THE X-RAY PHOTOELECTRON-SPECTRA OF 1-1 AND 1-2 SALTS FORMED FROM TRIETHYLAMMONIUM AND 7,7,8,8-TETRACYANOQUINODIMETHANE

The X-ray photoelectron spectra of the 1:1 and 1:2 salts formed from the triethylammonium cation (TEAH+) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) have been measured and analyzed in order to investigate the electronic structures and conformations of the salts. The N Is band (398.2 eV) degenerated in the free TCNQ molecule splits into two bands (398.4 eV and 400.3 eV) in the 1:1 salt. This is due to the unequal interactions of the nitrogen atoms of the TCNQ anion radical (TCNQ-) with TEAH+. In the 1:2 salt, the degenerated N Is bands of two free TCNQ molecules split into three bands (398.5, 400.0, and 401.8 eV). This implies that the negative charge is inhomogeneously distributed over two TCNQ molecules, supporting the idea that the electronic structure of the 1:2 salt can be represented approximately as TEAH+-TCNQ--TCNQ0. It is found that, in the 1:2 salt, the neutral TCNQ molecule (TCNQ0) is weakly bound to the TCNQ anion radical (TCNQ-) of the strongly bound 1:1 salt, with their molecular planes parallel. © 1989 The Chemical Society of Japan.