Chemoselective Reactivity of Bifunctional Cyclooctynes on Si(001)

TL;DR

This study demonstrates a chemoselective method for functionalizing silicon surfaces using cyclooctyne, which reacts specifically via its strained triple bond, enabling targeted organic attachment crucial for semiconductor applications.

Contribution

The paper introduces a novel approach employing cyclooctyne to achieve selective silicon surface functionalization, overcoming challenges posed by silicon's high reactivity.

Findings

Cyclooctyne reacts selectively via its strained triple bond on Si(001).

Other organic groups react through metastable intermediates, reducing their reactivity.

The method enables targeted surface functionalization for semiconductor technology.

Abstract

Controlled organic functionalization of silicon surfaces as integral part of semiconductor technology offers new perspectives for a wide range of applications. The high reactivity of the silicon dangling bonds, however, presents a major hindrance for the first basic reaction step of such a functionalization, i.e., the chemoselective attachment of bifunctional organic molecules on the pristine silicon surface. We overcome this problem by employing cyclooctyne as the major building block of our strategy. Functionalized cyclooctynes are shown to react on Si(001) selectively via the strained cyclooctyne triple bond while leaving the side groups intact. The achieved selectivity originates from the distinctly different adsorption dynamics of the separate functionalities: A direct adsorption pathway is demonstrated for cyclooctyne as opposed to the vast majority of other organic functional groups. The latter ones react on Si(001) via a metastable intermediate which makes them effectively unreactive in competition with the direct pathway of cyclooctyne's strained triple bond.