Conformational stability, r0 structural parameters, barriers to internal rotation and vibrational assignment of cyclobutylamine

Theoretical and experimental vibrational spectroscopic study of 4-(1-Pyrrolidinyl)piperidine

“…The B3LYP density functional model exhibits good performance on electron affinities, excellent performance on bond energies and reasonably good performance on vibrational frequencies and geometries of organic compounds [5][6][7][8][9][10][11][12][13].…”

Vibrational Spectroscopic Investigation and Conformational Analysis of Methacrylamidoantipyrine: A Comparative Density Functional Study

“…Vibrational spectroscopy has been widely used as the standard tool for structural characterization of molecular systems together with DFT calculations [7][8][9][10][11][12][13][14]. DFT is popular as it is a cost-effective procedure for studying the physical properties of molecules.…”

“…Unlike the Hartree Fock theory, DFT recovers electron correlation in the self-consistent KohnSham procedure through the functions of electron density, so it is a cost-effective and reliable method. The DFT/B3LYP model exhibits good performance particularly on vibrational frequencies and geometries of organic compounds [7][8][9][10][11][12][13][14].…”

Conformational stability, r0 structural parameters, and vibrational assignments of mono-substituted cyclobutanes: Fluorocyclobutane

“…However, from a more recent microwave investigation of both the equatorial and axial conformers of chlorocyclobutane [4] it has been possible to obtain the complete structural parameters [5] from the revised rotational constants of the equatorial conformer along with those for axial conformer combined with those predicted from the ab initio MP2(full)/6-311+G(d,p) calculations. By utilizing the ab initio predicted parameters in combination with previously reported microwave rotational constants it has been possible to obtain complete r 0 structural parameters in addition to chlorocyclobutane for cyclobutylamine [6], bromocyclobutane [7], cyanocyclobutane [8], and cyclobutanol [9]. All of these molecules have at least two conformers present at ambient temperature.…”

“…All of these molecules have at least two conformers present at ambient temperature. By variable temperature infrared investigations of rare gas solutions [5][6][7][8][9] the enthalpy differences have been determined after confident vibrational assignments have been made by using ab initio predicted frequencies, infrared band contours and intensities, along with Raman activities and depolarization values. From far infrared and low frequency Raman spectra of the gases it has been possible to obtain the potential function governing the conformational interchange for many of these molecules.…”