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Bulletin of the Chemical Society of Ethiopia

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Spectrophotometric and electrochemical studies of the interaction of cryptand 222 with DDQ and I2 in ethanol solution

Abolfazl Semnani, Hamid Reza Pouretedal

Abstract


Spectrophotometric and electrochemical studies concerning the interaction of cryptand 222 with DDQ and I2 have been performed in ethanol solution. In the case of DDQ, the results are indicative of the formation of C222+ and DDQ- through an equilibrium reaction. The results of I2 indicate the formation of I2-ethanol complex and I3- in the absence of C222. In the presence of C222, the formation of C222I+ and I3- through a non-equilibrium reaction is confirmed. The equilibrium constant of the redox reaction between DDQ and C222 has been calculated from the absorbance mole ratio data, using the nonlinear least square program “KINFIT”. The electrochemical reversibility of I-/I2 couple and irreversibility of DDQ/DDQ- is indicated by amperometry. The behavior of DDQ and I2 has been compared. A comparison with aprotic solvents has also been made.

KEY WORDS: Spectrophotometry, Electrochemistry, Cryptand 222, DDQ, I2


Bull. Chem. Soc. Ethiop. 2006, 20(2), 183-192.




http://dx.doi.org/10.4314/bcse.v20i2.21160
AJOL African Journals Online