Intramolecular Charge Transfer in Arylpyrazolines

Arylpyrazoline microparticles dispersed in water are synthesized and their absorption spectra are compared with those in solution. It is found that the absorbance of pyrazoline group in solution of 5-aryl arylpyrazoline is far greater than that in solution of arylpyrazolines with no 5-aryl group. This hyperchromic effect is intensified in 5-aryl arylpyrazoline microparticles. It is indicated that ntramolecular charge transfer exists between pyrazoline group and 5-aryl group and this kind of interaction is increased in their microparticles.