ESR and ENDOR Investigations on Various Wurster’s Radical Cations in Solution. Experimental Results, Theoretical Ab Initio, and DFT Calculations

Summary.

ESR and ENDOR spectra are reported of several symmetrical substituted N,N,N′,N′-tetraalkyl-p-phenylenediamine radical cations in solution. Different N,N′-alkyl substituted para-phenylenediamines, like the ethyl, n-propyl, and iso-propyl derivative are compared with the parent N,N,N′,N′-tetramethyl-p-phenylenediamine (Wurster’s Blue Cation). N,N,N′,N′-Tetrabenzyl-p-phenylenediamine, 1,4-dipyrrolidinylbenzene, and N,N′-bis[4-(dimethylamino)phenyl]piperazine are additionally investigated. Experimental and calculated hyperfine coupling constants are compared. Characteristic UV-VIS data and redox potentials in acetonitrile are reported, together with the syntheses of the compounds.