Substituenteneinfluss bei der massenspektrometrischen Fragmentierung: Untersuchungen an N‐methyl‐β,β′‐diphenyl‐diäthylaminen. 19. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen

Some different substituted N‐methyl‐β,β′‐diphenyl‐diethylamines (I) were investigated mass spectrometrically. The main fragmentations and their genesis are summarized in Scheme 2. The molecular ion generates the major fragmentions a (m/e 148) and b (m/e (147 + X)); c (m/e 105) is formed from a and d (m/e (104+X)) from b by further decomposition. The logarithms of the ratios of the relative ion intensities a/b, c/a and d/b were correlated according to the Hammett equation with different substituent constants. The following correlation coefficients (at 20ev) were found: r = 0,98 (σ+), r = 0,63 (σ) and r = 0,96 (σ) respectively. On the basis of the above Hammett correlations, the value of this kind of investigation for the elucidation of mass spectral fragmentation mechanisms is discussed.