FTIR, FT-Raman and quantum chemical investigations of 4,5-dimethyl-1,3-dioxol-2-one

The FT-IR and FT-Raman spectra of 4,5-dimethyl-1,3-dioxol-2-one have been recorded in the regions 4000–400 and 4000–100 cm−1, respectively. The geometry of compound was optimised with B3LYP method using 6-311++G**, 6-31G** and cc-pVTZ basis sets to characterise all stationary points as minima. The optimised structural parameters of the most stable geometry were used in the vibrational frequency calculations. The force constants obtained from the B3LYP/6-311++G** method have been utilised in the normal coordinate analysis. The temperature dependence of the thermodynamic properties like heat capacity at constant pressure (Cp), entropy (S) and enthalpy change (ΔH0→T) for both the compounds were also determined by B3LYP/6-311++G** method. The total electron density and MESP surfaces of the molecules were constructed by NBO analysis using B3LYP/6-311++G** method to display electrostatic potential (electron + nuclei) distribution, molecular shape, size and dipole moments of the molecule. The electronic properties HOMO and LUMO energies were measured. The influences of methyl groups on the skeletal properties have been investigated.