Evaluatingproperties of free base, cationic and hydrochloride species of potent psychotropic 4-bromo-2,5-dimethoxyphenethylamine drug

The structural, electronic, topological and vibrational properties of free base, cationic and hydrochloride species of potent psychotropic 4-Bromo-2,5-dimethoxyphenethylamine (2C-B) drug have been evaluated combining the experimental available IR, ATR, Raman, 1H-, 13C-NMR and ultraviolet-visible spectroscopies with DFT calculations by using the hybrid B3LYP/6-31G* method. The properties were predicted in gas phase and in aqueous solutions by using the polarized continuum (PCM) and the universal solvation model. The cationic species of 2C-B shows higher solvation energy, presenting values approximately similar to morphine, scopolamine and heroin alkaloids. NBO calculations suggest that hydrochloride species is most stable in solution while the AIM studies reveal that in the hydrochloride species in gas phase the H-Cl bond shows covalency while in solution is ionic. The gap value for the hydrochloride species in solution is similar to observed for cocaine. The cationic species of 2C-B has a global electrophilicity index higher than some alkaloids. The expected 78, 81 and 84 normal vibration modes for free base, cationic and hydrochloride species of 2C-B were assigned with the corresponding harmonic force fields by using SQMFF methodology. The force constants are reported. The bands observed in the predicted UV-Vis spectra for the free base and hydrochloride species evidence that the cationic species is clearly present in solution, as compared with the experimental ones.