Electronic spectral studies and solvent effects on the reaction of iodine with 1,4,8,11-tetraazacyclotetradecane

Abstract

The reaction between iodine and 1,4,8,11-tetraazacyclotetradecane (TACTD) is studied photometrically in various solvents like CCl4, CHCl3, CH2Cl2 and 1,2-dichloroethane. The results reveal that in each solvent the (TACTD):I2 ratio is 1:2 and the iodine complex is formulated as (TACTD)I+·I3−. The obtained values of the formation constant (K), extinction coefficient (ε) and oscillator strength (ƒ) for the iodine complex are shown to be strongly dependent on the polarity of the solvent. A linear correlation is obtained between either (ƒ) or (ε) and the dielectric constant (D) of the solvent. The important role of the solvent is mainly suggested to be due to the interaction of the ionic iodine complex with the solvent.