Investigation of the effects of solvent, halogen and conformations on vibrational spectrum of some thiophene derivatives

In this study, halogen (F, Cl, and Br) and a solvent (polar and apolar) effect on thiophene-2-carbaldehyde and its halogenated derivatives of molecular conformation and vibrational spectra will be studied experimentally and theoretically. FT-IR and Raman spectra of the molecule and its 9-halogenated derivatives will be recorded experimentally in the study. The optimized geometric parameters, conformational equilibria, normal mode frequencies and corresponding vibrational assignments of molecules will be theoretically examined by means of B3LYP hybrid density functional theory (DFT) method. Furthermore, reliable vibrational assignments have made on the basis of potential energy distribution (PED) will be calculated and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of molecules will have been predicted. Then, polar and apolar solvent effects on the molecules will be studied theoretically and experimentally.