Charge Transfer Complexes of Iodine with Aromatic Hydrocarbons

Ultrasonic velocity (U), density (Rho) and viscosity (Eta) were measured in n-hexane solutions containing iodine (acceptor) and benzene, naphthalene, biphenyl or anthracene (donor) at various equimolar concentrations at 303K. The acoustical parameters such as adiabatic compressibility (Kappa), free length (Lf), internal pressure (Pi i) and molecular interaction parameter (Chi) are evaluated. The variation in acoustical parameters with concentration confirms the formation of donor-acceptor complex between iodine and the four arenes. The stability constant (K) and Gibbs free energy of formation (Delta Go) values are reported for the charge transfer (CT) complexes.