Polymerization of brominated aromatic compounds in a metal–organic framework for the bottom-up synthesis of graphene nanoribbons with either pyridinic or tertiary nitrogen

Abstract

Graphene nanoribbons (GNRs) have received considerable attention because of their width- and edge-shape-dependent bandgap tunability. Moreover, incorporating N into GNRs has been shown to change their optical, electronic, catalytic, and magnetic properties. Therefore, the large-scale synthesis of GNRs with controlled types and numbers of N-containing functional groups is needed. However, the mass synthesis of such GNRs is challenging because of the necessity of using metal substrates as catalysts and their subsequent removal. To address this, GNRs functionalized with either pyridinic N or tertiary N were synthesized by carbonizing brominated bicyclic aromatic compounds with pyridinic N in the nanospace of metal–organic frameworks (MOFs). The use of MOFs not only increased the yield of GNRs but also increased the percentage of either pyridinic N (from 38 to 51%, i.e. +13%) or tertiary N (from 9 to 35%, i.e. +26%). Results from X-ray photoelectron spectroscopy, infrared spectroscopy, and molecular dynamics simulations using a reactive force field suggested the presence of GNR-like structures with either pyridinic N or tertiary N in the samples synthesized at 673 K. This study offers valuable information for the mass synthesis of GNRs with either pyridinic N or tertiary N.