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Solvation enthalpy and the thermodynamics of hydration of trans-cyclohexyl-1,4-...
Tomé, Luciana I. N.; Jesus, A. J. Lopes; Castro, R. A. Esteves de; Teixeira, M. Helena S. F.; Canotilho, João; Eusébio, M. Ermelinda S.The enthalpy of solution of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine in water was determined by calorimetry. The enthalpy of hydration was determined from this quantity and from the enthalpy of sublimation/vaporization presented in another paper by the authors. Considering the solvation process resulting from cavity creation in the solvent and variation of solute conformation transfer steps, ...
Infrared spectroscopy of racemic and enantiomeric forms of atenolol
Castro, R. A. Esteves de; Canotilho, João; Barbosa, Rui M.; Redinha, J. SimõesThe molecular structure of conformational isomorphs given by X-ray diffraction for racemic and enantiomeric atenolol were optimized at the HF/6-31G* level of theory and the infrared spectra of the structure were calculated. These spectra are used to characterize the differences between the various atenolol conformers. ; http://www.sciencedirect.com/science/article/B6VNG-4M3R2CM-5/1/b10f1bad0cbecc44994eccae4c...
Conformational Isomorphism of Organic Crystals: Racemic and Homochiral Atenolol
Castro, R. A. Esteves de; Canotilho, João; Barbosa, Rui M.; Silva, M. Ramos; Beja, A. Matos; Paixão, J. A.; Redinha, J. SimõesX-ray diffraction analysis of (R,S)- and S-atenolol crystalline forms was performed. The crystals studied were grown from evaporation of an ethanol/water solution. (R,S)-Atenolol crystallizes in the centrosymmetric space group C2/c, and S-atenolol crystallizes in a noncentrosymmetric space group C2. There is one symmetry independent molecule in (R,S)-atenolol crystals and two symmetry independent molecules in S...
Infrared study of the acidic and basic forms of betaxolol
Canotilho, João; Castro, R. A. Esteves de; Helena, M.; Teixeira, S. F.; Leitão, M. Luísa P.; Redinha, J. SimõesBetaxolol and its respective hydrochloride salt were studied in solution by computational calculations and infrared spectroscopy. The solution molecular conformations were taken to be the same as those exhibited by the compounds in the solid state given by X-ray diffraction and calculated after full geometry optimization by ab initio Hartree-Fock methods using the 6-31G(d) basis set. Infrared spectra of carbon ...
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