Michael J. S. Dewar


Born September 24th, 1918, in Ahmednagar, India. Emeritus Professor at The University of Florida, USA.

Fellow of the Royal Society (1960); Fellow of the American Academy of Arts and Sciences (1966); Member of the National Academy of Sciences (1983); Honorary Fellow, Balliol College, Oxford (1974); Tilden Medal of the Chemical Society (1954); Harrison Howe Award of the American Chemical Society (1961); Robert Robinson Medal, Chemical Society (1974); G.W. Wheland Medal of the University of Chicago (1976); Evans Award, The Ohio State University (1977); Southwest Regional Award of the American Chemical Society (1978); Davy Medal, Royal Society of London (1982); James Flack Norris Award of the American Chemical Society (1984); William H. Nichols Award of the Americal Chemical Society (1986); Auburn-G. M. Kosolapoff Award of the American Chemical Society (1988); Tetrahedron Prize for Creativity in Organic Chemistry (1989); WATOC Medal (World Association of Theoretical Organic Chemists Meda), (1990).

Author of:

"The Electronic Theory of Organic Chemistry", Clarendon Press, Oxford, 1949. "Hyperconjugation", Ronald Press, New York, 1962. "An Introduction to Modern Chemistry", Athlone Press, London, 1965. "The Molecular Orbital Theory of Organic Chemistry", McGraw-Hill, New York, 1969. "The PMO Theory of Organic Chemistry" (with R.C. Dougherty), Plenum, New York, 1975. "A Semi-empirical Life", American Chemical Society, 1992. 593 papers in chemical journals.

Important Contributions:

  • Tropolone (1945): Formulation of stipitatic acid and colchicine as derivatives of a new aromatic system (tropolone). These were the first cases of compounds containing aromatic rings with other than 5 or 6 atoms.
  • PMO Theory (1952): Development of a qualitative/semiquantitative treatment of organic chemistry (PMO theory) by a rigorous perturbational MO treatment. PMO theory is demonstrably superior to other alternatives and it alone has a rigorous basis in quantum mechanics, a point obscured by misuse of the term to describe a different and unsound PMO-type treatment.
  • π Complexes (1952): Interpretation of certain molecular rearrangements in terms of intermediates (π complexes) containing dative bonds where the donor and/or acceptor orbitals are MOs. Interpretation of metal-olefin complexes as π complexes (often misattributed to Chatt).
  • Borazaro Compounds (1958–70): Discovery of a new class of abnormally stable aromatic organoboron ("borazaro") compounds, derived from normal aromatic compounds by replacing one or more CC pairs by BN. Over 30 systems of this kind have been described.
  • Charge Transfer Interactions (1961): Refutation of Mulliken's charge transfer theory of the bonding in p molecular complexes. (See FMO Theory).
  • Semi-empirical MO Treatments (1965-date): Development of semi-empirical treatments accurate enough and reliable enough to be of practical value in chemistry. Use of these procedures, in conjunction with experiment, has led to major revisions of chemical theory.
  • Pericyclic Reactions (1974-date): "Allowed" pericyclic reactions are rarely synchronous, in violation of the Woodward–Hoffman rules. Ab initio calculations are worthless in this connection unless carried out at a very high level of ab initio theory.
  • Multibond Rule (1984): A reactions in which two or more bonds are formed and broken (multibond reaction) takes place nonsynchronously unless special favor synchronicity.
  • Desolvation Barriers, Enzyme Reactions (1985–89): Before a solvated ion can react with another molecule, one or more molecules of solvent must be removed from it. The activation barriers to reactions of RO- ions with amides in water are of this type and unexpectedly large (>20 kcal/mol). Elimination of such desolvation barriers can account quantitatively for the acceleration of amide hydrolysis by enzymes.
  • FMO Theory (1989): The frontier molecular orbital (FMO) theory has no good basis in quantum mechanics and often leads to predictions that are wholly incorrect.

An obituary can be found at