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The photophysical and electrochemical properties of a fumaramide rotaxane stoppered with C(60) are reported. The results evidenced the strong binding interactions between the template and the macrocycle, which are also supported by molecular modelling.

Publisher Summary This chapter reviews the different synthetic methodologies for the covalent functionalization of fullerene along with the most examples in advanced materials-oriented applications. Fullerenes are polyhedral carbon cages in which sp 2 -carbons are directly bonded to three neighbors in an arrangement of five- and six-membered rings. C 60 has been the most extensively studied since its discovery because of its I h -symmetrical structure, and bulk production. The structure includes two different types of bonds, namely those at the junction of two hexagons, and those at the junction of a pentagon, and a hexagon. The measured bond lengths clearly show that the formal double bonds correspond to the 6–6 junctions, and thus there are no double bonds in the pentagons. The mean diameter of the sphere is ∼7.1 A. The van der Waals radius of the carbon atoms, the external diameter, is ∼10.4 A, whereas the inner diameter is ∼3.5 A. The crystal structure of C 60 revealed low-electron delocalization over the spherical surface, and the bond alternation clearly shows a preference for the resonance structure with the 30 double bonds localized at 6–6 junctions. The low delocalization is explained by considering the partial rehybridization of the sp 2 -C-atoms leading to a higher contribution from the s-orbitals. As a consequence, the double bonds are located exocyclic to the pentagons, providing radialene nature to the five membered rings, and 1,3,5-cyclohexatriene nature to the six-membered rings.

Electronic processes at the heterojunction between chemically different organic semiconductors are of special significance for devices such as light-emitting diodes (LEDs) and photovoltaic diodes. Here, we report the formation of an exciplex state at the heterojunction of an electron-transporting material, a functionalized hexaazatrinaphthylene, and a hole-transporting material, poly(9,9-dioctylfluorene-alt-N-(4-butylphenyl)diphenylamine) (TFB). The energetics of the exciplex state leads to a spectral shift of ∼1 eV between the exciton and the exciplex peak energies (at 2.58 eV and 1.58 eV, respectively). LEDs incorporating such bulk heterojunctions display complete quenching of the exciton luminescence, and a nearly pure near-infrared electroluminescence arising from the exciplex (at ∼1.52 eV) with >98% of the emission at wavelengths above 700 nm at any operational voltage.

Linear and ribbon-like polycyclic aromatic hydrocarbons such as acenes and graphene nanoribbons are at the forefront of current investigations, as these graphene "cut outs" possess discrete energy gaps that can be tailored with the number of rings and their arrangements. Pyrene-fused pyrazaacenes are a type of nitrogenated ribbon-like polycyclic aromatic hydrocarbons with a very high stability. As a matter of fact, ribbon-like pyrene-fused pyrazaacenes with as many as 85 linearly fused aromatic rings have been synthesised with thermal stabilities over 500 °C in air. This review covers most of the synthetic and application aspects of pyrene-fused pyrazaacenes from 1937 to our days, illustrating that pyrene-fused pyrazaacenes are a widely tuneable and a highly stable platform for developing ribbon-like nitrogenated polycyclic aromatic hydrocarbons for a broad spectrum of applications.

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A new strategy to obtain distorted pyrene-fused azaacenes is reported. The careful alignment and selection of substituents give rise to highly twisted pyrene-fused azaacenes. A combined global and local theoretical analysis shows how the strain is generated and dispersed across the aromatic backbone. Furthermore, simulation of the observed optoelectronic properties shines light on the structural factors that govern the properties of twisted pyrene- fused azaacenes.

Star-shaped nanographenes are large monodisperse polycyclic aromatic hydrocarbons that extend in size beyond the nanometer and have shown a lot of promise in a wide range of applications including electronics, energy conversion and sensing. Herein we report a new family of giant star-shaped N-doped nanographenes with diameters up to 6.5 nm. Furthermore, the high solubility of this SNG family in neutral organic solvents at room temperature allowed a complete structural, optoelectronic and electrochemical characterisation, which together with charge transport studies illustrate their n-type semiconducting character.

