Szwarc

Since its inception, the institute, in addition to its regular faculty members, has always had a number of outstanding scientists associated with it as fellows or adjunct facnlty. These include, among others, Ned Arnett, Joe Casanova, Paul Schleyer, Jean Sommer, Gabor Somorjai, Peter Stang, Michael Szwarc (who just recently passed away), Ken Wade, and Bob Williams. They greatly contribnte to onr scientific work by their visits and participation in our symposia and freqnently throngh close research cooperation. Because they are also close friends. 

M. Szwarc and M. Van Beylen, Ionic Polymerisation and Pining Polymers, Chapman and HaU, New York, 1993. 

M. Szwarc, Carbanions, Pining Polymers andPlectron Transfer Processes, Wiley-Interscience, New York, 1968. 

M. Szwarc, Eiving Polymers andMechanisms of Anionic Polymerisation, Spriager-Vedag, Berlin, 1983. 

Stannett and Szwarc have argued that the permeability is a product of a factor F determined by the nature of the polymer, a factor G determined by the nature of gas and an interaction factor H (considered to be of little significance and assumed to be unity). 

M. Szwarc, Ions and Ion Pairs in Organic Reactions, John Wiley Sons, New "Vbrk, 1972. 

Most quantitative studies concern methylation and were carried out by Szwarc and his collaborators. 

The competitive method employed for determining relative rates of substitution in homolytic phenylation cannot be applied for methylation because of the high reactivity of the primary reaction products toward free methyl radicals. Szwarc and his co-workers, however, developed a technique for measuring the relative rates of addition of methyl radicals to aromatic and heteroaromatic systems. - In the decomposition of acetyl peroxide in isooctane the most important reaction is the formation of methane by the abstraction of hydrogen atoms from the solvent by methyl radicals. When an aromatic compound is added to this system it competes with the solvent for methyl radicals, Eqs, (28) and (29). Reaction (28) results in a decrease in the amount... 

Szwarc and his co-workers have measured the methyl affinities (that is, reactivities toward methyl radicals compared with that of benzene) of a number of heterocyclic compounds. These, together with the methyl affinities of some homocyclic compounds, are set out in Table IX. 

It is notable that pyridine is activated relative to benzene and quinoline is activated relative to naphthalene, but that the reactivities of anthracene, acridine, and phenazine decrease in that order. A small activation of pyridine and quinoline is reasonable on the basis of quantum-mechanical predictions of atom localization encrgies, " whereas the unexpected decrease in reactivity from anthracene to phenazine can be best interpreted on the basis of a model for the transition state of methylation suggested by Szwarc and Binks." The coulombic repulsion between the ir-electrons of the aromatic nucleus and the p-electron of the radical should be smaller if the radical approaches the aromatic system along the nodal plane rather than perpendicular to it. This approach to a nitrogen center would be very unfavorable, however, since the lone pair of electrons of the nitrogen lies in the nodal plane and since the methyl radical is... 

M. Szwarc and J. H, Binks, Theoretical Organic Chemistry, p, 262. Butter-worths, London, 1959. 

Affinities toward other alkyl radicals have also been measured by Szwarc and his co-workers using techniques similar to those described above, It is interesting to compare the affinities of naphthalene with those of quinoline toward methyl, ethyl, and n-propyl radicals (Table X). 

On the basis of the reaction of alkyl radicals with a number of polycyclic aromatics, Szwarc and Binks calculated the relative selectivities of several radicals methyl, 1 (by definition) ethyl, 1.0 n-propyl, 1.0 trichloromethyl, 1.8. The relative reactivities of the three alkyl radicals toward aromatics therefore appears to be the same. On the other hand, quinoline (the only heterocyclic compound so far examined in reactions with alkyl radicals other than methyl) shows a steady increase in its reactivity toward methyl, ethyl, and n-propyl radicals. This would suggest that the nucleophilic character of the alkyl radicals increases in the order Me < Et < n-Pr, and that the selectivity of the radical as defined by Szwarc is not necessarily a measure of its polar character. 

M. SZWARC, Department of Chemistry N. Y. State University College of Forestry at Syracuse University... 

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