CHAPTER 1 .1 PHOTO0 XXBATION Off PYRID1NIUM BEPAINSS - RBINVB3IIGATI0N OP SHE STRUCTURE OP THE PHOPOO XIPATIOH DIMER OP 3-0XIPO-N-METHYL-5- PHENYL PYRIDINIUM BETAINE 3-0xido-N-substituted pyridinium betaines constitute an a unique class of heterocyclic compounds by virtue of their 1, 3- dipolar character, the parent molecule being 3-hydroxy pyridine. These fall in the class of 6-membered aromatic betaines, a...