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Research Overview
Our research interests are focused on fundamental problems in supramolecular and transition metal catalysis. Based on an interdisciplinary approach combining aspects of organic, organometallic and inorganic chemistry, combinatorial methods are in the center of our studies. We are aiming at solving longstanding catalytic problems such as regioselective C-H bond activation (functionalization) or the design of strain-responsive artificial enzymes.
 
Regioselective Remote C-H Bond Activation.
The development of transition metal catalysts capable of promoting C-H bond activations and functionalizations is highly desirable. As C-H bonds are ubiquitous in organic molecules, the control of regioselectivity poses a great challenge.
Supramolecular Catalysis.
Despite some impressive advances in the field of artificial enzymes, chemists have yet to produce a synthetic equivalent that can rival enzymes in rate acceleration, turnover and specificity. We aim to introduce biochemical models (induced fit and near attack conformations) into the supramolecular world to evaluate these concepts in non-biological systems. By covalently linking guests to receptor units it is envisioned that the alignment and orientation of the guest inside the cavity can be controlled. Distortions in the receptor will affect the stability of intramolecular H-bonds. The resulting strain will be utilized for supramolecular catalysis, e.g. in a Diels-Alder reaction between a furan and a maleimide. A reversible breakup and reformation of imine moieties within the receptor units allows for the generation of a dynamic combinatorial library with diversity in receptor, guest and tether units.
Hydrodehalogenation of Chlorinated Pollutants.
The detoxification of chlorinated organic molecules such as PCBs or dioxin constitutes an unresolved environmental problem. Reductive hydro-dehalogenations were identified as a promising pathway to accomplish that goal. In this project, a 3200 membered library of tetraaza-Ni(I) complexes with tetra- and pentadentate ligands is synthesized via a split and pool method. The structure-activity relationship of the resin-bound catalysts will be assayed in a single container via IR thermography.
Selected Publications
• A reductive recycle strategy for the facile synthesis of molybdenum(VI) alkylidyne catalysts for alkyne metathesis, Zhang, W.; Kraft, S.; Moore, J. S. Chem. Commun., 2003, ASAP.
• Structural Isomers of Aryl-Substituted h3-Propargyl Complexes: h2-1-Metalla (methylene)cyclopropene and h3-Benzyl Complexes. Casey, C. P.; Boller, T. M.; Kraft, S.; Guzei, I. A. J. Am. Chem. Soc. 2002, 124, 13215-13221.
• Formation of Cis-Enediyne Complexes from Rhenium Alkynyl Carbene Complexes. Casey, C. P.; Kraft, S.; Powell, D. R. J. Am. Chem. Soc. 2002, 124, 2584-2594.
• 1,3-Metal Shifts in Rhenium Alkynyl Carbene Complexes. Casey, C. P.; Kraft, S.; Powell, D. R. Organometallics 2001, 20, 2651-2653.
• Intramolecular CH Insertion Reactions of (Pentamethyl-cyclopentadienyl)-Rhenium Alkynyl Carbene Complexes. Casey, C. P.; Kraft, S.; Kavana, M. Organometallics 2001, 20, 3795-3799.
• Dimerization of Rhenium Alkynyl Carbene Complexes by a Process Involving Two 1,1.5 Rhenium Shifts and Coupling of the Remote Alkynyl Carbons. Casey, C. P.; Kraft, S.; Powell, D. R. J. Am. Chem. Soc. 2000, 122, 3771-3772.
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