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GIAO/DFT studies on 1,2,4‐triazole‐5‐thiones and their propargyl derivatives
Author(s) -
Phalgune Usha D.,
Vanka Kumar,
Rajamohanan P. R.
Publication year - 2013
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4012
Subject(s) - chemistry , tautomer , chemical shift , density functional theory , carbon 13 nmr , computational chemistry , basis set , propargyl , 1,2,4 triazole , structural isomer , ring (chemistry) , molecular geometry , molecule , stereochemistry , organic chemistry , catalysis
Density functional theory (DFT)/Becke–Lee–Yang–Parr (B3LYP) and gauge‐including atomic orbital (GIAO) calculations were performed on a number of 1,2,4‐triazole derivatives, and the optimized structural parameters were employed to ascertain the nature of their predominant tautomers. 13 C and 15 N NMR chemical shifts of 3‐substituted 1,2,4‐triazole‐5‐thiones and their propargylated derivatives were calculated via GIAO/DFT approach at the B3LYP level of theory with geometry optimization using a 6‐311++G** basis set. A good agreement between theoretical and experimental 13 C and 15 N NMR chemical shifts could be found for the systems investigated. The data generated were useful in predicting 15 N chemical shifts of all the nitrogen atoms of the triazole ring, some of which could not be obtained in solution state 15 N HMBC/HSQC NMR measurements. The energy profile computed for the dipropargylated derivatives was found to follow the product distribution profile of regioisomers formed during propargylation of 1,2,4‐triazole thiones. Copyright © 2013 John Wiley & Sons, Ltd.