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The [n]cycloparaphenylenes ([n]CPPs)-n para-linked phenylenes that form a closed-loop-have attracted substantial attention due to their unique cyclic structure and highly effective para-conjugation leading to a myriad of fascinating electronic and optoelectronic properties. However, their strained topology prevents the π-extension of CPPs to convert them either into armchair nanobelts or planarized CPP macrocycles. Here we successfully tackle this long-standing challenge and present the bottom-up synthesis and characterization of atomically precise in-plane π-extended [12]CPP on Au(111) by low-temperature scanning probe microscopy and spectroscopy combined with density functional theory. The planar π-extended CPP is a nanographene with an all-armchair edge topology. The exclusive para-conjugation at the periphery yields delocalized electronic states and the planarization maximizes the overlap of p orbitals, which both reduce the bandgap compared to conventional CPPs. Calculations predict ring currents and global aromaticity in the doubly charged system. The intriguing planar ring topology and unique electronic properties make planar π-extended CPPs promising quantum materials.

Herein, we report a new method for synthesis of extended perylenes and terrylenes. The technique is based on the cascade dehydrative π-extensions (DPEX) of aryl aldehydes, in which stepwise annulations activate previously "dormant" substituents. Two- and fourfold cyclizations of 3-aryl-biphenyl-2,2'-dicarbaldehydes offer a rapid path to unsymmetrical perylenes and elusive terrylene derivatives, respectively. DPEX of 3,3''-(phenanthrene-1,8-diyl)bis (([1,1'-biphenyl]-2,2'-dicarbaldehyde)) leads to the biradical structure, which proceeds in situ into oxidative electrocyclization at room temperature. The described domino process complements and expands DPEX approach to a large family of fused acenes and related PAHs.

A novel catalyst‐free approach to benzoannulated oxygen‐containing heterocycles from fluorinated oligophenylenes is reported. Unlike existing methods, the presented reaction does not require an oxygen‐containing precursor and relies on an external oxygen source, potassium tert‐butoxide, which serves as an O2− synthon. The radical nature of the reaction facilitates nucleophilic substitution even in the presence of strong electron‐donating groups and enables de‐tert‐butylation required for the complete annulation. Also demonstrated is the applicability of the method to introduce five‐, six‐, and seven‐membered rings containing oxygen, whereas multiple annulations also open up a short synthetic path to ladder‐type O‐heteroacenes and oligodibenzofurans., O‐heteroacenes are now available by a one‐step LOOP reaction by SET‐induced SNAr‐radical de‐tert‐butylation‐SNAr. tBuOK serves as a reliable oxygen atom source and O2− synthon, enabling synthesis of dibenzofuran, benzoxanthenes, and benzooxepines, and a range of longer ladder‐type O‐heteroacenes from fluorinated oligophenylenes.

Caryl–F bond activation has become an important and quickly developing method for construction of carbon-based materials. We report that alumina-mediated C–F bond activation (AmCFA) enables construction of PAHs with zigzag periphery. This method includes formal Csp3–H activation and opens an avenue for generation of carbon-based nanomagnets directly on technologically relevant surfaces.

The synthesis of ten ortho-fused PAHs bearing boronic pinacol ester groups (BPin) is reported. The products are obtained via modification of Mallory photocyclization in 45–99% yields. Among them are examples of highly strained molecules such as [4]helicene derivatives with BPin substituents in the cavity. The method allows double C–C coupling and tolerates more than one BPin functionality.

We have discovered a dual (i. e., soft and hard) Lewis acidity of alumina that enables rapid one-pot π-extension through the activation of terminal alkynes followed by C-F activation. The tandem reaction introduces an acenaphthene fragment - an essential moiety of geodesic polyarenes. This reaction provides quick access to elusive non-alternant polyarenes such as π-extended buckybowls and helicenes through three-point annulation of the 1-(2-ethynyl-6-fluorophenyl)naphthalene moiety. The versatility of the developed method was demonstrated by the synthesis of unprecedented structural fragments of elusive geodesic graphene nanoribbons.

Pre-treated γ-alumina features reactive centers mimicking electronic interactions of propargyls with transition-metal-based catalysts. The combination of soft π-Lewis acidity and Brønsted basicity allows C-H propargyl activation under mild conditions.

Herein, we report a facile transition-metal-free approach to sulfur-containing heteroacenes from fluorinated oligophenylenes. Unlike most existing methods, the presented approach is not restricted to simple dibenzothiophene derivatives and thus appears to be a useful tool for the synthesis of extended sulfur-containing heteroacenes. The incorporation of sulfur is unambiguously preprogrammed via the positions of fluorines in the precursors, allowing the selective synthesis of extended thienoacenes with up to 96% yield.

The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3 activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.

Herein, we describe a facile synthesis of N-arylated carbazoles via ladderization of fluorinated oligophenylenes. The reaction consists of two subsequent nucleophilic substitutions triggered by an electronic transfer from dimsyl anions. The reaction allows the effective one-pot formation of at least six C–N bonds with pronounced selectivity to the C–F bond placement.

