• NIH Postdoctoral Fellow, California Institute of Technology, CA, 2012-2015
• PhD, University of California-Irvine, CA, 2012
• BS, Colorado State University, CO, 2007

• Organometallic Chemistry
• Bioinorganic Chemistry

We are a group that specializes in small molecule activation. Examples of small molecules are H₂O, O₂, CO₂, CO, and N₂. The fundamental reactions of these small molecules with transition metal ions in enzymes are important in solar energy storage (e.g. photosynthesis) and health (e.g. respiration). Our strategy to gain insight into these reactions is to probe the mechanism with transition metal complexes. To accomplish this task, students who join the Lacy Lab will participate in activities that include the following:

• organic synthesis (ligand & substrate synthesis, organic product analysis)
• inorganic synthesis (transition metal complex synthesis)
• organometallic chemistry (metal carbonyls, metallocenes, photochemistry)
• characterization techniques (electrochemistry, EPR, NMR, FTIR, UV-vis, XRD, MS)
• mechanistic studies (kinetics, substrate monitoring, hypothesis validation)

Organometallic Chemistry – Catalysis

A primary effort in the Lacy research program is the synthesis of new earth-abundant Mn(I) catalysts for green acceptorless chemical transformations. These include (de)hydrogenation reactions and disproportionation of aldehyde substrates. The former reaction class is efficiently catalyzed by metal complexes that carry out “metal-ligand cooperativity” (“MLC”) processes, and only recently have these been discovered possible on Mn(I) ions. The chemistry of these Mn(I)-MLC capable systems have several advantages over typically employed Ru and Fe based catalysts that inspired our efforts herein. The latter set of transformations are typically carried out by aluminum-alkoxide catalysts, but recently we have discovered that phosphine-phenol and phenolate Mn(I) complexes are also competent.

Bioinorganic Chemistry – Designing synthetic oxygenases

Many processes in biology involve the oxidation of organic molecules at iron and manganese enzyme active sites. Such processes often require molecular oxygen (O₂) and serve as inspiration for new methods of using this generously abundant resource to perform synthetic oxidations with earth abundant catalysts. The enzymes that carry out these types of reactions have diverse coordination environments, and therefore understanding the role of primary coordination is challenging. Our approach to obtain understanding into the effects of primary coordination is to systematically alter the coordination environment of synthetic model complexes through ligand design and observe the effect these changes have on spectroscopic properties and reactivities of the biologically relevant metal complexes.

Photochemistry – Molecular approaches to solar fuels

We are also interested in discovering new methods of storing the energy of photons (solar energy) by splitting water into its constituents. Our strategy uses molecular compounds that differ somewhat from the traditional approach. That is, we use single-site organometallic complexes to (1) absorb light, (2) reduce water to H₂, and (3) oxidize water to H₂O₂ or O₂. Most tactics utilize separated three component systems where different compounds (or surfaces) carry out each of the mentioned steps to photochemical water splitting. The advantage of using single-site organometallic compounds to split water is that no sacrificial donor is needed and the molecular nature of the catalyst provides an opportunity to probe the elementary reactions of water oxidation and reduction in ways that are not possible with solid-state catalysts.

• Kadassery, K. J., MacMillan, S. N.; Lacy,* D. C. Bis-phosphine phenol and phenolate Mn(I) complexes: manganese(I) catalyzed Tishchenko reaction. Dalton Trans. 2018, DOI: 10.1039/C8DT02933D
• Surendhran, R.;^‡ D’Arpino, A. A.; ^‡ Bao, Y. S.;^‡ Cannella, A. F.; MacMillan, S. N.; Lacy,* D. C. Deciphering the Mechanism of O₂ Reduction with Electronically Tunable Non-Heme Iron Enzyme Model Complexes Accepted Chem. Sci. 2018, DOI: 10.1039/C8SC01621F
• Cannella, A. F.; Dey, S. K.; MacMillan, S. M.; Lacy,* D. C. Structural Diversity in Pyridine and Polypyridine Adducts of Ring Slipped Manganocene: Correlating Ligand Steric Bulk with a Quantified Non-Ideal Hapticity Parameter. Dalton Trans. 2018, 47, 5171 – 5180. Cover article.
  
• Kadassery, K. J.; Dey, S. K.; Cannella, A. F.; Surendhran,^§ R.; Lacy,* D. C. Photochemical Water-Splitting with Organomanganese Complexes. Inorg. Chem. (2017), 56, 9954–9965. DOI: 10.1021/acs.inorgchem.7b01483
  
• Kadassery, K. J.; Dey, S. K.; Friedman, A. E.; Lacy,* D. C. Exploring the Role of Carbonate in the Formation of an Organomanganese Tetramer. Inorg. Chem. (2017), 56, 8748-8751. DOI: 10.1021/acs.inorgchem.7b01438
  

§ Undergraduate authors; * corresponding authors