Water dimer driven DNA base superstructure with mismatched hydrogen-bonding

TL;DR

This study visualizes individual water dimers within a DNA base layer on a metal surface, revealing their influence on local chirality and hydrogen-bonding patterns, advancing understanding of water cluster behavior at the molecular level.

Contribution

First real-space imaging of single water dimers embedded in a DNA base layer, showing their effect on surface chirality and hydrogen-bonding mismatches.

Findings

Water dimers cause local surface chiral inversion.

Hydration leads to heterochiral adenine molecules.

Theoretical simulations support experimental observations.

Abstract

The existence of water dimers in equilibrium water vapor at room temperature and their anomalous properties revealed by recent studies suggest the benchmark role of water dimer in both experiment and theory. However, there has been a limited observation of individual water dimers due to the challenge of water separation and generation at the single-molecule level. Here, we achieve real-space imaging of individual confined water dimers embedded inside self-assembled layer of a DNA base, adenine, on Ag(111). The hydration of the adenine layers by these water dimers causes a local surface chiral inversion in a way that the neighboring homochiral adenine molecules become heterochiral after hydration, resulting in a mismatched hydrogen-bond pattern between neighboring adenine molecules. Furthermore, the mutual influence between the adenine superstructure and these dynamic confined water dimers is corroborated by theoretical simulation and calculations. The observation of single confined water dimers offers an unprecedented approach to studying the fundamental forms of water clusters and their interaction with the local chemical environment.