bis(BENZYLSULFANYL)METHYLIDENE]AMINO}UREA
F. N.-F. How1, N. Jamaluddin1, S. N. Abdul Halim2, V. S. Lee2
1Department of Chemistry, Kulliyyah of Science, International Islamic University Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia
howfiona@gmail.com; howfiona@iium.edu.my
2Department of Chemistry, Universiti Malaya, Kuala Lumpur, Malaysia
Keywords: carbohydrazide, urea derivatives, sulfur based molecule, hydrogen interaction, tautomeric transition
Abstract
The single crystal X-ray analysis of 3-amino-1{[bis(benzylsulfanyl)methylidene]amino}urea shows that the compound crystallizes in the triclinic system with the space group P -1 and Z = 4. The asymmetric unit contains two independent molecules of 3-amino-1{[bis(benzylsulfanyl)methylidene]amino}urea. Both bis(benzylsulfanyl)methylidene groups are in a trans configuration with respect to the C16/O1/N3/N4 and C32/O2/N7/N8 fragments, respectively. The tautomeric transition energies of the three tautomeric forms are calculated at the generalized gradient approximation (GGA) level by the BLYP/DND method to estimate the kinetic and thermodynamic barriers. The keto form has a lower energy than the other two forms. Relatively lower values of kinetic barriers (about 58 kcal/mol for the transition between ( a ) and ( b ) forms) are found.
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