The relationship between redox potentials and torsional angles in 4,4 '-dimethyl N,N '-alkylidene 2,2 '-bipyridinium salts

The redox potentials of 4,4'-dimethyl-N'N'-alkylidene bridged 2,2'-bipyridi nium salts derivatives (DBPAs) can be controlled by changing the N, N'-alky lidene bridge length which changes the conformation of the DBPAs.. In this paper, the torsional angles between the two pyridine rings and the molecula r energy of DBPAs are calculated using a PC based software package (AccuMod el 1.2). The relationship between torsional angle and N, N'-alkylidene brid ge length is discussed. The molecular energy of DBPAs can also be related t o the torsional angles (or N, N'-alkylidene bridge size). Some DBPAs had be en synthesized and their redox potentials measured. The difference in poten tial between ethylene and propylene bridged DBPAs is large enough to make a organic diode through bilayer modified electrode.