Youzhi

We report the synthesis and electron donor–acceptor features of a novel nanohybrid, in which the light-harvesting and electron-donating properties of a meso-tetraarylporphyrin (TArP) are combined with the electron-accepting features of nitrogen-doped carbon nanodots (NCNDs). In particular, in an ultrafast process (>10¹² s⁻¹), visible-light excitation transforms the strongly quenched porphyrin singlet excited states into short-lived (225 ps) charge-separated states. On the other hand, ultraviolet light excitation triggers a non-resolvable transduction of singlet excited state energy from the NCNDs to the porphyrins, followed by the same charge separation observed upon visible light excitation.

Antennas up! The synthesis and electron donor–acceptor features of a novel hybrid nanomaterial are reported. The nanohybrid combines the light-harvesting and electron-donating properties of a meso-tetraarylporphyrin (TArP) with the electron-accepting features of nitrogen-doped carbon nanodots (NCNDs).

In our search to cluster as many phenylene units as possible in a given space, we have proceeded to the three-dimensional world of benzene-based molecules by employing covalently interlocked cyclohexa-m-phenylenes, as present in the unique paddlewheel-shaped polyphenylene 10. A precursor was conceived, in which freely rotating m-chlorophenylene units provide sufficient solubility along with the necessary proximity for the final ring closure to give 10. Monitoring the assembly of solubilized tert-butyl derivatives of 10 into supramolecular carbon nanostructures by dynamic light scattering (DLS) and Brillouin light scattering (BLS) revealed the dimensions of the initially formed aggregates as well as the amorphous character of the solid state.

Essentially strain-free and thermally stable paddlewheel polyphenylenes consisting of two covalently interlocked cyclohexa-m-phenylenes have been synthesized. Tuning of the solubility allowed the hierarchical formation of three-dimensional carbon nanostructures to be monitored.

Bromination of [n]cycloparaphenylenes (CPPs) is herein reported. Small [n]CPPs (n<8) underwent a bis-bromine addition reaction with high site selectively to produce tetrabromo adducts in moderate to excellent yields. Theoretical calculations revealed that thermodynamic stability dictates both the reactivity and site selectivity of the reaction. The addition product was further converted into the octabromo product by a FeBr₃-catalyzed site-selective bromination reaction. The tetra- and octabromine adducts were then transformed into mono- to tetrabromo CPPs, which were further converted into several CPP derivatives. Therefore, bromination and subsequent transformations provide a path for late-stage functionalization of CPPs.

Pick a site: Small [n]CPPs (n<8) underwent a bis-bromine addition reaction with high site selectivity to produce tetrabromo adducts in moderate to excellent yields. The [5]CPP adduct was further converted into the octabromo product by a FeBr₃-catalyzed site-selective bromination reaction. The tetra- and octabromine adducts were then transformed into mono- to tetrabromo CPPs, which were further converted into several CPP derivatives. FG=functional group.

A homoditopic molecular host, janusarene, is presented that has two back-to-back compactly arranged nanocavities for guest complexation. The unique two-face structural feature of janusarene allows it to bind and align various guest compounds concurrently, which include spherical pristine fullerene C₆₀ and planar polycyclic aromatic hydrocarbons (PAHs), such as pyrene, perylene, and 9,10-dimethylanthracene. The host–guest interactions were characterized by single-crystal X-ray diffraction. A pairwise encapsulation of the PAH guests by janusarene enables PAH dimers to be obtained that deliver spectroscopic properties distinct from those of PAHs dissolved in solution, or in the bulk state. A monotopic control host was also synthesized and used to characterize the host–guest complexing behavior in solution.

Two-faced host: A back-to-back arranged homoditopic host compound, janusarene, is presented. The unique two-face structural feature of janusarene allows it to bind and align guest compounds that vary greatly in size and shape, such as spherical pristine fullerene and planar polycyclic aromatic hydrocarbons.

Numerous otherwise difficult applications have been realized with materials, the chemical/physical properties of which can be controlled by external stimuli such as heat, pressure, photo-irradiation, and voltage bias. However, the complexity of design and the lack of easy-to-conduct synthetic methods make the creation of on-demand stimuli responsive materials a formidable task. Here we report an electric-stimuli-responsive multifunctional material, [10]CPP-I: crystalline assembly of a hydrocarbon nanoring ([10]cycloparaphenylene: [10]CPP) as an “electro-responsive porous host” and iodine as a “potentially functional molecule”. Through applying electric stimulus, [10]CPP-I turned to exhibit two attractive properties: electronic conductivity and white light emission. We revealed that electric stimuli trigger the cascade formation of polyiodide chains inside the [10]CPP assembly through charge transfer, leading to the emergence of these properties. This “responsive porous host” approach is expected to be applicable for different stimuli, and opens the path for devising a generic strategy to the development of stimuli-responsive materials.

Host–guest systems: An electric-stimuli-responsive multifunctional material can be readily made by mixing a hydrocarbon nanoring ([10]cycloparaphenylene: [10]CPP) and iodine ([10]CPP-I). Through applying an electric stimulus, the assembled material [10]CPP-I is endowed with two attractive properties: turn-on electronic conductivity and white light emission.