Electronic Spectral Studies of Some Charge-Transfer Complexes of a Purine Analogue "Of Biological Interest" with Iodine PDF

Keywords

iodine, spectral studies, charge transfer

Abstract

The reaction between 3.7-disubstituted-2.5-diamino-pyrazolo [1,5-a] pyrimidine-6-carbonitriles (OPC) with iodine is studied photometrically in various chlorinated solvents. The results obtained from spectroscopic measurements revealed that in each solvent the (OPC): I, ratio is 1:2 and the charge transfer (CT) iodine complex is assigned the formula (OPC) 1+1,_. Values of the formation constant (k), molar absorptivity (E) and oscillator strength (f) for the I2 (CT) complex were obtained. It was shown that the values of these constants depend entirely on the polarity of the solvent. Where it was indicated that there is a linear correlation between either the oscillator strength or the molar absorptivity and the dielectric constant of the solvent. suggesting a type of interaction between the ionic (CT) complex with the solvent.