A curved nitrogen-doped nanocarbon synthesized that can flip shape and trap a gold atom at its center

Molecular nanocarbons are critical bridges between small polycyclic aromatic hydrocarbons and extended graphene lattices, driving advances across materials science, optoelectronics, and quantum technologies. However, the atomically precise synthesis of such systems, particularly those featuring K-region and cove-type topologies, remains an enduring challenge. Here, we present a de novo modular strategy that overcomes this constraint by directing K-region growth via annulation of preorganized aryl acetylnaphthalene precursors with acetylenedicarboxylate. The strategy mirrors the hierarchical construction of pyrene by formally inserting naphthalene fragments into spatially defined molecular scaffolds. This method integrates Suzuki–Miyaura coupling with a Zn(OTf)2-catalyzed cascade comprising Friedel–Crafts alkylation, dehydro-Diels–Alder cycloaddition, and dehydrogenative aromatization. The platform affords structurally diverse pyrene-based molecular nanocarbons with programmable control over topology and dimensionality, spanning linear, contorted, and three-dimensional π-architectures. These results establish a generalizable blueprint for bottom-up synthesis of complex carbon-rich architectures with atomic precision.

Conjugated nanohoops have attracted much attention in recent years due to their unique optoelectronic properties. A more complex geometry, in which two nanohoops are covalently linked to form a so-cal...

Helical nanographenes are a fascinating class of π-extended chiral nanocarbons, where structural helicity imparts intrinsic chirality and unique optoelectronic properties to the rigid carbon framework. In this work, we synthesized a hexa-peri-hexabenzocoronene-based π-extended spiro-double carbo[7]helicene. The helical distortion of the structure was unambiguously confirmed by X-ray crystallography. The optical properties were explored through UV–Vis absorption, fluorescence, and phosphorescence measurements, complemented by density functional theory (DFT) calculations. Remarkably, the π-extended spiro-double carbo[7]helicene exhibited thermally activated delayed fluorescence (TADF) at room temperature and phosphorescence at low temperatures. Chiral HPLC successfully resolved the enantiomers into three fractions: (PP), (MM), and the meso forms (PM)/(MP), and chiroptical studies of the pure enantiomers revealed a moderately high glum value of 1.58 × 10–3. Finally, the origin of the observed dissymmetry factors was rationalized by analyzing the transition electric dipole moments (TEDM) and transition magnetic dipole moments (TMDM) derived from time-dependent density functional theory (TD-DFT) calculations.

Helicenes, chiral molecules with helical structures, are promising candidates for circularly polarized luminescence (CPL) materials. This review summarizes recent advances in red-to-NIR CPL-active he...

Indenofluorenes (IFs) have received great interest owing to their intrinsic antiaromaticity, open-shell diradical character, and narrow band gaps. Herein, we report the synthesis and comprehensive cha...

Three pyrene-embedded nanohoops with distinct molecular symmetries were synthesized. Symmetry engineering discretizes the tunneling pathways, yielding three stable conductance states at room temperat...

A puzzle in theoretical chemistry has been solved at TU Wien: A new computational method now makes it possible to calculate the forces between large molecules with unprecedented accuracy.

Extended π-conjugated systems are often insoluble, and their aggregation manner greatly affects their absorption spectra. This study produced a planar, soluble, and nonaggregated hexarylene-bisimide (HB) with appropriate substituents. The single-crystal X-ray structure of HB confirmed the planar molecular structure with small twist angles and the dimerization behavior of HB in the solid state. The concentration-dependent 1H NMR experiments in CDCl3 indicated that the association constant Kdimer is 4.6 × 103 M–1 at 298 K and ΔGdimer (298 K) = −20.8 kJ mol–1. The longest absorption of HB at the monomeric state exhibits a sharp and intense peak at 921 nm (ε = 230,000 M–1 cm–1, full width at half-maximum = 718 cm–1) in toluene. 75% of the absorption of HB above 400 nm appears in the near-infrared region, thus giving a practically colorless solution. Magnetic circular dichroism spectra of a series of oligorylene-bisimides reveal the predominant contribution of the linear polyene-like conjugation over the annulene-like conjugation for larger [n]oligorylene-bisimides.

Concealed non-Kekulé polybenzenoid hydrocarbons have no sublattice imbalance yet cannot be assigned a classical Kekulé structure, leading to an open-shell ground state with potential applications in o...

N-Doped molecular bowl/saddle hybrids were developed via core-expansion synthetic strategy. Owing to the structural features containing both positive and negative curvatures, these molecules exhibit ....

The increased mechanical flexibility, solution processability, ease of fabrication, and high Verdet constants have made organic Faraday rotators a promising alternative to conventional inorganic magneto-optical (MO) materials. Despite this, organic Faraday rotators have not been developed to address near-infrared (NIR) MO applications, limiting their device applications. Here, we describe a three-step synthesis and MO characterization of a fused octapyrrolyl cyclooctatetraene (FOPCOT) which exhibits a record high Verdet constant of a small molecule in the NIR-II region. Notably, the cyclooctatetraene core is constructed in a three-step one-pot reaction whereby a N,N′-dipyrrolyl acetylene is generated and immediately reacted with Rosenthal’s complex to produce the corresponding zirconacycle intermediate in situ. The cascade is completed with a copper-mediated transmetalation that reductively eliminates to yield the octapyrrolyl cyclooctatetraene. This transformation offers a distinct alternative to conventional methods for pyrrole incorporation into polycyclic aromatic hydrocarbons. Stoichiometric oxidation with AgPF6 affords the oxidized analogues FOPCOT•+ and FOPCOT2+, which display strong optical absorptions at 1743 and 1198 nm, respectively. Magnetic circular dichroism study on spin-coated thin films of FOPCOT2+ yielded a maximum Verdet constant of −2.5 × 105 deg T–1 m–1 at 1224 nm.

