Manifestation of intramolecular and intermolecular interactions in infrared absorption spectra of biologically active aminophenols

FTIR methods were used to study intramolecular and intermolecular interactions in solutions and the solid state of the biologically active aminophenols 2-anilino-4,6-di-tert-butylphenol, N-(3,5-di-tert-butyl-2-methoxyphenyl)aniline, and 2,4-di-tert-butyl-10H-1-phenothiazinol. An analysis of the IR spectra has shown that intramolecular interactions between the OH and NH groups occur in solutions of 2-anilino-4,6-di-tertbutylphenol in CCl₄ to form O-H⋯N hydrogen bonds. The NH groups in solutions of N-(3,5-di-tert-butyl-2-methoxyphenyl)aniline in CCl₄ are present in the non-associated state because of the absence of hydroxyl groups in the molecular structure. The OH and NH groups in solutions of 2,4-di-tert-butyl-10H-1-phenothiazinol in CCl₄ do not interact within the molecule due to a decrease in the conformational mobility of the molecular fragments due to the presence of the rigid C_Ar-S-C_Ar molecular bond in this compound. Intermolecular interactions involving the NH groups occur in the solid state of these compounds. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 68–73, January–February, 2008.