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Dr. Donna S. Amenta
Organic Chemistry
Professor of Chemistry and Head
office:  Physics/Chemistry 1186
email: amentads@jmu.edu  
voice:  540-568-6839
fax:  540-568-7938

Research Interests: Over the past several years our attention has centered on the synthesis of crown ether-containing transition metal complexes in which catalytic activity and/or product selectivity is "switched" on or off through binding of simple cations by crown ether units.1,2  One project addresses our hypothesis that the migratory insertion reaction depicted in Scheme 1 for a transition metal carbonyl complex can be accelerated by the addition of added cation when R is a crown ether. There is precedent in the literature to support this hypothesis.   The presence of Lewis acids has been shown to activate the carbon of metal carbonyl complexes toward nucleophilic attack. 3  Included among the reports are increased reactivity induced by cations held in proximity to metal-bonded CO's by crown ether and crown ether-like ligand.4-9  Preliminary studies1,2 performed in our laboratory, suggest that the number of intervening methylene groups between the metal site and the benzo-crown ether are critical in providing the correct  conformation for interaction between a CO and the cation trapped within the crown.  CPKTM molecular models and Sybyl molecular modeling program indicate that a three methylene group spacer provides the flexibility required to place the crown ether in a favorable conformation for complexation with a terminal carbonyl group.  It is therefore proposed that the migratory insertion reaction of a crown ether substituted transition metal carbonyl complexes with a three methylene group space between the metal and the crown ether, Complex 1 (Scheme 1, x = 3) be investigated both in the presence and absence of added cation.  The rates of these reactions will be determined using variable temperature nuclear magnetic resonance spectroscopy (NMR).  Prior to beginning the kinetic studies, complex 1 will be synthesized.  The proposed method for synthesis is a modification of several literature procedures.4  A similar study of a crown ether prototype of complex 1 is well under way.1   Scheme 1

References

  1. K.E. Norton, A.E. Morton, Donna S. Amenta and J.W. Gilje, "Study of Migratory Insertion Reaction of a Molybdenum Complex," presented at the Chemical and Biological Sciences Research Symposium, October 23, 1999, at the University of Maryland, Baltimore, Baltimore, MD.  

  2. Aimee D. Morton, Donna S. Amenta and John W. Gilje, "Crown Ether Functionalized Alkyl Molybdenum Complexes," South East Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November, 1998.  

  3. Richards, T.P., Hamilton, A.D., "p-Acceptor Macrocycles: New Crown Ethers Containing Isocyanide Groups," J. Chem. Soc. Chem. Commun., 1198 (1985).

  4. Collman, J.P., R.G. Fink, J.N. Cawse, J.I. Brauman, "Lewis Acid Catalyzed [Rfe(CO)4]- ALKY Migration Reactions," J. Chem. Soc. Chem., Commun., 100, 4766 (1978).   

  5. Benn, Taarit, Y., J.L. Bilhour, M. LeComte, J.M. Basset, "31P Nuclear Magnetic Resonance and Infrared Spectroscopic Evidence for Co-ordinatively Unsaturated Zerovalent Tungsten by Interaction of W(CO)5L with AlBr3," J. Chem. Soc., Chem. Commun., 38 (1978).  

  6. Nolan, S.P., R.L. de la Vega, C.D. Hoff, "Thermochemical Study of the Lewis Acid Promoted Carbonyl Insertion Reaction," J. Am. Chem. Soc., 108, 7852 (1988), and references therein. 

  7. King, R.B., in Organometallic Synthesis, J.J. Eisch, R.B. King, Eds., "Transition Metal Compounds," Academic Press, New York, 1965.  

  8. Can, M., J. Campo, "Organometallic Chemistry of Systems with Mo_Hg Bonds," J. Chem. Ed.70, 948 (1993). 

  9. Hyde, E.M., B.L. Shaw, I., Shepher, "Comp[lexes of Platinum Metals Crown Ethers Containing Tertiary Phosphino- Substituted Benzo Groups," J. Chem. Soc., Dalton Trans., 1696 (1978).  

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