SYNTHESIS, SPECTROSCOPIC, ac CONDUCTIVITY AND THERMAL STUDIES ON Co(III) ACETYLACETONATE-IODINE COMPLEX

A spectrophotometric study of 1:1 donor–acceptor complex, cobalt (III) acetylacetonate (donor) and iodine (σ-acceptor) has been preformed. The equilibrium constants, (K) and the absorpitivity (ε) for the formation of the iodine complex have been calculated. The predicted structure of the solid triiodide charge-transfer complex reported in this study is further supported by thermal, far and mid infrared spectroscopic measurements. Electron transfer from Co (acac = 2, 4-pentanedionate)3 to iodine leads to the formation of an organic semiconductor with the formula of $[{\rm Co}({\rm acac})_3]_2{\rm I}^+.{\rm I}_3^-$. The kinetic parameters (nonisothermal method) for their decomposition have been evaluated by graphical methods using the equations of Freeman–Carroll (FC), Horowitz–Metzger (HM) and Coats–Redfern (CR). The ac conductivity and dielectric properties of $[{\rm Co}({\rm acac})_3]_2{\rm I}^+.{\rm I}_3^-$ have been measured over the frequency 50–106 Hz at temperature 298 K.