On-Surface Synthesis and Characterization of Triply Fused Porphyrin–Graphene Nanoribbon Hybrids

This is the peer reviewed version of the following article: Angewandte Chemie - International Edition 59. 3 (2020): 1334-1339, which has been published in final form at https://doi.org/10.1002/anie.201913024. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions
On-surface synthesis offers a versatile approach to prepare novel carbon-based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine-tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non-benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on-surface synthesis of a Por–GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por–GNR hybrid has been characterized by bond-resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV
Financial support from Spanish MICINN (CTQ2017‐85393‐P) is acknowledged. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV2016‐0686). This work was supported by the Swiss National Science Foundation (200020_182015, IZLCZ2_170184) and the NCCR MARVEL funded by the Swiss National Science Foundation (51NF40‐182892). Computational support from the Swiss Supercomputing Center (CSCS) under project ID s904 is gratefully acknowledged. Q.S. acknowledges the EMPAPOSTDOCS‐II programme under the Marie Sklodowska‐Curie grant agreement No 754364