E. Alexander Hill

E. Alexander Hill

Professor Emeritus

Phone: 414-229-4256
e-mail: alex@uwm.edu

Degree(s):

Ph.D., California Institute of Technology

Research Description

Our research is generally in the field of Physical Organic Chemistry - the investigation of the mechanisms and reactivities of organic compounds. Some specific areas are:

  1. The structures and dynamics of allylic organometallic compounds. For example, we have found that the rate of the reversible magnesium shift of allylmagnesium bromide may be determined from line-broadening in the carbon-13 NMR spectrum:
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  2. Ring-cleavage/cyclization rearrangements of a similar nature occur for organometallic compounds, carbonions, and free radicals. A typical example is the rearrangement of cyclobutylmethyl Grignard reagents:
    eahgr2

    In addition to being a fundamental reaction process in each class of species, the reaction in the cyclization direction is equivalent to the addition step in chain reaction polymerizations.

    We have been interested in determining the detailed mechanisms of these rearrangements, the similarities and differences in the effects of structure on them, and the relationship to polymerization additions. Based on the differences, it is possible to study the behavior of short-lived free radical pairs, and to distinguish between carbanionic and radical reaction intermediates.
  3. Secondary deuterium isotope effects. The replacement of a hydrogen by deuterium can have a subtle effect on equilibrium and rate constants for a reaction, even though the reaction does not involve breaking the bond to the hydrogen in question. Examples that we have studied include:
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    The magnitudes of these isotope effects are determined by the strength and vibrational freedom of the bond to the hydrogen, and can give useful information about the structure and bonding in the transition state. We are particularly interested in the isotope effects upon carbonyl and organometallic reactions.

Selected Publications

"The Nature of the Ring-Opening Process in a Substituted Cyclopropylmethyliron Complex", E.A. Hill and B. Li, Organometallics, 17, 2778 (1998).

"Infrared and Nuclear Magnetic Resonance Spectroscopic Studies of the Structure and Dynamics of Allylic Magnesium Compounds.", E.A. Hill, W.A. Boyd, H. Desai, A. Darki and L. Bivens, J. Organomet. Chem., 514, 1 (1996).

"A Polar Substituent Effect on the Ring-Cleavage Rearrangement of 1-Arylcyclobutylmethyl Grigard Reagents", E.A. Hill and B. Li, J. Orgamomet. Chem. 448, 9 (1993).

"The Effect of Solvent Polarity on the Rate of Rearrangement of 9-(trans2,3 -dimethylcyclopropropylmethyl)-9-borabicyclo{3.3.1]nonane", E.A. Hill and C.A. Foley, J. Orgamomet. Chem. 396 247 (1990).

"Rearrangement and Cleavage of the Grignard Reagent from 5-Chloromethylnorbornene", E.A. Hill, K. Hsieh, K. Condroski, H. Sonnentag, D. Skalitzky, and D. Gagas, J. Org. Chem. 54, 5286 (1989).

"Ring Cleavage Rearrangement of Methyl-Substituted Cyclopropylmethylboranes", E.A. Hill and Y.-W. Park, J. Organmet. Chem. 356, 1 (1988).