Author : Alhameedi, Khidhir
QUANTUM MECHANICAL INVESTIGATIONS OF STRUCTUREAL AND THERMAL PROPERTIES OF SOME THIADIAZOL DERIVATIVES
journal of kerbala university,
Volume 10, Issue 4, Pages 123-130
This study involved the adoption of the program (Gaussian 03) to use the method of calculating the total (Ab initio of method) according to the Hartree – Fock method (RHF), for the purpose of the expense of dimensional geometry (lengths and bond angles)when the geometry of a balanced, functions thermodynamic, some physical properties, charges for derivatives ring 4-(1,3,4-thiadiazol-2-yl)benzene-1,3-diols.
Have shown calculation results that the compound (R-SiH3) has the highest value of thermodynamic functions (E0,H0,G0,S0,A0) but the compound (R-AlH2) has the highest value of heat capacity (CV,CP ). The results showed that both nitrogen atoms (N9,N8) had the highest negative charge when the compound (R-AlH2) , which makes it a strong legend when Linked to metal and the formation of the complex.
For ( R-AlH2 , R-SiH3 , R-PH2 , R- SH) molecules the calculated some of physical properties ( dipole moment μ in Debye ) , orbital energies (EHOMO , ELUMO in e V ), IP (in e V) , (measurement stability Δ ) , hardness ɳ and Electron Affinity EA ) . Also For these molecules the calculated (ΔHf 0 (in KJ/mole) by using (semi-empirical method AM1 model in MOPAC program). Calculation results have shown that the compound (R-SiH3) the lower value of the heat of formation (the more Stability) as well as has the highest value of ΔE and IP that means it’s the less active between the compounds. This difference in the results come according to the difference of substituted groups.