Boron compounds, mass spectra

The dialkyl(alkyl-A/-1H-1,2,4-triazol-3-ylbenzenecarboximidamidato)-boron compounds of type 30 are prepared in analogy to 29 from the corresponding trialkylboranes by reaction with 5-amino-1,2,4-triazole in refluxing xylene and treating the intermediate with a 3- to 5-fold excess of the corresponding aryl nitrile under reflux. The mass spectrum, the NMR spectrum, and IR data are given for the various species. The crystal and molecular structure of 30a has been determined by X-ray diffraction it resembles that of 29f [22]. 

Mass spectral data have frequently been used in the structural determination of boron heterocycles. One paper has been devoted to the mass spectra of some six-membered boron-nitrogen systems. It was concluded that the spectra could be interpreted analogously to their hydrocarbon counterparts. In all cases the molecular peak was the base peak of the spectrum (68T6755). Doubly charged molecular ions, a feature typical of aromatic compounds, are often encountered. It should be noted, however, that some certainly non-aromatic aminoboranes give such doubly charged ions as well. 

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