Inorganic & Organometallic Synthetic Chemistry

We study the chemistry of first-row transition metal compounds

At the University at Buffalo, the Lacy group explores inorganic and organometallic chemistry as a means of building matter with atomic precision. While the construction of everyday objects follows long-understood rules, the assembly of matter at the molecular level—atom by atom—is governed by principles still being uncovered within the chemical sciences. Our group approaches this science using the tools of first-row transition-metal coordination chemistry. By following the logic of synthesis, we identify gaps in chemical knowledge and use experiment to bridge them. Our ongoing story of discovery centers on manganese(III) halide and pseudohalide complexes, a new class of compounds whose capacity for high-potential redox chemistry has deepened our understanding of Mn’s role in life and planetary chemistry.

Why manganese? Our expertise centers on iron, manganese, and titanium—the three most abundant transition metals, and in the case of Fe and Mn, central to life on Earth. Manganese is our current focus because of two questions our discoveries may help answer. One concerns the evolution of photosynthesis: what is the molecular nature of the Mn(II) oxidation that led to the water-oxidizing cluster in photosystem II? The other concerns the degradation of recalcitrant organic matter: what is the molecular basis of this process, and does it have synthetic utility? A single hypothesis underlies both. Mn(III)’s high one-electron reduction potential is the key property—one that has literally shaped the planet’s chemistry. Yet this property has proven very difficult to replicate in synthetic molecular species, and without access to the appropriate forms, generations of chemists have relied on a narrow subset of low-potential manganese compounds.

What we found: This study began with a seed of curiosity: if CrCl₃ and FeCl₃ are stable compounds, where is MnCl₃? Pondering such esoteric questions is what we do, and not without results! By developing stable manganese(III) tri-halide and tri-pseudohalide complexes for the first time, we uncovered a new class of compounds that captures manganese’s extraordinary natural oxidizing power and reactivity never before observed.

A bench-stable Mn(III) trihalide complex.

• Unprecedented access to the chemistry of Mn^IIICl₃ — 10.1021/jacs.2c08509 · 10.1021/jacs.3c03651
• Mn^IIIX₃ compounds are high-potential compounds — 10.1021/jacs.4c03411
• Phosphine-coordinated Mn^IIIX₃ complexes — 10.1021/acs.inorgchem.4c01820
• Ligands tune the reactivity of Mn^IIIX₃ complexes — 10.3390/molecules29194670

Where this goes: Our immediate goal is to define the mechanisms governing Mn(III)-mediated bond formation and oxidation, using the full range of tools in modern physical inorganic chemistry—synthesis, spectroscopy (UV-vis, EPR, XAS), and emerging techniques such as cryo-electron microscopy—to reveal how structure and redox potential govern reactivity.

From there we are pursuing three directions. We are charting the scope of undirected C–H bond functionalization, a long-standing challenge in organic chemistry. We are working to harness transient Mn(IV) intermediates generated through Mn(III) disproportionation, with relevance to catalysis and to the water-oxidizing cluster. And we are applying these insights to other metals—iron, titanium, molybdenum—while tackling the surprisingly difficult problem of synthesizing Mn(I) carbonyl compounds under safe, inexpensive conditions.

Our mission: We train undergraduate and graduate students to think independently, question assumptions, and carry those habits into whatever careers they pursue. By teaching synthesis as both a technical discipline and a way of reasoning, we aim to cultivate scientists who can recognize gaps in understanding and have the creativity and rigor to fill them. If you’ve read this far, it’s worth noting that we also occasionally ponder the meaning of life and the nature of reality—which tends to happen when one spends too much time contemplating the arcane details of transition metal coordination chemistry. So, if these sort of mental exercises get you excited, contact Dr. Lacy to discuss open positions in the group.