Switchable (2 + 2) and (4 + 2) Cycloadditions on Boron Nitride Nanotubes under Oriented External Electric Fields: A...

Area of Science:

• * Materials Chemistry: Focuses on the chemical modification and functionalization of advanced materials.
• * Computational Chemistry: Utilizes theoretical methods to study reaction mechanisms and predict outcomes.

Background:

• * Cycloaddition reactions, specifically (2 + 2) and (4 + 2) types, are key for functionalizing nanocarbon and hexagonal boron nitride (hBN) materials.
• * Controlling these competing reactions with similar reactivity is challenging, limiting precise material derivatization.

Purpose of the Study:

• * To investigate the mechanism of oriented external electric field (OEEF)-modulated cycloadditions on zigzag boron nitride nanotubes.
• * To explore the selective control of competing (2 + 2) and (4 + 2) cycloaddition reactions using OEEFs.

Main Methods:

• * Mechanistic study employing computational chemistry to analyze reaction pathways.
• * Simulation of benzynes' cycloaddition reactions on pristine and substituted boron nitride nanotubes under OEEF.
• * Analysis of charge transfer dynamics and energy barriers in response to electric fields.

Main Results:

• * OEEFs exhibit opposing catalytic roles in (2 + 2) and (4 + 2) cycloaddition reactions due to distinct charge transfer directions.
• * The energy barriers of these reactions show different responses to electric fields applied along the nanotube axis.
• * Flipping the electric field vector allows for the reversal of catalytic or inhibitory effects, enabling selective reaction control.

Conclusions:

• * OEEFs provide a powerful tool for precisely controlling competing cycloaddition reactions on boron nitride nanotubes.
• * Selective synthesis of desired adducts can be achieved by manipulating the electric field vector.
• * This approach offers a novel strategy for the targeted functionalization of hexagonal boron nitride materials.