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A detailed analysis of the complete hydrogen and carbon scrambling and fragmantation reactions of boron‐containing cationic species in the mass spectrometer
Author(s) -
Pasto Daniel J.,
Timony Peter E.
Publication year - 1975
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.1210100308
Subject(s) - fragmentation (computing) , chemistry , cationic polymerization , protonation , mass spectrum , ion , mass spectrometry , boron , fourier transform ion cyclotron resonance , polyatomic ion , ion cyclotron resonance , hydrogen , deuterium , analytical chemistry (journal) , photochemistry , organic chemistry , cyclotron , atomic physics , physics , chromatography , computer science , operating system
A detailed analysis of the mass spectral behavior of trialkylboranes and deuterium and 13 C labeled tri‐ n ‐butylborane, and comparison with the ion cyclotron resonance behavior, have revealed several unique features and herefore unrecognized rearrangement and fragmantation reactions:(1)the occurrence of intial fragmentation of the parent ion with apparently nearly exclusive loss of one complete alkyl radical; (2) the extensive formation of boron‐containing spiecies (>% of the total ion current)in the mass spectrometer relative to the virtual absence (<5%) of such spieces in the ion cyclotron resonance spectrum; (3) the dominant formation of boron‐containing species of the composition [C n H 2n+2 B] + with [C 2 H 6 B]+ generally being the base peak; (4) the formation of appreciable quantities of alkane molecular ions (5 to 10% of the total ion current) up to [R 2 ]+. (from R 3 B); (5) the characterization of a fragmentation reaction involving the loss of CH 2 ; (6) the observation that very extensive hydrogen and carbon scrmbling occurs in the ions formed after the initial fragmentation of the parent ion. A mechanism which satisfactorily accounts for the fragmentation and rearrangement reactions is proposed which involves the reversible formation and rearrangement of protonated boracyclopropanes and cyclopropanes formed by cationic insertions in ß‐CH bonds.