| A series of monomers with benzene, naphthalene, and anthracene cores disubstituted with heterocycles were studied using cyclic voltammetry, UV/Vis spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. These studies were undertaken to determine how pi-electron delocalization in higher benzenoid aromatics such as naphthalene and anthracene changes as oxidation of the neutral aromatic forms and the concurrent formation of the quinoidal state causes the breaking/formation of localized pi-electron sextets. The information obtained from the monomers provided the necessary foundation for the study of extended pi-conjugated systems such as organic conducting polymers and their use in organic electronics. Therefore, the respective polymers synthesized by electrochemical or chemical means were analyzed using electrochemical methods and high frequency saturation transfer EPR spectroscopy. Our studies of monomeric and polymeric systems with benzene, naphthalene, and anthracene cores showed that the behavior of pi-electrons orthogonal to the conjugation pathway has a significant effect on charge delocalization through the entire system. In addition, clear and observable changes in the electronic structure are seen as these systems are oxidized. To extend these findings, dithienylethene switches with similar architectures were synthesized where the extent of pi-electron delocalization could be modulated by oxidation and the (open/closed) state of the switch. |
