Issue 21, 2023

Reactivity variance between stereoisomers of saturated N-heterocyclic carbenes on gold surfaces

Abstract

Controlling the chirality of molecule-surface systems is essential for applications ranging from heterogeneous catalysis to biosensing. N-heterocyclic carbenes (NHCs) are quickly becoming a dominant ligand for noble metal surface passivation, but the potential of chiral NHC scaffolds remains untapped. In this work, two stereoisomers, one C2 symmetric and one Cs symmetric, of saturated N-heterocyclic carbenes (NHCs) and a structurally related unsaturated NHC (C2v symmetric) were synthesized as NHC-CO2 adducts. These CO2-protected NHCs were deposited on gold films and their presence on the films was confirmed by laser desorption ionization mass spectrometry (LDI-MS) and surface enhanced Raman spectroscopy (SERS). Surprisingly, the Cs NHC, but not the chiral C2 NHC, partially degrades to the independently synthesized unsaturated NHC upon binding to the gold. Theoretical calculations assist in explaining this phenomenon by showing that the NHCs primarily lie flat on the gold surfaces, which exposes the backbone protons on the Cs-symmetric NHC to a formal elimination of H2, while the C2-symmetric NHC remains protected from this elimination reaction. These results raise critical questions as to how the structure of NHC ligands may be tuned to influence binding and reactivity on gold surfaces.

Graphical abstract: Reactivity variance between stereoisomers of saturated N-heterocyclic carbenes on gold surfaces

Supplementary files

Article information

Article type
Research Article
Submitted
04 aug 2023
Accepted
18 sep 2023
First published
26 sep 2023
This article is Open Access
Creative Commons BY-NC license

Inorg. Chem. Front., 2023,10, 6282-6293

Reactivity variance between stereoisomers of saturated N-heterocyclic carbenes on gold surfaces

G. Kaur, N. L. Dominique, G. Hu, P. Nalaoh, R. L. Thimes, S. L. Strausser, L. Jensen, J. P. Camden and D. M. Jenkins, Inorg. Chem. Front., 2023, 10, 6282 DOI: 10.1039/D3QI01541F

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements