Hybridisation at the organic-metal interface: a surface-scientific analogue of H\"uckel's rule?

TL;DR

This study shows that the conformation of cyclooctatetraene on noble-metal surfaces is influenced by hybridisation effects at the organic-metal interface, challenging the traditional charge transfer-based explanation linked to Hückel's rule.

Contribution

It provides a surface-scientific analysis demonstrating that conformational stabilization is driven by hybridisation, not charge transfer, offering a new perspective on molecule-surface interactions.

Findings

Conformations of COT vary on different noble-metal surfaces.

No significant charge transfer occurs during conformational changes.

Hybridisation at the interface is the key mechanism driving conformational stability.

Abstract

We demonstrate that cyclooctatetraene (COT) can be stabilised in different conformations when adsorbed on different noble-metal surfaces due to varying molecule-substrate interaction. While at first glance the behaviour seems to be in accordance with H\"uckel's rule, a theoretical analysis reveals no significant charge transfer. The driving mechanism for the conformational change is hybridisation at the organic-metal interface and does not necessitate any charge transfer.