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4
| CONCLUSIONS
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A series of monometallic and heterobimetallic complexes
based on N,O‐chelating ligands were synthesised and isolated
in good yields. These complexes were characterised using
various analytical and spectroscopic techniques, and they
are stable at room temperature. The catalytic potential of
the complexes was evaluated in the monophasic
hydroformylation of 1‐octene at 95°C and 40 bar. The
ferrocenylimine mononuclear catalyst precursors (4a and
4b) were inactive in the hydroformylation experiments. The
Rh(I) mononuclear (2a and 2b) and the ferrocenylimine–Rh
(I) heterobimetallic (5a and 5b) complexes showed excellent
and comparable catalytic activity in the hydroformylation of
1‐octene. These active catalyst precursors also registered
remarkable chemoselectivity towards aldehydes, with no side
products (isomers) observed. Overall, the presence of the
ferrocenyl framework linked to Rh(I) via a bis‐imine spacer
for monophasic hydroformylation of 1‐octene is comparable
(activity and regioselectivity) to the data reported for similar
compounds in a biphasic medium.[60] A rigid aryl spacer
between the ferrocene and the rhodium metal centre may
allow ferrocene to influence the electronic properties of the
catalytic active species and improve on the efficiency of the
heterobimetallic complexes.
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ACKNOWLEDGMENTS
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We thank the University of Cape Town (UCT), the
Department of Science and Technology of South Africa and
NRF‐DST Centre of Excellence in Catalysis – c*change for
financial support.
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