Infrared Spectroelectrochemical Investigation of the Ion Pairing Reactions of the Anions and Dianions of TCNE (Tetracyanoethylene) and TCNQ (Tetracyanoquinodimethane)

摘要

The infrared spectra of the dianions of tetracyanoethylene (TCNE) and tetracyanoquinodimethane (TCNQ), generated electrochemically in acetonitrile, are dependent upon the supporting electrolyte. In particular, the C-N triple bond stretching wavenumbers are higher in the presence of alkali metal salts than in the presence of tetraalkylammonium salts, and the magnitude of the shift is correlated with a positive shift in the half-wave potential of the second reduction wave. The shifts in wavenumber and half-wave potential are attributed to contact ion pairing between the dianion and the alkali metal cation. No such shifts are observed for the anion radicals of TCNE and TCNQ in acetonitrile, nor for the dianion of TCNE in dimethylsulfoxide. (AW)