Our group uses molecular inorganic and organometallic chemistry as a tool to address important problems such as sustainable chemical synthesis, environmental remediation, alternative energy storage, and natural product characterization. An overarching theme that connects most (though not all) of our approaches is the cooperation between ≥2 metal sites.
1. Bimetallic Catalysis for C-C and C-X Bond Formation
We develop various types of bimetallic catalytic mechanisms that allow for novel C-C and C-X bond forming methods to emerge, with the goal of discovering new modes of reactivity/selectivity or utilizing earth-abundant catalyst materials in place of precious metal catalysts. Our studies range from synthesis of bimetallic complexes, to characterization and stoichiometric reactivity studies, to catalysis development and mechanistic analysis.
(a) Pye, D. R.; Cheng, L.-J.; Mankad, N. P. Chem. Sci. 2017, 8, 4750.
(b) Karunananda, M. K.; Mankad, N. P. J. Am. Chem. Soc. 2015, 137, 14598.
(c) Mazzacano, T. J.; Mankad, N. P. J. Am. Chem. Soc. 2013, 135, 17258.
2. Models for Multimetallic Catalysis in Biology
Bimetallic and multimetallic cooperation is prevalent in many metalloenzymes that catalyze multielectron redox processes. For example, atmospheric concentrations of the top 2 greenhouse gases, CO2 and N2O, are regulated in part by enzymes with multimetallic catalytic sites. To better understand the properties and mechanisms associated with these biological metal clusters, we synthesize model compounds that mimic their structure and function. We are particularly interested in copper-sulfide clusters relevant to the CuZ site in nitrous oxide reductase and the Mo/Cu site in carbon monoxide dehydrogenase. Our studies range from cluster synthesis and characterization, to spectroscopic/computational analysis of electronic structure, to chemical reactivity studies.
(a) Johnson, B. J.; Antholine, W. E.; Lindeman, S. V.; Graham, M. J.; Mankad, N. P. J. Am. Chem. Soc. 2016, 138, 13107.
(b) Johnson, B. J.; Antholine, W. E.; Lindeman, S. V.; Mankad, N. P. Chem. Commun. 2015, 51, 11860.
3. Other Projects
Preliminary studies are ongoing for a variety of other projects. These include the use of metal-organic frameworks as “crystalline sponges” for the characterization of natural products, and rigorous structure-function studies of candidate molecular electrolytes in next-generation batteries. In addition, we pursue many monometallic catalytic transformations that emerge serendipitously from our bimetallic catalyst development program.
(a) Cheng, L.-J.; Mankad, N. P. J. Am. Chem. Soc. 2017, 139, 10200-10203.
(b) Mazzacano, T. J.; Mankad, N. P. ACS Catal. 2017, 7, 146.
(c) Waldhart, G. W.; Mankad, N. P.; Santarsiero, B. D. Org. Lett. 2016, 18, 6112.