The synthesis of crystalline one-dimensional polymers provides a fundamental understanding about the structure??? property relationship in polymeric materials and allows the preparation of materials with enhanced thermal, mechanical, and conducting properties. However, the synthesis of crystalline one-dimensional polymers remains a challenge because polymers tend to adopt amorphous or semicrystalline phases. Herein, we report the synthesis of a crystalline one-dimensional polymer in solution by dynamic covalent chemistry. The structure of the polymer has been unambiguously confirmed by microcrystal electron diffraction that together with charge transport studies and theoretical calculations show how the ir-stacked chains of the polymer generate optimal channels for charge transport. This work was carried out with support from the Basque Science Foundation for Science (Ikerbasque) , POLYMAT, the University of the Basque Country, Diputaci?n de Guipu ? zcoa, Gobierno Vasco (PIBA_2022_1_0031 and BERC program) , Generalitat Valenciana (PROMETEU/2021/054) and Go- bierno de Espan ? a (Projects CEX2020-001067-M, PID2021- 124484OB-I00,PID2020-118117RB-I00 and CEX2019- 0 0 0 9 1 9-M financed by MCIN/AEI/10.13039/501100011033) . Project (PCI2022-132921) funded by the Agencia Estatal de Investigaci?n through the PCI 2022 and M- ERA.NET 2021 calls. Technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF) is acknowledged. This project has received funding from the European Research Council (ERC) under the European Union?s Horizon 2020 research and innovation program (Grant Agreement No. 722951 and 714122) . This project has received funding from the European Union?s Horizon 2020 research and innovation program under grant agreement No. 899895. This work was funded by the ? uropean Union under the Horizon Europe grant 101046231. This project has received support from the National Institutes of Health (R21GM135784) and the use of the Titan Krios within the Eyring Materials Center at Arizona State University (NSF DBI 1531991) . Support through project IF/00894/2015 and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PID- DAC) , is gratefully acknowledged. We thank the Nanoscale and Microscale Research Centre (nmRC) , University of Nottingham, for access to EM instrumentation. N.M.P. thanks La Caixa Foundation for a Postdoctoral Junior Leader - Retaining Fellowship (ID 100010434 and fellowship code LCF/BQ/PR20/11770014) .

[EN] A series of rhodium and iridium complexes with a N-heterocyclic carbene (NHC) ligand decorated with a perylene-diimide-pyrene moiety are described. Electrochemical studies reveal that the complexes can undergo two successive one-electron reduction events, associated to the reduction of the PDI moiety attached to the NHC ligand. The reduction of the ligand produces a significant increase on its electron-donating character, as observed from the infrared spectroelectrochemical studies. The rhodium complex was tested in the [3+2] cycloaddition of diphenylcyclopropenone and methylphenylacetylene, where it displayed a redox-switchable behavior. The neutral complex showed moderate activity, which was suppressed when the catalyst was reduced. We gratefully acknowledge financial support from the Ministerio de Ciencia y Universidades (PGC2018-093382-B-I00) and the Universitat Jaume I (UJI-B2021-39 and UJI-B2020-01). We are grateful to the Serveis Centrals d'Instrumentacio Cientifica (SCIC-UJI) for providing with spectroscopic facilities. This work was carried out with support from the Basque Science Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country, Diputacion Foral de Guipuzcoa, Gobierno Vasco (BERC programme) and Ministerio de Ciencia e Innovacion (Project CEX2020-001067-M financed by MCIN/ AEI/ 10.13039/501100011033). Technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF) are acknowledged. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 722951). This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 899895.

The chemical processing of low-dimensional carbon nanostructures is crucial for their integration in future devices. Here we apply a new methodology in atomically precise engineering by combining multistep solution synthesis of N-doped molecular graphene nanoribbons (GNRs) with mass-selected ultra-high vacuum electrospray controlled ion beam deposition on surfaces and real-space visualisation by scanning tunnelling microscopy. We demonstrate how this method yields solely a controllable amount of single, otherwise unsublimable, GNRs of 2.9 nm length on a planar Ag(111) surface. This methodology allows for further processing by employing on-surface synthesis protocols and exploiting the reactivity of the substrate. Following multiple chemical transformations, the GNRs provide reactive building blocks to form extended, metal-organic coordination polymers. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No. 946223 and No. 899895. Financial support was provided by the German Research Foundation (DFG) through the TUM International Graduate School of Science and Engineering (IGSSE), Excellence Cluster e-conversion, and the priority programme 1928 COORNETs, the China Scholarship Council (CSC) and the European Research Council (ERC) (no. 722951). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 722951). This work was carried out with support from the Basque Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country, Gobierno Vasco (BERC programme). Technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF) is acknowledged. Open Access funding enabled and organized by Projekt DEAL.