Room temperature self-assembly of cation-free guanine quartet network nucleated from Mo-induced defect on decorated Au(111) with graphene nanoribbons

TL;DR

This study demonstrates room temperature self-assembly of extensive cation-free guanine quartet networks on Au(111), nucleated by Mo-induced defects and stabilized by graphene nanoribbons, confirmed through STM/STS and DFT analyses.

Contribution

It introduces a novel method for forming stable, cation-free guanine quadruplex networks at room temperature on gold surfaces, expanding potential applications.

Findings

Cation-free GQ networks can be self-assembled at room temperature.

Mo-induced defects serve as nucleation sites for GQ formation.

Graphene nanoribbons enhance network extent and stability.

Abstract

Guanine-quadruplex, consisting of several stacked guanine-quartets (GQs), has emerged as an important category of novel molecular targets with applications from nanoelectronic devices to anticancer drugs. Incorporation of metal cations into GQ structure is utilized to form stable G-quadruplexes, while no other passage has been reported yet. Here we report the room temperature (RT) molecular self-assembly of extensive metal-free GQ networks on Au(111) surface. Surface defect induced by an implanted molybdenum atom within Au(111) surface is used to nucleate and stabilize the cation-free GQ network. Additionally, the decorated Au(111) surface with 7-armchair graphene nanoribbons (7-AGNRs) results in more extensive GQ networks by curing the disordered phase nucleated from Au step edges spatially and chemically. Scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT) calculations confirm GQ networks' formation and unravel the nucleation and growth mechanism. This method stimulates cation-free G-quartet network formation at RT and can lead to stabilizing new emerging molecular self-assembly.