Vibrational spectra, tautomerism and thermodynamics of anticarcinogenic drug: 5-Fluorouracil

► The vibrational spectra give important information about the relation between the structure of a biomolecule and the exhibition of its specific properties in real conditions. ► Uracil and its derivatives, constituents of genetic materials play a pivotal role in basic biological processes. ► 5-Fluorouracil (5-FU), a well-known anticancer drug, was first synthesized in 1957 and is being used since then for the treatment of solid tumors.