An unprecedented [6]helicene's cavity closure indicating the possibility of introducing seven-membered rings via alumina-mediated C–F activation is shown. This finding, in combination with a directed quadruple annulation of fluorinated oligoarylenes, opens a short pathway to elusive non-alternant PAHs. Starting with one fluorinated block, we have synthesized through a two-step procedure three new representatives with helical-, bowl- and saddle-shapes. Additionally, the structure–property relationship in these new PAHs is explored via theoretical, optical, and X-ray crystallographic studies.

Although a huge number of facile synthesis methods for nanoparticles (NPs) do exist, the products usually exhibit a distribution in particle size and shape. Thus, a separation step needs to be applied to adjust the particle properties according to the needs of the later application. Chromatography is a potentially scalable separation method which is well-established for separating molecules and promising for classifying NPs by size. Herein, we lay the foundations of particle chromatography by studying the separation of a C60/C70 fullerene mixture as well-defined particle probes using a pyrene-functionalized silica stationary phase. C60 fullerenes are perfect model particles as they are spherical, roughly 1 nm in diameter, interacting via van der Waals interactions only. First, we extract the Henry coefficients for C60 and C70 fullerenes from the elution behavior of the fullerene mixture. Using a particle-wall as well as particle-particle model for the van der Waals interaction potential, we determine the ...

Herein, we show that biradical character and appropriate distribution of spin density can be used for synthetic purposes. We demonstrate the rational domino annulation that includes dehydrative π-extension (DPEX) as the initiation step and subsequent oxidative electrocyclizations (EC) promoted by favorable localization of the unpaired electrons enabling up to four C-C bonds formed during the reaction. Contradicting to the Woodward-Hoffmann rules, the reaction proceeds at room temperature, whereas termination occurs when biradical character vanishes.

Herein, we present a modular approach to pristine angularly fused planar acenes. The approach includes the Pd-catalyzed fusion of several building blocks and implements a dehydrative π-extension (DPEX) reaction as a key step enabling facile access to diverse two-dimensional acenes. The scope was demonstrated on nine examples with up to quantitative yield.

Alumina‐mediated CF activation (AmCFA) is an established method to generate incipient phenyl cation (IPC) through polarization of C(aryl)F bonds. Herein, it is reported that AmCFA can be used to induce intramolecular arylation of aryl alkynes containing one, two, and three triple bonds. During the reaction, a single formally eliminated hydrogen fluoride (HF) leads to the formation of two, three, and four CC bonds, respectively. Thus, the transformation gives rapid access to π‐extension and serves as an interesting example of solid‐state rational domino annulation enabling the bottom‐up construction of nanographenes.

By exposure of α-fluorinated benzophenones to McMurry reaction conditions, we have observed the remarkable formation of 9,10-diphenylanthracene derivatives. This unexpected transformation necessitates the cleavage of the exceptionally stable aromatic C-F bond under mild McMurry conditions. In this work, the condensation of several related fluorinated benzo- and acetophenones has been investigated, which allow us to propose a domino-like fusion mechanism for this unusual transformation. The scope and limitations of the fluorine-promoted benzophenone fusion are subsequently discussed.

Large polycyclic aromatic hydrocarbons (PAHs) containing pentagons represent an important class of compounds that are considered to be superior materials in future nano-electronic applications. From this perspective, the development of synthetic approaches to large PAHs and nanographenes (NGs) is a matter of great importance. In this context indenoannulation appears to be the most practical way to introduce pentagons into NGs. Here we report that alumina-mediated C-F bond activation is an attractive tool for the synthesis of non-alternant NGs bearing several pentagons. The unique nature of the reaction leads to a rather counter-intuitive outcome and allows considering each previous aryl-aryl coupling as a promoter of the following one, despite the continuous increase in the strain energy. Thus, the presented strategy combines both facile synthesis and significant yields for large nonalternant PAHs and NGs.

The first experimental evidence that fullerenes react with alkali-metal trichloroacetates through a nucleophilic addition-substitution route, yielding dichloromethylenefullerenes as the final products, is reported. The intermediates, C60 (CCl3 )(-) and C70 (CCl3 )(-) anions, have been isolated in their protonated forms as ortho-C60 (CCl3 )H, as well as three ortho and one para isomer of C70 (CCl3 )H. The structures were unambiguously determined by means of (1) H, (13) C, and (1) H-(13) C HMBC NMR spectroscopy along with UV/Vis spectroscopy. The observed regiochemistry was analyzed with the aid of quantum chemical calculations. Conversion of the protonated compounds into the [6,6]-closed C60/70 (CCl2 ) cycloadducts under basic conditions can be effected only for the ortho isomers, whereas para-C70 (CCl3 )H decomposes back into pristine C70 .

The requirement to standardize measurement methods for BMD (Bulk Micro Defect) density and DZ (Denuded Zone) CZ silicon has lead to the establishment of a SEMI standard for annealed CZ silicon wafers. Therefore, it was decided that we should aim at standardizing the preferential-etching and 90-degrees laser- scattering tomography techniques as a collaborative work between JEITA (Japan Electronics and Information Technology Industries Association) and JSPS (Japan Society of Promotion of Science) 145th Committee. In this work, we carried out a set of round robin tests and examined whether we could jointly standardize both the preferential-etching and the 90 degrees laser-scattering methods. This resulted in a standardized measurement protocol for BMD density and DZ width, which has become known as the JEITA standard EM 3508 [1].

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