A Study of the Donor Properties of the Phenoxachalcogenines.: I. Tetracyanoethylene and Chloranil as Acceptors

Abstract

The phenoxachalcogenines have been studied as donors toward tetracyanoethylene (TCNE) as the acceptor. It was found that the thermodynamic values for the interactions show no significant trends when the chalcogenine atom is varied from Te to Se to S to O. For the four 1:1 complexes studied, the following average values for the thermodynamic properties were obtained at 20 °C (the total range for each quantity is given in parentheses): K = 1.4 (1.0) l mol−1 ΔG = 0.2 (0.4) kcal mol−1, ΔH = −2.0 (0.2) kcal mol−1 ΔS = −7.0 (0.5) cal deg−1 mol−1. The lack of any significant changes in the thermodynamic values is explained on the basis that all of the complexes involve similar interactions, probably of the π–π molecular complex type. The results were essentially the same for the interaction between phenoxatellurine (PTe) and chloranil (TCQ).