Molecular fluorophores based on N,C-chelate, four-coordinate organoborons exhibit tunable solid-state emission colors that cover the whole visible region from blue to red. The emission color can be tuned through the substituents on either quinolines or the boron center.

Oxidative intramolecular 1,2-amino-oxygenation reactions, combining gold(I)/gold(III) catalysis, is reported. The reaction provides efficient access to a structurally unique ionic pyridinium-oxazole dyad with tunable emission wavelengths. The application of these fluorophores as potential biomarkers has been investigated.

Heterogeneous photocatalysis is considered as an ecofriendly and sustainable approach for addressing energy and environmental persisting issues. Recently, heterogeneous photocatalysts based on covalent organic frameworks (COFs) have gained considerable attention due to their remarkable performance and recyclability in photocatalytic organic transformations, offering a prospective alternative to homogeneous photocatalysts based on precious metal/organic dyes. Herein, we report Hex-Aza-COF-3 as a metal-free, visible-light-activated, and reusable heterogeneous photocatalyst for the synthesis of 2,3-dihydrobenzofurans, as a pharmaceutically relevant structural motif, via the selective oxidative [3+2] cycloaddition of phenols with olefins. Moreover, we demonstrate the synthesis of natural products (±)-conocarpan and (±)-pterocarpin via the [3+2] cycloaddition reaction as an important step using Hex-Aza-COF-3 as a heterogeneous photocatalyst. Interestingly, the presence of phenazine and hexaazatriphenylene as rigid heterocyclic units in Hex-Aza-COF-3 strengthens the covalent linkages, enhances the absorption in the visible region, and narrows the energy band, leading to excellent activity, charge transport, stability, and recyclability in photocatalytic reactions, as evident from theoretical calculations and real-time information on ultrafast spectroscopic measurements.

A site-selective C-4/C-8 alkynylation of isoquinolones catalyzed by gold and rhodium complexes is reported. A broad range of synthetically useful functional groups (-F, -Cl, -Br, -CF3, -OMe, alkyl, etc.) were tolerated, providing an efficient and robust protocol for the synthesis either C-4- or C-8-alkynylated isoquinolones.

We report a series of tunable and persistent [4]-helicene neutral radicals by chemical reduction of the [4]-helicenium cation analogue. EPR spectroscopy and DFT calculations indicate that the unpaired electron is localized at the central carbon atom.

We report the reactivity between the Lewis acidic trioxatriangulenium ion (TOTA+) and a series of Lewis bases such as phosphines and N-heterocyclic carbene (NHC). The nature of the Lewis acid-base...

Reported herein, for the first time, is a copper-promoted intramolecular [4+2]-cycloaddition cascade to access ionic N-doped polycyclic aromatic hydrocarbons (PAHs) with tunable emission wavelengths.

The gold-catalyzed aminoalkynylation of alkynes for the synthesis of quinalizinones is reported. For instance, the reaction of pyridinoalkynes with 1-[(triisopropylsilyl)-ethynyl]-1,2-benziodoxol-3(1H)-one (TIPS-EBX) in the presence of a catalytic amount of AuCl at 50 °C afforded alkynylated quinalizinones in 57-87% yields.