MC 3102

work:+1 212-854-7644

jrn11@columbia.edu

Research Summary

Our research interests cover broad areas of organometallic chemistry and bioinorganic chemistry. The central theme is catalysis. Although we approach problems in a mechanistic way, and use a variety of physical methods, we also synthesize new compounds, ranging from models for metalloenzymes through organometallics to small organic compounds.

Much of our work lies at the interface between inorganic and organic chemistry. We have reported the asymmetric synthesis of -amino acid amides and esters from zirconaaziridines. By using a chiral carbonate we can achieve a dynamic kinetic resolution (or "asymmetric transformation"). The stereochemical outcome depends upon the rate of configuration change of the carbon in the zirconaaziridine ring, so we are studying how this change in stereochemistry occurs. By using related electrophiles (carbodiimides) we can prepare a-amino amidines with control of stereochemistry. We hope that, by using epoxides and/or aziridines as electrophiles, we can devise a general method for preparing and controlling the stereochemistry of 1,3-N,O- and 1,3-N,N-disubstituted carbon chains.

We are also:

1. measuring indirectly the rate at which Fe(II) is taken up by the apoproteins of ribonucleotide reductase and other metalloproteins. While the uptake of Fe(II) causes too little change in the visible spectrum to permit its direct observation, its rate can be deduced from the effect of the apoprotein on the rate of formation of the readily observable complex Fe(II)(ferrozine)₃
2. using metalloradicals such as (C₅Ph₅)Cr(CO)₃)- as catalysts for chain transfer in radical polymerizations. The metalloradical removes Ho from the chain-carrying radical and starts a new chain by transferring it to a monomer.
3. investigating the importance of one-electron reduction in the chemistry of electrophilic boranes such as (C₆F₅)₃B. These boranes are used to activate catalysts for olefin polymerization.
4. trying to improve the enantioselectivity of catalytic hydrogenations that occur by ionic mechanisms. In such reactions H+ and H- are generated from H₂ and transferred separately to the substrate.

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“Zirconium-Catalyzed Carboalumination of α-Olefins and Chain Growth of Aluminum Alkyls: Kinetics and Mechanism”, J. M. Camara, R. A. Petros, J. R. Norton*, J. Am. Chem. Soc., 2011, 133, 5263-5273. 

“Mechanism of Insertion of Alkynes into a ‘Constrained Geometry’ Zirconaaziridine: Dissociation of PMe3 is Faster than from the Corresponding Cp2 Complex” K. E. Kristian, M. Iimura, S. A. Cummings, J. R. Norton*, K. E. Janak, K. Pang, Organometallics 28, 493-498 (2009)

“Synthesis, Electrochemistry, and Reactivity of Half-Sandwich Ruthenium Complexes Bearing Metallocene-Based Bisphosphines” A. P. Shaw, J. R. Norton*, D. Buccella, L. A. Sites, S. S. Kleinbach, D. A. Jarem, K. M. Bocage, C. Nataro*, Organometallics (In Press, 2009)

“Chain-Transfer Catalysis by Vanadium Complexes during Methyl Methacrylate Polymerization” J. W. Choi, J. R. Norton, Inorg. Chim. Acta 130, 4250-4252 (2008) (Special Issue, Robert J. Angelici)

“Direct Measurement of the Rate of Interconversion of Zirconaaziridine Enantiomers”, S. A. Cummings, J. A. Tunge, J. R. Norton, J. Am. Chem. Soc 130, 4669-4679 (2008)

“Initiating Radical Cyclizations By H• Transfer From Transition Metals” J. Hartung, M. E. Pulling, D. M. Smith, D. X. Yang, J. R. Norton*, Tetrahedron 64, 11822-11830 (2008)

“Synthesis and Properties of Carboxy-Substituted Half-Sandwich Ruthenium Complexes with Chelating Bisphosphine Ligands (n⁵-C₅H₄CO₂H)Ru(n²-L)X (X = I, H)” A. P. Shaw, H. Guan, J. R. Norton, J. Organomet. Chem. 693, 1382-1388 (2008)

“Unusually Weak Metal-Hydrogen Bonds in HV(CO)₄(P-P) and Their Effectiveness as H• Donors” J. W. Choi, M. E. Pulling, D. M. Smith, J. R. Norton, J. Am. Chem. Soc. 130, 4250-4252 (2008)

“Using a Two-Step Hydride Transfer to Achieve 1,4 Reduction in the Catalytic Hydrogenation of an Acyl Pyridinium Cation” A. P. Shaw, B. L. Ryland, M. J. Franklin, J. R. Norton*, J. Y.-C. Chen, M. L. Hall, J. Org. Chem. 73, 9668–9674 (2008)

“Electron Exchange Involving a Sufur-Stabilized Ruthenium Radical Cation” A. P. Shaw, B. L. Ryland, J. R. Norton, D. Buccella, A. Muscatelli, Inorg. Chem, 46, 5805-5812 (2007)

“Enantioselective Methylalumination of a-Olefins” R. A. Petros, J. M. Camara, J. R. Norton, J. Organomet. Chem 692, 4768-4773 (2007) (Special Issue, Gerhard Erker)

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