The present PhD thesis reports physicochemical studies of several organic compounds. In particular, it was studied the conformational preferences and the intramolecular interactions of dipeptide models, as the Ac-Gly-NHMe and its fluorinated and N-methyl derivatives CF3-C(O)-Gly-NHMe and Ac-Gly-N(Me)2. Furthermore, the present work studies the physicochemistry of intra- and intermoecular long range interactions in several fluorinated organic compounds, as non-usual C-Hp hydrogen bonds with the solvent and CFFC interactions. It was also studied the conformational isomerism of 2-fluoroethanol, 3-fluoropropanol and 4-fluorobutanol and evaluated the importance of CFHO hydrogen bonding formation for its conformational isomerism. Experimental data from 1H and 19F NMR and infrared spectroscopies in several solventes and X-ray diffraction of crystalline structures were used. Some fluorinated compounds are not commercial, which were synthesised and characterised. Moreover, in order to compare and elucidate the experimental results, theoretical chemistry methods were used in several levels, by using DFT functionals with and without dispersion corrections and ab initio methods. In particular, NBO analysis was used to evaluate the contribution of stereoelectronic effects. Long-range interactions were studied by theoretical chemistry topological methods, as the QTAIM, NCI, ELF and DORI. Theoretical calculations of spin-spin coupling constants and frequencies for the isolated structure of these compounds and in solvent, by considering the IEF-PCM implicit solvent model, were also carried out. The results obtained by the experimental and theoretical methods were compared, which provided descriptions of the results that any of them alone could accomplish.
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