Mass spectra of some alkynylmercury compounds

Abstract

The fragmentation, under electron impact, of eleven halogenated, aliphatic, and aromatic alkynylmercury compounds of general structure (XCC)₂Hg has been examined. The dominant fragmentation of organomercury compounds, namely the fission of the carbon–mercury bond, has been observed. The organic fragments formed either by direct fission or by extrusion of mercury fragmented in ways familiar from metal-free systems; losses of C₂H₄, C₂H₂, and H₂ were commonly seen, the proposed fragmentation pathways being supported by the observation of numerous metastable ions. Comparison of the relative metastable ion intensities suggests that the mercury extrusion products from the compounds with X = Et, Pr and Bu^t decompose through the same structures as are formed from the higher alkylbenzenes. Fragmentation of the organic portion competes effectively with mercury–carbon bond cleavage in the mass spectra of the compounds with X = Bu^t and p-MeOC₆H₄. The loss of HgCl₂ from bis-(p-chlorophenylethynyl)mercury is also observed. In the mass spectrum of bis-(p-methoxyphenyl)mercury and bis-(4-phenylbutadiynyl)mercury metastable ion peaks were found corresponding to fragmentations from doubly charged parent ions to doubly charged daughter ions.