Direct Photolysis of Halopyridines in Solutions; Generation of the 2-Pyridyl Cation

抄録

Direct photolyses of 2-halopyridine in various solvents afforded the corresponding ionic products, as well as the radical product pyridine, while 3- and 4-halopyridines produced pyridine exclusively. The formation of the ionic products may occur via the 2-pyridyl cation generated through the initial photo-included homolytic cleavage of the C-X bond followed by electron transfer within the resulting radical pair. The participation of the unshared pair of electrons adjacent to the radical carbon is suggested to be important for releasing the unpaired electron.