Background:
- Alfred P. Sloan Research Fellow, 2005-2007
- Camille and Henry Dreyfus Teacher-Scholar Award, 2005
- 2005 IU Outstanding Junior Faculty Award
- IU Summer Faculty Fellowship, 2004
- 2004 Presidential Early Career Award for Scientists and Engineers
- National Science Foundation Faculty Early Career Development (CAREER) Award, 2003
- Camille and Henry Dreyfus New Faculty Award, 2002
- NIH Postdoctoral Fellow, University of Chicago, 2002
- Ford Foundation Postdoctoral Fellow, University of Chicago, 2001-02
Our research program entails synthetic and mechanistic organometallic chemistry, and is focused on the design of novel complexes capable of mediating unusual reactions. The Mindiola group addresses three main topics: Synthesis, reactivity, and mechanistic studies addressing unprecedented transformations. In particular, our group is interested in metallaradicals, especially systems possessing reactive, unsaturated, and electron-rich metal fragments. Students in my group engage in synthetic organometallic chemistry, and develop familiarity with multiple techniques such as multinuclear NMR, EPR, magnetism, X-ray crystallography, IR, Raman, UV-vis, and Cyclic Voltammetry. Most of our work spans the 3d transition metal elements as well as some of the heavy congeners for group 4-6 metals (we also work with Fe, Co, Ni, depleted uranium and the lanthanides). Compounds synthesized and studied during the course of these objectives are intended to challenge current archetypes of structure, bonding, and reaction chemistries. In certain cases, we have explored our systems with the aid of high level DFT methods.
One of our main themes in the group is the assembly of low- coordinate complexes containing metal-ligand multiple bonds. We have discovered that one-electron oxidation processes can readily induce α-hydrogen abstraction concomitant with formation of the metal- ligand multiple bond. As a result, our group has developed synthetic strategies to generate low-coordinate metal complexes containing terminal alkylidene, alkylidyne, and imide functionalities. As expected, these functionalities are highly reactive, and can engage in group transfer, and intermolecular C-H bonds of arenes and alkanes (under mild conditions). In general, early-transition metal alkylidenes are exceedingly nucleophilic, and our group has used this intrinsic property to achieve terminal metal imides, and phosphinidenes from the corresponding alkylidene motif. Our group has also demonstrated that terminal imides and phosphinidenes can be powerful carboamination catalysts as well as group-transfer reagents.
In addition to synthesis and catalysis, our research group is interested in studying low-coordinate transition metal complexes capable of activating and cleaving strong nitrogen-carbon bonds in N- heterocyclic molecules. We are particularly interested in complexes composed of Ti, V, Nb, and Mo. For instance, our group has discovered that unsaturated complexes containing terminal M=CHR and M≡CR linkages can readily ring-open the C-N bond of N- heterocycles such as pyridine and picolenes. These reactions are important to many industrial processes, such as the catalytic activation and removal of nitrogen (as NH3) from coal-based liquids.
Mechanistic details surrounding metal-mediated N-C bond cleavage are important to understanding hydrodenitrogenation (HDN) since the metal's role in promoting this reaction still remains uncertain.
Shown to the left is the molecular structure of the first four- coordinate titanium alkylidene and vanadium alkylidyne species. The sterically demanding β-diketiminate ligand (space filled) provides sufficient protection to allow for a low-coordinate environment. These systems contain the shortest Ti=C (~1.83 Å) and V≡C (~1.67 Å) bonds ever reported and display highly nucleophilic character at carbon.
