THE USE OF THE F-19 NMR-SPECTRA OF FLUOROPYRIDINES AND RELATED-COMPOUNDS TO VERIFY THE STATISTICAL SUBSTITUENT CHEMICAL-SHIFT VALUES OF FLUOROARENES

F-19 NMR data for fluorosubstituted-pyridines, -pyridazines, -pyrimidi nes, -pyrazines and -1,3,5-triazines has been used to verify previousl y published statistical substituent chemical shift (SSCS) values for f luoroarenes. The data also allowed generation of a set of structure fa ctors for aromatic nitrogen heterocycles which allows the signals for these compounds to be predicted from the same set of SSCS values as fl uoroarenes. When these values are used to predict the F-19 NMR signal positions of the nitrogen heterocycles, they give a correlation coeffi cient of predicted versus observed values of 0.987 with a standard dev iation of 4.5 compared with 0.995 and 2.46, respectively, for the fluo roarenes.