Common Mass Spectral Fragmentation

Mass Spectrometry The most common mass spectral fragmentation of alkylben-zene derivatives is the cleavage of a benzylic bond to give a resonance-stabilized benzylic cation. For example, in the mass spectrum of -butylbenzene (Figure 16-18),... 

Common Mass Spectral Fragmentation Patterns of Organic Compound Families.8-69... 

COMMON MASS SPECTRAL FRAGMENTATION PATTERNS OF ORGANIC... 

COMMON MASS SPECTRAL FRAGMENTS LOST Thomas J. Bruno and Paris D. N. Svoronos... 

As each functional grotip is discussed in future chapters, mass-spectral fragmentations characteristic of that group will be described. As a preview, though, we Jl point out some distinguishing features of several common functionaj groups. 

The reaction is most commonly associated with the mass spectral fragmentations of carbonyl derivatives. 

The nonclassical thiophenes (6), (12) and (13) show intense molecular ions (over 70%) as well as pronounced doubly charged M2+ ions. Other characteristic fragment ions result from the loss of phenyl or methyl substituents as the case may be. The thiobenzoyl fragment at m/e 121 (10-20%) is another common fragment in these molecules. The mass spectral fragmentation of tetraphenylthieno[3,4-c]thiophene (6) is presented in Scheme 6. 

The mass spectral fragmentation reactions of a number of derivatives used in GC-MS have been reported including a series of esters of the JV-trifluoroacetates [152] and the pertrimethylsilyl derivatives [153-155] and their carbon-13- [156] and deuterium-containing analogues [157]. General reviews of the mass spectra of the common amino acids and their derivatives are also available [151,158]. 

Interpreting Mass Spectra 444 Interpreting Mass-Spectral Fragmentation Patterns Mass-Spectral Behavior of Some Common Functional Groups 449... 

Physical Properties of 1,3,4-Thiadiazoles. Ultraviolet spectra of some 2-benzylideneamino-5-phenyl-1,3,4-thiadiazoles have been reported. The n.m.r. spectral properties and conformational preferences of some open-chain and cyclic aromatic sulphides that contain 1,3,4-thiadiazole units, spectroscopic data of metal (Mn, Fe, Co, Ni, Cu, or Zn) chelates of iV-(5-phenyl-l,3,4-thiadiazol-2-yl)dithiocarbamic acids, conductometric and i.r. and Raman determinations on thirteen complexes of Zn, Cd, or Hg with 2-methyl-5-mercapto-1,3,4-thiadiazole, and thermogravimetry of some noble- and common-metal chelates of 5-amino-l,3,4-thiadiazole-2-thiol were also described, as well as the mass-spectral fragmentation of 2-phenyl-... 

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