Applications of Mass Spectrometry to the Structural Elucidation of Organic Molecules

The mass spectra of complexes derived from reactions of substituted azobenzenes, benzophenoneazines, phenyl hydrazones and benzalanilines with iron carbonyls are discussed and structures proposed. The ability of iron carbonyls to cleave nitrogen-nitrogen bonds and, in some cases, to produce molecular rearrangements within aromatic nitrogen systems is demonstrated. Deuterium labelling at chosen sites within the complexes derived from substituted benzalanilines has elucidated the mechanism of formation and the position from which the hydrogen atom, which is transferred, originates. Discussion is also made on the effect of substitution upon the mass spectral decomposition of these complexes. In other sections the electron impact induced dissociation of cyclopentadienyl mu-mercaptido, mu-alkoxo and mu-dialkyl amido binuclear metal complexes of chromium, iron and nickel are compared according to the effect of the ligand system and the metal atom involved and arguments are proposed which take account of sigma and pi donor and acceptor abilities of the ligands. Deuterium labelling studies are also included to differentiate sites of hydrogen transfer in elimination of cyclopentadiene, benzene and mercaptans from these systems. The formation of the corresponding metellocenes under electron impact is also deliberated upon and effects of the ligand system upon its formation taken into consideration. Finally rearrangement ions occurring in the mass spectra of some polyfunctional cyclopropane systems are compared with known rearrangement processes in related aliphatic compounds and the differences noted are discussed in terms of structure and ion stabilities. In addition rearrangement processes having no precedent in related aliphatic compounds are discussed