The first crystalline diradical dication [9]CPP2•2+ was successfully synthesized via an oxidation reaction under the support of weakly coordinating anion. Both experimental and theoretical analyses c...

Photoswitching molecules like the azoarenes have myriad potential applications, ranging from energy storage to targeted drug delivery. Upon irradiation, azoarenes convert from an E-form to a Z-form. T...

This review presents recent advances in the chemistry of expanded helicenes, defined as helicenes containing linearly fused benzene rings, as novel aromatic compounds. This review begins with a summa...

Cyclo[N]carbons, molecular rings consisting solely of N carbon atoms, have previously been studied in the gas phase and on surfaces at cryogenic temperatures, but they are generally considered too rea...

Two distorted nanographenes combining helicenes and a fluoranthene unit within their polycyclic scaffolds were synthesized. Their structural and electronic properties were elucidated by various spectr...

This study presents a molecular design strategy for bright NIR-II fluorophores by addressing fluorescence quenching and low absorption in aggregates. Through structural optimization of donor-acceptor...

A new class of curved, chiral polycyclic aromatic hydrocarbon emerges from the fusion of indeno[2,1-c]fluorene and quasi[8]circulene motifs. These redox-active, antiaromatic scaffolds offer great syn...

The synthesis and properties of a fused Koelsch radical derivative incorporating a seven-membered ring are described. The strategic incorporation of a heptagon into the extended π-system was hypothesi...

We synthesized a series of carbon nanohoops, [n]CPP-BODIPY (n = 6, 7, and 9), by embedding boron dipyrromethene (BODIPY) dye into cycloparaphenylene scaffolds. Due to the unique size effect and intra...

Silver-mediated phosphacyclic ring expansion with strategic placement of phosphorus and dimethyl acetylenedicarboxylate (DMAD) on Vat Orange 3 was carried out. The target compounds possess narrow HOMO...

Celebrating the molecule that changed the world

Chiral π-conjugated molecules hold great potential for applications in spin-selective organic semiconductors and chiroptical electronic devices that respond to circularly polarized light. Their perfor...

High quantum yields and dissymmetry factors are key to enhancing the chiroptical properties of [n]helicene-functionalized polycyclic aromatic hydrocarbons for the development of circularly polarized materials. In a two-step synthesis, a C2-symmetric perylene-embedded double [5]helicene was obtained through Suzuki–Miyaura cross-coupling and base-catalyzed condensation. With a configurational stability of 23 kcal mol–1, the short-lived enantiomers were separated using chiral HPLC. Compared to pristine [5]helicene, the compound shows enhanced (chir)optical properties with a quantum yield of 0.7, a gabs of up to 8.8 × 10–3, and a glum of 0.7 × 10–3.

Rylene diimides are among the most intensively researched classes of functional organic dyes. They are characterized by outstanding photoabsorption and -emission properties in combination with excellent photostability and thermal stability. Due to strong intermolecular π–π interactions, the larger, peri-extended rylene diimides, in particular, require the complex attachment of solubilizing substituents to enable their handling and processing in the solution phase. Herein, we introduce the diborinic imide functional group as a substitute for the commonly used dicarboximide moiety at the peri-termini of rylenes, thus leading to a new class of well-soluble rylene dyes with excellent optoelectronic properties. We synthesized borinic diimides of perylene (PDBI 5), terrylene (TDBI 7), and quaterrylene (QDBI 9) starting from a BNB-modified phenalenyl (1). These compounds show progressively bathochromically shifted absorption and emission characteristics with increasing system size, with fluorescence quantum yields up to ΦF = 0.92 for 5, and extended NIR (near-infrared) emission for 9. Single-crystal X-ray diffraction (XRD) studies reveal modified molecular packing in the solid state, pointing to a reduced tendency to aggregation. The new compounds undergo two reversible successive reductions, which were monitored by UV–vis–NIR spectroelectrochemistry. We performed the chemical reduction of 5 to obtain the potassium salts of the mono- and the dianion, K[5] and K2[5], respectively. Both the dianion and, in contrast to common rylene diimide dyes, also the monoanion show fluorescence emission, which extends into the NIR region. Quantum chemical ACID and 2D-NICSZZ calculations reveal a transition from mainly local aromaticity to global aromaticity upon reduction.

Azulene-fused molecular carbons have sparked intense research interest in recent years. Herein, we report a facile three-step synthesis of azuleno[1,2,3-cd]phenalene (AzPn), a fused system combining a...

Strategy enables efficient organic radical luminescence in solids by suppressing harmful interactions, aiding solid-state lighting

In a new study led by Oxford University's Department of Chemistry, chemists have demonstrated the synthesis of a cyclocarbon that is stable enough for spectroscopic characterization in solution at roo...