Solid State Investigations of N-Alkyl-Phenazinium TCNQ and TCNQF4 Salts

We report solid state properties of six new N-alkyl-phenazinium TCNQ and TCNQF4 salts. All compounds have very similar magnetic properties. In single crystal ESR studies, thermally activated tripiet spin excitons (TSE) with an unusual motional behaviour are observed. Temperature and orientation dependent spectra are analyzed in respect to fine structures, linewidths, and activation energies. The crystal structures of two closely related compounds, NBP-TCNQ and NBP-TCNQF4, are reported. They reveal a new type of mixed stacking where donors and acceptors form a DD AA sequence. In these two cases, the tripiet ESR spectra are due to π-dimerized (TCNQ-)2 or (TCNQF4-)2 radical anions. The Madelung energies for these ionic lattices are calculated.