High-Resolution electron impact mass spectrometry of five novel organoiron complexes

The high resolution mass spectra of five novel η1‐R substituted Fe(II)(CO)2 η5‐C5H5 complexes are reported. Fragmentation behavior common to all the studied compounds is noted, as well as some ligand‐specific fragmentation. Fragment ions associated with ligand recoordination, ligand substituent transfer and inter‐ligand bond formation are noted. The role of the electron density around the metal center, and in particular the ‘18‐electron’ configuration, on the fragmentation of these compounds is discussed.