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In this contribution, seminal works in the area of photon‐ and charge‐management are highlighted with focus on covalent electron donor‐acceptor conjugates built around porphyrins (Ps), on one hand, and 0D, 1D, and 2D nanocarbons, on the other hand. Photons in these conjugates are managed by Ps, while 0D, 1D, and 2D nanocarbons serve as the active component, which enable managing charges. With a few leading examples, it can be explored much beyond the simple photon‐ and charge‐management characterization and emphasize photovoltaics and photocatalysis to convert and store energy. This contribution concludes by highlighting recent progress in mixing and matching the unique charge‐management features of nanocarbons in the design of multidimensional nanocarbons. [ABSTRACT FROM AUTHOR]

Synthesis and characterization of a series of rylene‐diimide substituted hexaphenylbenzenes (HPBs) is presented. The direct connection of the rylene‐diimide units to the HPBs via the imide‐N‐position without any linkers as well as the use of naphthalene‐diimides (NDIs) next to perylene‐diimides (PDIs) is unprecedented. While mono‐substituted products were obtained by imidization reactions with amino‐HPB and the respective rylene‐monoimides, key step for the formation of tri‐ and hexa‐substituted HPBs is the Co‐catalysed cyclotrimerization. Particular emphasis for physic‐chemical characterization was on to the number of NDIs/PDIs per HPB and the overall substitution patterns. Lastly, Scholl oxidation conditions were applied to all HPB systems to generate the corresponding hexa‐peri‐hexabenzocoronenes (HBCs). Importantly, the efficiency of the transformation strongly depends on the number of NDIs/PDIs. While three rylene‐diimide units already hinder the Scholl reaction, the successful synthesis of mono‐substituted HBCs is possible. [ABSTRACT FROM AUTHOR]

Abstract: Ein neuartiges π‐erweitertes “Superhelicen” auf der Basis von Hexa‐peri‐hexabenzocoronenen wurde mit einem effizienten vierstufigen Syntheseverfahren ausgehend von Diphenylether synthetisiert. Das Helicen wurde durch NMR‐Spektroskopie und Massenspektrometrie in Kombination mit Röntgenstrukturanalyse zweifelsfrei charakterisiert. Physikalisch‐chemische Analysen des Superhelicens und geeigneter HBC‐Referenzverbindungen enthüllen unter anderem die bemerkenswerten Fluoreszenzeigenschaften mit Quantenausbeuten Φf>80 %. [ABSTRACT FROM AUTHOR]

Abstract: A novel π‐extended “superhelicene” based on hexa‐peri‐hexabenzocoronenes (HBCs) has been synthesized by an efficient four‐step synthetic procedure starting from diphenyl ether. Comprehensive structural analysis of the helicene was performed by NMR spectroscopy and mass spectrometry measurements together with X‐ray analysis. Physicochemical analysis of the superhelicene and suitable HBC references revealed it had outstanding fluorescent features with quantum yields of over 80 %. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanodots (CNDs) were synthesized using low‐cost and biocompatible starting materials such as citric acid/urea, under microwave irradiation, and constant pressure conditions. The obtained pressure‐synthesized CNDs (pCNDs) were covalently modified with photo‐ and electroactive π‐extended tetrathiafulvalene (exTTF) by means of a two‐step esterification reaction, affording pCND‐exTTF. The electronic interactions between the pCNDs and exTTF were investigated in the ground and excited states. Ultrafast pump–probe experiments assisted in corroborating that charge separation governs the deactivation of photoexcited pCND‐exTTF. These size‐regular structures, as revealed by AFM, are stable electron donor–acceptor conjugates of interest for a better understanding of basic processes such as artificial photosynthesis, catalysis, and photovoltaics, involving readily available fluorescent nanodots. [ABSTRACT FROM AUTHOR]

Perylene- as well as naphthalenediimides were fused to hexabenzocoronenes (HBCs) at their imide position to realize highly π-extended donor-acceptor (D-A)-hybrids. Successful isomer separation in the first step was decisive to guarantee a straightforward synthetic sequence. Hexaphenylbenzenes as precursors were accessed via Diels-Alder reactions and reacted in a Scholl oxidation to yield the respective HBC derivatives. The fully conjugated benzimidazole linker, which separates the electron donating HBC from the electron accepting rylenediimide, enabled the formation of either a linear or a helical configuration. Largely different chemical, physical, and optoelectrical characteristics were noted for the two configurations. What stood out was their aggregation and their excited state deactivation depending on the solvent polarity. Results from global analysis of the femtosecond transient absorption data corroborated the formation of a charge-transfer (CT) state that is stabilized in the helically fused configuration relative to the linear analogue. However, a comparison with spectroelectrochemical experiments failed to disclose evidence for a charge-separated (CS) state., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Synthesis and characterization of a series of rylene-diimide substituted hexaphenylbenzenes (HPBs) is presented. The direct connection of the rylene-diimide units to the HPBs via the imide-N-position without any linkers as well as the use of naphthalene-diimides (NDIs) next to perylene-diimides (PDIs) is unprecedented. While mono-substituted products were obtained by imidization reactions with amino-HPB and the respective rylene-monoimides, key step for the formation of tri- and hexa-substituted HPBs is the Co-catalysed cyclotrimerization. Particular emphasis for physic-chemical characterization was on to the number of NDIs/PDIs per HPB and the overall substitution patterns. Lastly, Scholl oxidation conditions were applied to all HPB systems to generate the corresponding hexa-peri-hexabenzocoronenes (HBCs). Importantly, the efficiency of the transformation strongly depends on the number of NDIs/PDIs. While three rylene-diimide units already hinder the Scholl reaction, the successful synthesis of mono-substituted HBCs is possible., (© 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Single-molecule electronic components (SMECs) are envisioned as next-generation building blocks in quantum circuit systems. However, challenges such as the reproducibility of the electrode attachment to the individual molecules hamper their fundamental investigation. For our purpose, we introduced quasi optoelectronic electrodes (QOEs) that allow for rapid investigations of the properties and suitability of compounds for molecular electronic devices. In particular, we probed hexa-peri-hexabenzocoronene (HBC) as a model system for D 6h -symmetrical nanographenes, with porphyrins as QOEs attached to the periphery. We prepared selectively bis-porphyrin-functionalized HBCs with ortho-, meta- and para-substitution and studied their communication properties, in correlation to the geometrical alignment and size of the system, by electrochemistry and optical spectroscopy. Further insights into structure-property relationships were gained by DFT calculations and X-ray diffraction analysis., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon nanodots (CNDs) were synthesized using low-cost and biocompatible starting materials such as citric acid/urea, under microwave irradiation, and constant pressure conditions. The obtained pressure-synthesized CNDs (pCNDs) were covalently modified with photo- and electroactive π-extended tetrathiafulvalene (exTTF) by means of a two-step esterification reaction, affording pCND-exTTF. The electronic interactions between the pCNDs and exTTF were investigated in the ground and excited states. Ultrafast pump-probe experiments assisted in corroborating that charge separation governs the deactivation of photoexcited pCND-exTTF. These size-regular structures, as revealed by AFM, are stable electron donor-acceptor conjugates of interest for a better understanding of basic processes such as artificial photosynthesis, catalysis, and photovoltaics, involving readily available fluorescent nanodots., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)