An experimental and theoretical investigation of free Oxazole in conjunction with the DFT analysis of Oxazole⋯(H₂O)n complexes.

The mid-IR spectrum of Oxazole (Oxa) is recorded. This spectrum is interpreted with the help of B3LYP/6-311++G(d,p) calculations and potential energy distribution (PED) analysis. The experimental spectrum is concordant with the theoretical data.

An FT-IR and DFT study of the free and solvated 4-(imidazol-1-yl)phenol.

In this study, FT-IR spectrum of 4-(imidazol-1-yl)phenol was recorded. Its vibrational frequencies and modes were determined. Vibrational assignments were proposed with the help of B3LYP/6-311++G(d,p) level of calculations.

Experimental and theoretical study on free 5-nitroquinoline, 5-nitroisoquinoline, and their zinc(II) halide complexes.

In this study where the interpretations of the experimental IR and Raman spectra recorded at room temperature for the ligands 5-nitroquinoline (5NQ) and 5-nitroisoquinoline (5NIQ) and also for their Zn(II) halide (halogen: chlorine, bromine, iodine) complexes were first reported, the assignments of the observed fundamental bands were achieved in the light of the vibrational spectral data and total energy distribution (TED) values calculated at B3LYP/6-311++G(d,p) and B3LYP/LANL2DZ levels of theory. The equilibrium geometrical parameters, Natural Bond Orbital (NBO) charges and frontier orbital (HOMO, LUMO) energies of these molecular structures were also calculated at the same level of theory. Comparisons over the corresponding experimental and theoretical data obtained for the title ligands and their complexes revealed that in complex form both ligands bond to Zn(II) ion through their ring nitrogen atoms and NO2 groups at the same time.

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.

A study of the molecular structure and spectroscopic properties of 3-hydroxy-2-quinoxalinecarboxylic acid by experimental methods and quantum chemical calculations.

The mid-IR and Raman spectra of 3-hydroxy-2-quinoxalinecarboxylic acid (3HQC) were recorded. These spectra were interpreted with the help of B3LYP/6-311++G(d,p) calculations and potential energy distribution (PED) analysis. As a result of the calculations, seven tautomers were determined among many stable conformations.

FT-IR and FT-Raman spectroscopic and DFT theoretical studies on 4-azabenzimidazole.

The Becke, three-parameter, Lee-Yang-Parr exchange-correlation functional have been used to study the geometry, relative energy, frequency and intensity of the vibrational bands of the 4-azabenzimidazole (4AB) tautomers and the most stable tautomer's homodimers. FT-IR and Raman spectra of the 4AB have been measured in the regions 4000-100 cm(-1) and 3500-100 cm(-1), respectively for the first time. The stability of 4AB tautomers were reported.