Effects of Substituents on NMR Chemical Shifts and Mass Fragmentation Patterns of 1-Aryl-3-phenylpropanes

The 1H and 13C chemical shifts and the mass spectral fragmentation patterns of 1‐aryl‐3‐phenylpropanes with m‐ or p‐substituents (H, NO2 , Br, Cl, OCH3 , CH3 ) were studied. The electronic effects of the substituents seemed to be transmitted by the through‐space as well as by a through‐bond mechanism, resulting in an inverse correlation in the plot of the chemical shift values of i‐C vs. the Hammett σ values. The mass spectra showed the substituted benzyl fragments as the base peaks when the substituents were electron donating, whereas the benzyl fragment was observed as the base peaks with the electron‐withdrawing substituents.