DFT Study of the 1,3,4-Thiadiazole Ring molecules (Geometry, Thermodynamic functions, IR studies)

Abstract

This study involved the adoption of the program (Gaussian 03) to use the method of calculation the total according to the theory of functions density (DFT) and style (B3LYP) and the use of al-Qaeda (STO-3G) for the purpose of the expense of dimensional geometric (lengths and angles bond) when the geometry of a balanced, charges, functions thermodynamic as well as account and classification of vibrational patterns belonging to the infrared spectrum and the number of (3N-6) for the three molecules derived from the ring (1,3,4-Thiadiazole) (symbolized by the acronym A, B, C). It was found that the compound-C have the highest value Entropy (S⁰) and heat capacity (C_v), as demonstrated by observing the results that most of the atoms belonging to the compound-C be less electron density was largely due to a nitro group substitute effect (-NO₂), which is working to withdrawing the electrons while the compound-B on the contrary.