Caracterização do haloperidol (C21H23ClFNO2) por espectroscopias Raman e infravermelha, cálculos DFT e propriedades vibracionais a altas pressões

• Ano de defesa: 2019
• Autor(a) principal: Lima, Raphaela de Araújo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Haloperidol; Polimorfismo (Cristalografia); Teoria da densidade funcional; Espectroscopia Raman
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/44752

Haloperidol (HALO), with molecular formula C21H23ClFNO2, is a conventional antipsychotic drug. It is also a widely used tranquilizer for treatments related to psychiatry, obstetrics, and anesthesiology, and its pharmacology has been extensively reported. In this study, the structural stability of HALO crystal was investigated by Raman spectroscopy up to pressures nearly 5,9 GPa. Initially, the X-rays diffraction obtained from the sample confirmed that the material at ambient conditions crystallizes in a monoclinic structure with space group P21/b (C52h). An auxiliary analysis of normal modes of Crystal vibrations was carried out using Density Functional Theory (DFT) calculations with the functional B3LYP and the Gaussian 6-31G+(d) bases as well as an analysis of potential energy distribution ( PED). These results, in accordance with data from the literature and Raman spectroscopy measurements, allowed the identification of most of normal modes of the crystal. The high-pressure effect on the phase stability was studied. In order to subject the material to high-pressures, a pressure cell was used with the mineral oil, nujol, constituting the hydrostatic pressure transmitting medium. The results obtained from the Raman spectrum indicate some changes starting around 2.0 GPa and finishing close to 4.2 GPa, like the disappearance and appearance of some modes, besides discontinuities in the evolution of the frequencies of several vibrational modes. Such changes involved modes located in the region of the external modes while others involved modes of the molecular skeleton and modes participating of hydrogen bonds. At 2.0 GPa we verified a sudden change corresponding to the lattice modes, thus characterizing a structural phase transition. At 4.2 GPa the changes were related to small conformational changes associated with the hydrogen bonds as well as small deformations in the HALO molecules.