Ultrasonic and spectral studies on charge transfer complexes of anisole and certain aromatic amines

- Intermolecular H-bonded complexes are identified between anisole and two amines by ultrasonic studies.
- The formation of these complexes is confirmed by UV spectral method.
- Stability constants (K) are determined by ultrasonic and UV-spectral methods.
- The thermodynamic properties are reported for the formation of these complexes.
- The thermodynamic stability of these complexes is confirmed by the sign of ΔG and ΔS values.

Stability constants of two complexes of anisole with aniline and N-methylaniline (NMA) are determined from the measured ultrasonic velocity in n-hexane medium at four different temperatures. Acoustic and excess thermo acoustic parameters [excess ultrasonic velocity (uE), excess molar volume (VE), excess internal pressure (πiE)] are reported for these systems at four different temperatures. The trend in acoustic and excess parameters with concentration in the two systems establishes the formation of hydrogen bonded complexes between anisole and the two amines. Thermodynamic properties are computed for the two complexes from the variation in K with temperature. The formation of these complexes is also established by UV spectral method and their spectral characteristics and stability constants are determined. K values of these complexes obtained by ultrasonic and UV spectroscopic techniques agree well. Aniline forms more stable complex than N-methylaniline with anisole in n-hexane medium.

Two hydrogen bonded complexes of anisole with aniline and N-methylaniline are detected by ultrasonic and UV-spectral methods and their formation constants are determined by the two techniques. The value of K obtained by the two methods are comparable.130