PREAMBLEIn common with many Australian organic chemists of my generation, as a graduate student I was trained in the general area of natural products chemistry. In the mid-1960s I continued this work at Cambridge (UK), working with A. R. Todd on aphid pigments. Dudley Williams arrived from Stanford during this period, and my collaboration with him in those early days introduced me to the mysteries and delights of a technique and a topic completely new to me: applied mass spectrometry and the fundamental reactivity of positive ions in the gas phase. Dudley's drive, enthusiasm and scientific curiousity have always been an inspiration to his students and colleagues, and it is therefore of no surprise that after my appointment to Adelaide my students and I continued work in the area of positive-ion mass spectrometry with particular emphasis on rearrangement reactions. Apart from a joint project (with Peter Derrick) on the application of isotope effects on the McLafferty and allied rearrangements,'*' and my recent and arguably belated return to natural product chemistry with our recent structure determination of a variety of amphibian peptides using fast atom bombardment mass spectrometry (FABMS) and other techn i q u e~,~ our work on positive ions terminated in the late 1960s. But this was the catalyst to all of our subsequent work in gas-phase ion chemistry during the next 25 years.
FRAGMENTATION PROCESSES OF MOLECULAR ANIONSTowards the end of the 1960s I decided to commence work on gas-phase negative ions for two major reasons. First, because negative ions are so very important in many condensed-phase reactions of organic and organometallic systems, and I believed that the corresponding gas-phase chemistry would certainly be equally fascinating. The second reason was much more pragmatic: our Hitachi RMU 7D instrument, presumably because of its source design, produced an excellent yield of negative ions following electron impact ionization of many organic substrates. Although the resolution of this instrument left much to be desired, few instruments either then, or indeed subsequently, have bettered its sensitivity for negative-ion formation following electron impact.The prognosis at that time for the useful application of negative ions for analytical purposes in organic chemistry was certainly not promising. Apart from the pioneering work of von Ardenne and colleagues on large organic molecule^,^ early reviews' and an important study by Carl Djerassi and colleagues6 were not particularly favourable in this regard. Major difficulties appeared to be the paucity of formation of molecular anions by the then existing ionization techniques, together with small ion currents then reported to be produced by organic negative ions. Even so, we were not deterred: our long-term aim was to study the chemistry of organic and organometallic negative ions, and any possible analytical application would simply be a bonus.In essence, our initial idea was simple. We wished to study the fragmentations of all 'organic' functional groups ...
