N-Heterocylic Carbenes: Effective tools for Small Molecule Stabilization

Tuesday, September 13, 2016

Dr. Robert Gilliard

Case Western Reserve University

The chemistry of s- and p- block elements has evolved dramatically in recent decades,
catalyzed by the discovery of stable carbenes. One of the most prominent uses of
carbenes is as synthetic tools to aid in the stabilization of highly reactive small molecules.
This presentation will cover the syntheses and molecular structures of N-heterocyclic
carbene-stabilized beryllium species and will culminate with a discussion of our recent
discoveries regarding the synthesis and reactivity of the 2-phosphaethynolate anion,
[OCP] . Sodium phosphaethynolate, Na[OCP], is a remarkably stable species containing
a P≡C triple bond. The [OCP] anion is the phosphorus analogue of the more familiar
isocynate anion [NCO] and is best described as a cross between two resonance
structures, a phosphaethynolate [O−C≡P] (51.7%, NRT) and a phosphaketenide
[O=C=P] (40.2%, NRT). This rapidly evolving synthon has been utilized as a "P" transfer
reagent and as a means to afford highly interesting [4+2] and [2+2] cycloaddition
chemistry. Accordingly, this presentation will highlight the experimental realization of
interesting adducts of P2 and CO.

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