FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

In this study where the FTIR, Raman, (1)H NMR and (13)C NMR spectra of poly(N-vinylimidazole) which can be abbreviated as poly(NVIM) are first reported, a comparison of the experimental and theoretical vibrational spectral data of monomer NVIM and water-soluble poly(NVIM) has been given; such a comparison over the vibrational modes and associated spectral data calculated at B3LYP/6-31+G(d) level of theory for NVIM and its stable dimer forms provided significant contributions for getting a reliable interpretation of the observed vibrational spectra of poly(NVIM). The obtained results revealed that the change from NVIM to poly(NVIM) should be characterized by the disappearance of the CH₂CH bonds of the vinyl group and the appearance of the aliphatic CH and CH₂ bonds. Besides this, the thermal properties of poly(NVIM) were elucidated by thermogravimetric analyses such as TGA, DTA and DSC, while some electronic structure parameters of the most stable dimers of NVIM were investigated through the structure calculations performed by using B3LYP method and 6-31+G(d) basis set within the density functional theory (DFT) methodology.