Class Summary          11/05/04          Term Paper Guidelines         

 

IMPORTANT DATES            Wed., Dec. 1st              First draught of paper due

                                                Wed., Dec. 8th             Review of other papers due

                                                Tues., Dec. 14th            Final Exam

                                                Fri., Dec. 17th               Final Paper Due

 

11/05   Is the delocalized p-system in benzene a stable electronic structure?

 

            Hiberty, Shaik (1985)

                        Separated p and s contributions in benzene

                        Determined that DEp = -11.4 kcal/mol, therefore p-system would rather be LOCALIZED

                        In other words, it’s not the p-system that makes benzene like it is, it’s the s-system!

 

            REBUTTAL     Bard (1986)

                        Suggested that Hiberty and Shaik’s geometries were not appropriate

 

            NOTE, Hiberty and Shaik immediately responded to the rebuttal in the same issue.

 

 

PAPERS MENTIONED

 

Hiberty, P.C., Shaik, S.S., Lefour, J.M. and Ohanessian, G.  Is the delocalized p system of benzene a stable electronic system?  J. Org. Chem. (1985) 50, 4657-4659.

 

Baird, N.C.  On the driving force for the symmetric structure of benzene and the allyl radical: s or p?  J. Org. Chem. (1986) 51, 3907-3908.

 

Hiberty, P.C., Shaik, S.S., Lefour, J.M. and Ohanessian, G.  The p-distortive propensities in benzene and the allyl radical. A reply to a criticism  J. Org. Chem. (1986) 51, 3908-3909.

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