Structural and vibrational study of 2-(2'- furyl)-4,5-1 H-dihydroimidazole

摘要

In this study 2-(2'-furyl)-4,5-1H-dihydroimidazole (1) was prepared and then characterized by infrared, Raman, andmultidimensional nuclear magnetic resonance (NMR) spectroscopies. The crystal and molecular structures of 1 weredetermined by X-ray diffraction methods. The density functional theory (DFT) and second-order Moller-Plesset theory(MP2) with Pople's basis set show that there are two conformers for the title molecule that have been theoreticallydetermined in the gas phase, and that only one of them, conformer I, is present in the solid phase. NMR spectraobserved for 1 were successfully compared with the calculated chemical shifts at the B3LYP/6-311++G** leveltheorized for this conformer. The harmonic vibrational frequencies for the optimized geometry of the latterconformer were calculated at the B3LYP/6-311++G~(**) level in the approximation of the isolated molecule. For acomplete assignment of the IR and Raman spectra in the solid phase of 1, DFT calculations were combined with Pulaysscaled quantum mechanics force field (SQMFF) methodology to fit the theoretical frequency values to the exper-imental ones