Conclusion
Much closer attention may therefore need to be paid to loss of
organometallic ligands over time in oxidative catalysis and to the
nature of the resulting material. Cp ligand loss is important because
it could pose a problem for interpretation of data in the area, could
complicate determining structureeactivity relationships and
complicate designing catalyst improvements by modifying the ligands. In contrast to the catalyst deactivation that typically accompanies ligand loss in other fields of catalysis, in epoxidation we
seem to generate efficient, even more efficient, catalysts in the form
of molybdates of undefined nature, so we can have catalyst activation. In this case the organometallic ligand is therefore a hindrance, not a help in turnover, but may well help to provide easy
entry into the active species by pumping up the electron density on
the catalyst precursor, making it easy to oxidize in the precatalyst
activation step.