Studies in negative ion mass spectrometry. VII—Negative ion mass spectra of copper (II) β‐diketonate complexes

Electron capture processes in a series of copper (II) β‐diketonate complexes of formula Cu[R1COCHCOR2]2 (where R1 is an alkyl, perfluoroalkyl or aryl group and R2 either an alkyl or aryl group) have been examined. Molecular anions, ligand ions and some novel rearrangement ions have been observed with these compounds. Relative intensities of fragment ions were dependent on the substituents R1, R2 as well as the electron energy and compound pressure in the ion source. By operating the mass spectrometer at compound pressures of c. 4×10−6 Torr and higher, reproducible negative ion mass spectra (free from any significant ion‐molecule contributions) have been obtained for all compounds of the series.