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Jack Norton

MC 3102

work:+1 212-854-7644

jrn11@columbia.edu

Norton Research Group
Selected Publications

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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Publications
“Effectiveness in Catalyzing Carboalumination Can Be Inferred from the Rate of Dissociation of M/Al Dimers." R.A. Petros and J.R. Norton*, Organometallics, in press.

“Synthesis and Reactivity of Zirconaaziridines." Cummings, S.A.; Tunge, J.A.; Norton, J.R. In New Aspects of Zirconium-Containing Organic Compounds; Marek, I., Ed.; Springer-Verlag, in press.

“The Effect of Steric Congestion on the Activity of Chromium and Molybdenum Metalloradicals as Chain Transfer Catalysts during MMA Polymerization.” L. -H. Tang and J.R. Norton*, Macromolecules, 2004, 37, 241-243.

“A Vibrational Study of the Diosmacyclobutene Complex Os2(CO)8(µ2-η1, η1-C2H2): The Use of Organometallic Complexes as Vibrational Models for Chemisorbed Ethyne.” C. E. Anson, N. Sheppard, R. Pearman, J. Moss, P. Stößel, S. Koch, and J.R. Norton*, Physical Chemistry Chemical Physics 2004, 6, 1070-1076.
http://www.rsc.org/CFmuscat/intermediate_abstract.cfm?FURL=/ej/CP/2004/b309979b.PDF

“Inverse Temperature Dependence of Chain Transfer Rate Constant for a Chromium Metalloradical in Ploymerization of MMA.” L. -H. Tang, J. R. Norton*, and J. C. Edwards, Macromolecules, 2003, 36, 9716-9720.

"Effect of Chelate Ring Size on the rate of Hydride transfer from CpRu(P-P)H (P-P = Chelating Diphosphine) to an Iminium Cation." H. -R. Guan, M. Iimura, M. P. Magee, J. R. Norton*, and K. E. Janak, Organometallics 2003, 22, 4084-4089.

"Kinetics and Thermodynamics of H• Transfer From (η5-C5R5)Cr(CO)3H (R = Ph, Me, H) to Methyl Methacrylate and Styrene." L. -H. Tang, E. T. Papish, G. P. Abramo, J. R. Norton,* M. -H. Baik, R. A. Friesner, and A. Rappé, J. Am. Chem. Soc. 2003, 125, 10093-10102.

“Asymmetric Synthesis of Silylated α-Amino Acid Esters through Dynamic Kinetic Resolution. ” J.-X. Chen, J. A. Tunge, and J. R. Norton*, J. Org. Chem. 2002, 67, 4366-4369.

“Indirect Determination of the Rate of Iron Uptake into the Apoprotein of the Ribonucleotide Reductase of E. coli..” N. J. Umback and J. R. Norton*, Biochemistry 2002, 41, 3984-3990.

“Protonation of Transition Metal Hydrides to Give Dihydrogen Complexes: Mechanistic Implications and Catalytic Applications”. Papish, E. T.; Magee, M. P.; Norton, J. R. In Recent Advances in Hydride Chemistry; Poli, R., Ed.; Elsevier: New York, 2001; Chapter 2, pp 39–74.


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