Polymorphic self-assembly of pyrazine-based tectons at the solution-solid interface.

Achintya Jana,Puneet Mishra,Neeladri Das

doi:10.3762/bjnano.10.50

Abstract

Exploring the surface self-assembly of small molecules that act as building blocks (tectons) for complex supramolecular structures is crucial for realizing surface-supported functional molecular devices. Here, we report on the synthesis and surface self-assembly of a new pyrazine-derived molecule with pyridine pendants. Ambient scanning tunneling microscopy investigation at the solution–solid interface reveals polymorphic self-assembly of these molecules on a HOPG substrate. Two different molecular packing structures with equal distribution are observed. Detailed analysis of the STM images emphasizes the crucial role of weak intermolecular hydrogen bonding, and molecule–substrate interactions in the formation of the observed polymorphs. Such weak hydrogen bonding interactions are highly desirable for the formation of modular supramolecular architectures since they can provide sufficiently robust molecular structures and also facilitate error correction.

Highlights

Molecular materials are attracting considerable attention for the fabrication of next-generation functional devices owing to their high density and low power requirements
The scanning tunneling microscopy (STM) experiments conducted under ambient conditions are prone to thermal drift and suffer from piezo creep and hysteresis
The acquired STM images were corrected by means of split-image technique [21] in which both the adsorbate layer and the substrate are recorded with molecular and atomic resolution, respectively, in a single frame

Summary

Introduction

Molecular materials are attracting considerable attention for the fabrication of next-generation functional devices owing to their high density and low power requirements. We report on the hydrogen bonding mediated selfassembly of newly synthesized pyrazine-derived molecules at the 1-phenyloctane–HOPG interface using scanning tunneling microscopy (STM) technique under ambient conditions. These molecules exhibit polymorphic self-assembly on the HOPG substrate where two different molecular packing structures with nearly equal distribution are observed.

Results

Conclusion