Study of the DMSO—TCNE Charge-Transfer Complex and Its Kinetics

Abstract

DMSO and TCNE form a strong 1:1 charge‐transfer complex (K_25°C=95.4) with an absorption band located at λ=3720 Å. The high enthalpy of complex formation (−11.3 kcal/mole) leads to an appreciably populated triplet state during complex formation. The EPR signal of the TCNE anion arises, reaches a maximum, and then follows second‐order decay kinetics. The initial intensity of the EPR signal is proportional to the original TCNE concentration in DMSO. A molecular mechanism for the equilibrium reaction between TCNE and DMSO is proposed.