Vortrag - Prof. Ofial

Im Rahmen der gemeinsamen Kolloquien der Fakultät für Chemie und chemische Biologie der Technischen Universität Dortmund hält

PD Dr. Armin R. Ofial

Ludwig Maximilian University of Munich

einen Vortrag mit dem Thema:

"Construction of Philicity Scales for Polar Organic Reactions"

Abstract:

The kinetics of the reactions of a set of reference electrophiles with a wide range of structurally diverse nucleophiles can be expressed by equation (1), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by two solvent‐dependent parameters, the nucleophilicity N and the susceptibility sN (typically 0.6 < sN < 1.1).

lg k20°C = sN (E + N)   (1)

By using para‐ and meta‐substituted benzhydrylium ions (Ar2CH+) and structurally related quinone methides as reference electrophiles the most comprehensive nucleophilicity scale presently available was developed. In this way a direct comparison of the nucleophilicities of alkenes, allylsilanes, enol ethers and enamines, carbo‐ and heterocyclic arenes, carbanions, ylids, diazoalkanes, O‐, N‐, and P‐centered nucleophiles, as well as hydride donors became available. In combination with analogously derived electrophilicity scales absolute rate constants (k20°C) of numerous polar reactions can be predicted with an accuracy of factor 10‐100. Scope and limitations of the predictive power of equation (1) will be discussed.

Betreuer: Prof. Steffen