Water-splitting and Catalyzed Ester Synthesis with
Organomanganese(I) Carbonyl Complexes
Replacing ruthenium(II) with manganese(I)
Abstract
Metal catalysts are an important component of industrially relevant chemical reactions and aids
in producing massive amounts of chemicals in a short span of time. Unfortunately, a lot of
chemical reactions relevant to society are catalyzed by expensive or toxic metal complexes.
Manganese is a first row transition metal that is earth-abundant and non-toxic. Recently,
manganese compounds have gained a lot of attention in the field of catalysis due to its ability to
catalyze transformations that were previously catalyzed by ruthenium. For this reason, the
research of Karthika Kadassery in the Lacy research group details efforts toward synthesis and
characterization of novel manganese compounds. The findings are that certain manganese
complexes enable the synthesis of ester compounds, which are important molecules in food and
pharmaceutical chemical industry. The manganese compounds also exhibit thermochemical and
photochemical properties that allowed for new strategies of harnessing sunlight into stored
chemical energy. These and other efforts exemplify some of the sustainable science being
conducted in the Lacy research group by Karthika Kadassery.
Coordination chemistry of Mn(I) with tridentate H-POP ligand Coordination chemistry of Mn(I) with bidentate H-PO ligand
Our previous work which led to current study
Acknowledgement
ReferencesCatalysis (Tishchenko reaction)
Karthika J. Kadassery,† Samantha N. MacMillan,§ David C. Lacy*†
† Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260, United States§ Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States
No Catalyst Yield (%)
1 POPMn(CO)3 26
2 {POPMn(CO)3}2 52
3 - 0
4 H-POP 0
5 H-POP + MnBr2 0
6 MnBr(CO)5 0
7 {H-POP}{Mn(CO)4Br}2 0
8 POPMn(CO)3‧HBr 0
1. Kadassery, K. J.; Dey, S. K.; Friedman, A. E.; Lacy, D. C. Inorg. Chem. 2017, 56 (15), 8748.
2. Kadassery, K. J.; Dey, S. K.; Cannella, A. F.; Surendhran, R.; Lacy, D. C. Inorg. Chem. 2017, 56 (16), 9954.
3. Kadassery, K. J.; MacMillan, S. N.; Lacy, D. C. Dalton Trans. 2018, 47 (36), 12652.
4. Kadassery, K. J.; Lacy, D. C. Dalton Trans. 2019, 48, 4467.
5. Kadassery, K. J.; Sethi, K.; Fanara, P. M.; Lacy, D. C. Inorg. Chem 2019, 58 (7), 4679.
6. Kadassery, K. J.; MacMillan, S. N.; Lacy, D. C. Inorg. Chem. 2019, 58 (16), 10527.
7. Kadassery, K. J.; MacMillan, S. N.; Lacy, D. C. Dalton Trans. 2020. Manuscript under review.
3.245 A°
Since the 2016 finding that Mn(I) pincer complexes with bifunctional ligands are active
(de)hydrogenation catalysts, many have been striving to replace expensive Ru-based catalysts
Saudan et. al. Org. ProcessRes. Dev. 2012, 16, 166
Milstein et. al. J. Am. Chem. Soc. 2005, 127, 10840 Beller et. al. Angew. Chem. Int. Ed.. 2016, 55, 15364
Milstein et. al. J. Am. Chem. Soc. 2016, 138, 4298
Photochemical water-splitting
3600 2700 1800 900
0.7
0.8
0.9
1.0
Tra
nsm
itta
nce
Wavenumber (cm-1)
First phenol bound Mn(I) complex
First Mn(I) catalyzed Tishchenko reaction
Coordination induced O–H bond weakening
-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0
-0.02
0.00
0.02
0.04
Cu
rre
nt
(mA
)
Potential (V) vs. Fc/Fc+
200 mV/s
300 mV/s
400 mV/s
500 mV/s
600 mV/s
700 mV/s
• BDFEO–H of H1 ≈ 73 kcal/mol
• BDFEO–H of phenol ≈ 85 kcal/mol
• Coordination induced O-H bond
weakening, ΔBDFE ≈ 10 kcal/mol)
• Soft-homolysis of O-H bond weakened
by coordination has emerging utility in
energy science and chemical synthesis.
Figure. Cyclic voltammogram [1]– in MeCN.
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