Study on association between o-methoxy-benzylidene-p-aminoaniline with phenols

Abstract EN

The interactions of o-methoxy-benzylidene-p-aminoaniline (MBAA) with phenol, p-methoxyphenol, and p-chlorophenol in n-hexane are studied by using UV spectroscopy.

The study led to the formation of hydrogen bond species of types O – H•••••O and O – H ••••• N between MBAA with phenol and p-methoxyphenol.

The last is appeared from the UV spectra record of MBAA with phenols stated at relative concentrations ratio of phenol / MBAA and p-methoxy phenol / MBAA of values 4 / 1 and 4 / 1 respectively.

Similar result is obtained on using p-chlorophenol at relative concentration ratio of p-chlorophenol / MBAA of a value 4 / 1, with additional appearance of two UV protonated bands at a wavelengths of 463 nm and 474 mm.

These can be of type nitrilium ion N H or oxonium ion O, or both of H them.

The equilibrium constants for hydrogen bond formations of MBAA with phenols stated are included.

The interactions of systems under study are confirmed by thermodynamic method.

These show that ΔH and ΔS have a negative signs, as well as their values which support hydrogen bondings.

Moreover, the processes of non spontaneous hydrogen bonding as observed and evident from the positive values of ΔG are included.

These final abnormal results are unexpected and discussed in details.