Jiong Jia

Aggregation-induced emission enhancement of polycyclic aromatic alkaloid derivatives and the crucial role of excited-state proton-transfer

Aggregation-induced emission enhancement (AIEE) phenomenon is observed in the polycyclic aromatic alkaloid derivatives due to the configuration changes in the excited state, which is attributed to intramolecular proton-transfer and the formation of a new structure of enol form.

Three‐Dimensional Charge Transport in Organic Semiconductor Single Crystals

Three-dimensional charge transport anisotropy in organic semiconductor single crystals - both plates and rods (above and below, respectively, in the figure) - is measured in well-performing organic field-effect transistors for the first time. The results provide an excellent model for molecular design and device preparation that leads to good performance.

Gold/Lewis Acid Catalyzed Cycloisomerization/Diastereoselective [3 + 2] Cycloaddition Cascade: Synthesis of Diverse Nitrogen-Containing Spiro Heterocycles

A novel early and late transition-metal relay catalysis has been developed by combining a gold-catalyzed cycloisomerization and a Yb(OTf)3-catalyzed diastereoselective [3 + 2] cycloaddition with aziridines in a selective C-C bond cleavage mode. Various biologically significant complex nitrogen-containing spiro heterocycles were rapidly constructed from readily available starting materials under mild conditions.

Light-controlled self-assembly and conductance: from nanoribbons to nanospheres

Photoswitchable azobenzene (AZO) chromophores were introduced to the bay-position of the traditional n-type perylene diimide (PDI). Photocontrolled self-assembly behaviours and the influence of the azobenzene substitution on the assembly structure were investigated by UV/vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Controlled morphological evolution of the nanostructures from ribbons to spheres was facilely realized by driving the azobenzene switching unit with 365 nm light irradiation. The nanoribbons demonstrated highly ordered structures while the order of the molecular arrangement was destroyed in the nanospheres, as a result of the curved molecular conformation induced by photoisomerization. In addition, the conductivity of the single nanoribbon was investigated. Thanks to the one-dimensional long-range ordered π–π stacking of the PDI cores, the nanoribbon showed good semiconducting properties with a conductance in the range of 2 × 10−5 S m−1 in air. Furthermore, the conductivity decreased with UV light irradiation, mainly due to the increased randomness within the nanostructures, representing the light-induced switching of conductance in the supramolecular systems that is extremely interesting for molecular devices.

Intramolecular H⋯H steric hindrance modulated aggregate packing and optoelectronic properties in 1-naphthyl, 9-anthryl end-capped styrylarylene derivatives

The crystal structures and optoelectronic properties of the compounds 1,4-bis[2-(1-naphthyl)vinyl]benzene (BNVB), 4,4′-bis[2-(1-naphthyl)vinyl]biphenyl (BNVBP) and 4,4′-bis[2-(9-anthryl)vinyl]biphenyl (BAVBP) were studied and compared. Due to intramolecular H⋯H steric hindrance, BAVBP molecules adopt a twisted conformation and constructed into a three-dimensional C–H⋯π interacting structure. In contrast, the H⋯H steric hindrance is alleviated in compounds BNVB and BNVBP. Both molecules have much better planar character and aggregate into a lamellar structure with a herringbone packing motif. The aggregate structure exerts a dramatic influence on the optoelectronic properties. Compound BAVBP shows an aggregation-induced enhanced emission (AIEE) character. While, both BNVB and BNVBP are AIEE-inactive, BNVBP displays moderate hole-transporting ability.

Synthesis of Spiroketals by Synergistic Gold and Scandium Catalysis

An ultrafast synthesis of spiroketals by synergistic gold(I) and Sc(III) catalysis has been reported. Diverse 5,6-benzannulated spiroketals were rapidly constructed by the diastereoselective [4 + 2] cycloaddition between gold-generated enol ether and Sc(III)-catalyzed o-quinone methide intermediates. Ultrafast reaction rate, ambient reaction temperature, general scope, high yields, excellent diastereoselectivity, and good scalability are attractive features of this method.

A tandem coupling/smiles rearrangement/cyclization approach to 1,4-benzooxazinones or 1,4-pyridooxazinones under mild conditions

A facile and efficient approach to 1,4-benzooxazinone or 1,4-pyridooxazinone scaffolds is developed via Smiles rearrangement tandem reaction. 1,4-Benzooxazinones or 1,4-pyridooxazinones with diversity at two substituents on their scaffolds were synthesized conveniently in the presence of cesium carbonate at room temperature in good to excellent yields. The reaction mechanism is assumed by a tandem coupling/Smiles rearrangement/cyclization process.