F Chemical Shifts of Allenes and Alkynes

4 F Chemical Shifts of Allenes and Alkynes (6 in ppm relative to CFCI3, IJffI in Hz) 

Estimation of Chemicai Shifts of Substituted Pyridines, Pyrimidines, Pyra-zines, and Triazines (8 in ppm) [5] 

To estimate the chemical shifts of substituted 6-ring heteroaromatics, the same increments, Zj, can be used as for substituted fluorobenzenes (see preceding page). However, different base values, Y (as given below), apply depending on the number and position of nitrogens and the position of the fluorine substituent in question  

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