Presentation Title

Post-Transition State Bifurcations in Borole-Alkyne Cycloadditions

Faculty Mentor

Kendall N. Houk

Start Date

23-11-2019 10:45 AM

End Date

23-11-2019 11:30 AM

Location

216

Session

poster 4

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Unsaturated boron heterocycles have emerged as promising building blocks for functional materials in chemical sensing and organic electronics due to their interesting electronic structures. The five-membered borole ring is a four-electron antiaromatic system, isoelectric to the C5H5+ cyclopentadienyl cation. Antiaromatic destabilization renders boroles highly reactive toward cycloadditions and nucleophilic attacks at the tricoordinate boron atom. Experimental reactions of boroles and alkynes are often observed to yield different products (or mixtures thereof) depending on the nature of the substituents. In addition, many of the product structures are valence tautomers, and can interconvert via a web of thermally allowed pericyclic processes. Density functional theory (DFT) computations were performed in Gaussian 09 to study cycloadditions of both unsubstituted and substituted boroles and alkynes. Molecular geometries were optimized using the ωB97XD functional and the 6-31G(d) basis set. Quasi-classical molecular dynamics simulations were performed at the same level of theory. We report the first molecular dynamics study of borole-alkyne cycloadditions revealing the dynamically accessible potential energy surface minimum structures, the kinetic product distributions, and the impact of substitution patterns.

This document is currently not available here.

Share

COinS
 
Nov 23rd, 10:45 AM Nov 23rd, 11:30 AM

Post-Transition State Bifurcations in Borole-Alkyne Cycloadditions

216

Unsaturated boron heterocycles have emerged as promising building blocks for functional materials in chemical sensing and organic electronics due to their interesting electronic structures. The five-membered borole ring is a four-electron antiaromatic system, isoelectric to the C5H5+ cyclopentadienyl cation. Antiaromatic destabilization renders boroles highly reactive toward cycloadditions and nucleophilic attacks at the tricoordinate boron atom. Experimental reactions of boroles and alkynes are often observed to yield different products (or mixtures thereof) depending on the nature of the substituents. In addition, many of the product structures are valence tautomers, and can interconvert via a web of thermally allowed pericyclic processes. Density functional theory (DFT) computations were performed in Gaussian 09 to study cycloadditions of both unsubstituted and substituted boroles and alkynes. Molecular geometries were optimized using the ωB97XD functional and the 6-31G(d) basis set. Quasi-classical molecular dynamics simulations were performed at the same level of theory. We report the first molecular dynamics study of borole-alkyne cycloadditions revealing the dynamically accessible potential energy surface minimum structures, the kinetic product distributions, and the impact of substitution patterns.