Abstract
Charge transfer complex formation between 2-aminopyridine (donor, 2AP) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (acceptor, DDQ) has been studied spectrophotometrically in acetonitrile (CH3CN). The newly formed CF-complex has reddish brown color and is characterized by the appearance of new absorption bands in the 375-650 nm regions where acceptor and donor do not have any absorption. Maximum and constant absorbance of the complex was obtained after 10 min at 20 degrees C with 1 mL 5 x 10(-3) M DDQ in CH3CN. Based on photometric titration method, the stoichiometry of the formed CF-complex was found to be 1:1 [(2AP)(DDQ)]. Minimum-maximum absorbances method has been applied to estimate the formation constant of the complex where it recorded large value confirming its high stability. Molecular orbital calculations utilizing GAMESS computations were carried out in order to record changes in the electronic structure and molecular geometry of the formed CF-complex. In addition, the infrared vibrational frequencies of the complex were computed and compared with experimental results. (C) 2013 Elsevier B.V. All rights reserved.