Experimental and theoretical structural studies on 4-(2-phenylethyl)-5-(2-furyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione

• Published in: Structural chemistry Vol. 19; no. 3; pp. 391 - 397
• Main Authors: Karayel, Arzu, Özbey, Süheyla
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-06-2008
• Subjects: Chemistry; Chemistry and Materials Science; Computer Applications in Chemistry; Original Research; Physical Chemistry; Theoretical and Computational Chemistry; Ab initio; DFT; 1,2,4-triazole derivatives; Thione-thiol; AM1; X-ray diffraction; Tautomerism; Relative stability
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-008-9293-z

The structural and conformational features of 4-(2-phenylethyl)-5-(2-furyl)-2, 4-dihydro-3H-1,2,4-triazole-3-thione (
1a
), which can be related to the biological activity, have been investigated by X-ray diffraction and molecular modeling techniques. Ab initio method (RHF/6-31G) and density functional theory (B3LYP/6-31G(D)) have been used to calculate structural parameters, conformations, and relative energy of two tautomeric specious (
1a
and
1b
) of the title compound. The geometry and the conformation of the thione form,
1a
, is well reproduced by the DFT (B3LYP/6-31G(D)) method as compared with X-ray structure in which this form is found. The thione form is also predicted to be 14.42 kcal/mol more stable than the thiol form in the gas-phase by the DFT method.