showing 8 related works from this author
On-Surface Synthesis of Unsaturated Carbon Nanostructures with Regularly Fused Pentagon–Heptagon Pairs
2020
Multiple fused pentagon-heptagon pairs are frequently found as defects at the grain boundaries of the hexagonal graphene lattice and are suggested to have a fundamental influence on graphene-related materials. However, the construction of sp2-carbon skeletons with multiple regularly fused pentagon-heptagon pairs is challenging. In this work, we found that the pentagon-heptagon skeleton of azulene was rearranged during the thermal reaction of an azulene-incorporated organometallic polymer on Au(111). The resulting sp2-carbon frameworks were characterized by high-resolution scanning probe microscopy techniques and feature novel polycyclic architectures composed of multiple regularly fused pen…
Large-Cavity Coronoids with Different Inner and Outer Edge Structures
2020
Coronoids, polycyclic aromatic hydrocarbons with geometrically defined cavities, are promising model structures of porous graphene. Here, we report the on-surface synthesis of C168 and C140 coronoids, referred to as [6]- and [5]coronoid, respectively, using 5,9-dibromo-14-phenylbenzo[m]tetraphene as the precursor. These coronoids entail large cavities (>1 nm) with inner zigzag edges, distinct from their outer armchair edges. While [6]coronoid is planar, [5]coronoid is not. Low-temperature scanning tunneling microscopy/spectroscopy and noncontact atomic force microscopy unveil structural and electronic properties in accordance with those obtained from density functional theory calculation…
On-Surface Synthesis of Antiaromatic and Open-Shell Indeno[2,1- b ]fluorene Polymers and Their Lateral Fusion into Porous Ribbons
2019
Polycyclic hydrocarbons have received great attention due to their potential role in organic electronics and, for open-shell systems with unpaired electron densities, in spintronics and da-ta storage. However, the intrinsic instability of polyradical hydrocarbons severely limits de-tailed investigations of their electronic structure. Here, we report the on-surface synthesis of conjugated polymers consisting of indeno[2,1-b]fluorene units, which are antiaromatic and open-shell biradicaloids. The observed reaction products, which also include a non-benzenoid porous ribbon arising from lateral fusion of unprotected indeno[2,1-b]fluorene chains, have been characterized via low temperature scann…
Overcoming Steric Hindrance in Aryl‐Aryl Homocoupling via On‐Surface Copolymerization
2019
On-surface synthesis is a unique tool for growing low-dimensional carbon nanomaterials with precise structural control down to the atomic level. This novel approach relies on carefully designed precursor molecules, which are deposited on suitable substrates and activated to ultimately form the desired nanostructures. One of the most applied reactions to covalently interlink molecular precursors is dehalogenative aryl-aryl coupling. Despite the versatility of this approach, many unsuccessful attempts are also known, most of them associated to the poor capability of the activated precursors to couple to each other. Such failure is often related to the steric hindrance between reactants, which…
On-Surface Synthesis of Dibenzohexacenohexacene and Dibenzopentaphenoheptaphene
2021
We report the on-surface synthesis and gas-phase theoretical studies of two novel nanographenes, namely, dibenzohexacenohexacene and dibenzopentaphenoheptaphene, using 8,8′-dibromo-5,5′-bibenzo[rst]pentaphene as a precursor. These nanographenes display a combination of armchair and zigzag edges, as shown by noncontact atomic force microscopy (nc-AFM), and their electronic properties are elucidated by density functional theory (DFT) calculations which reveal relatively low HOMO-LUMO energy gaps of about 1.75 eV.
On-Surface Synthesis of Oligo(indenoindene)
2020
Fully conjugated ladder polymers (CLP) possess unique optical and electronic properties, and are considered promis-ing materials for applications in (opto)electronic devices. Poly(indenoindene) is a CLP consisting of an alternating array of five- and six-membered rings, which has remained elusive so far. Here, we report an on-surface synthesis of oligo(indenoindene) on Au(111). Its structure and a low elec-tronic bandgap have been elucidated by low-temperature scanning tunneling microscopy and spectroscopy and non-contact atomic force microscopy, complemented by density functional theory calculations. Achieving defect-free seg-ments of oligo(indenoindene) offers an exclusive insight into th…
CCDC 1980964: Experimental Crystal Structure Determination
2020
Related Article: Marco Di Giovannantonio, Qiang Chen, José I. Urgel, Pascal Ruffieux, Carlo A. Pignedoli, Akimitsu Narita, Klaus Müllen, Roman Fasel|2020|J.Am.Chem.Soc.|142|12925|doi:10.1021/jacs.0c05701
CCDC 1903872: Experimental Crystal Structure Determination
2019
Related Article: Marco Di Giovannantonio, Kristjan Eimre, Aliaksandr V. Yakutovich, Qiang Chen, Shantanu Mishra, José I. Urgel, Carlo A. Pignedoli, Pascal Ruffieux, Klaus Müllen, Akimitsu Narita, Roman Fasel|2019|J.Am.Chem.Soc.|141|12346|doi:10.1021/jacs.9b05335