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Amidine mass spectral fragmentation patterns
Author(s) -
Barker James,
Jones Michael,
Kilner Melvyn
Publication year - 1985
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210201006
Subject(s) - fragmentation (computing) , amidine , chemistry , substituent , cleavage (geology) , electron ionization , mass spectrum , ion , nitrogen , stereochemistry , polyatomic ion , bond cleavage , mass spectrometry , medicinal chemistry , crystallography , catalysis , organic chemistry , materials science , chromatography , fracture (geology) , computer science , composite material , ionization , operating system
Electron impact mass spectrometry of a range of amidines (R′NC(R)NHR′) including formamidines, acetamidines, benzamidines and tert ‐butylamidine, has been undertaken, and comparisons made of the fragmentation pathways followed by the different families of compounds. Fragmentation of all the molecular ions is characterized by skeletal carbon‐nitrogen bond cleavage to form [R′NCR] + and [R′NH] + fragments, both of which are observed. For formamidines (RH), the positive charge remains with the [R′NH] + fragment which leads to the base peak at m / z 93 corresponding to [R′NH 2 ] + ˙. In contrast, for acetamidines and benzamidines the charge prefers to remain with the [R′NCR] + fragment which gives the base peak for these compounds. The spectra of unsubstituted amidines (HNC(R)NH 2 ) are characterized by cleavage of the carbon substituent from the NCN skeleton, [CN 2 H 3 ] + ( m / z 43) being produced in all cases.