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Dr. Rui Tang obtained her BSc degree in chemistry/chemical technology from a joint program between Sun Yat-Sen University and the Hong Kong Polytechnic University. She then got a MRes degree with distinction in catalysis from Imperial College London. After that, she was admitted to the joint PhD program offered by the University of Hong Kong and Southern University of Science and Technology under the supervision of Prof. Chi-Ming Che and Prof. Wei Lu. She completed her PhD degree at HKU in 2023. Now, she is a postdoctoral fellow in Prof. Che’s group at HKU.

Metal-metal-bonded excited states of Cu(I) complexes have rarely been studied, although such excited states of d¹⁰ noble metal complexes have been well documented to cleave C–H and C–X bonds. We describe here a panel of air-stable two-coordinate binuclear Cu₂(I,I) N-heterocyclic carbene complexes with short intramolecular Cu–Cu (2.75–2.88 Å) and Cu–arene (2.61–2.65 Å) distances. The triplet metal-metal-to-ligand charge transfer excited states of these Cu₂(I,I) complexes are highly emissive and long-lived (Φ_em up to 0.67, τ 2.9–36.1 μs in solution) and can cleave strong R–X (X = Br or Cl) bonds to give mixed-valence [X–Cu^1.5Cu^1.5–Y]^+/2+ (Y = X or solvent) species and carbon-centered radicals via an excited-state halogen-atom transfer mechanism. The spin-delocalized [X–Cu^1.5Cu^1.5–X]⁺ species (X = Br or Cl) have been characterized by single-crystal XRD, EPR spectroscopy, and density functional theory (DFT) calculations. Cu3 is an efficient photocatalyst for C–C coupling reactions with aryl/alkyl halides under 390 nm LED irradiation.

The self-assembly of metal-organic cages enables the rapid creation of atomically defined, three-dimensional, nanoscale architectures reminiscent of proteins. However, existing metal-organic cages are almost exclusively built from rigid and flat aromatic panels, limiting binding selectivity and, often, water solubility. Herein, we disclose a new class of cages—metal-peptidic cages—which utilize water-soluble, chiral, and helical oligoproline strands of varying lengths to generate highly anisotropic nanospaces. Further, we find that the formation of the cis isomer of the cage is strongly favored and is an emergent property of using complex and chiral building blocks in the formation of defined nanospaces. We demonstrate that the use of peptidic building blocks allows us to rapidly tune the size of the nanospace formed, from c. 1 to 4 nm, and that the use of biologically relevant components enables targeted binding of therapeutic molecules, highlighting the potential of these systems for selective drug delivery.

Mass production of Au–Cu-based catalysts with tailored selectivity is a complex and challenging task. We report a semi-affinity strategy to realize the synthesis of Au–Cu Janus nanocrystals with continuously tuned interfaces (from dimer, Janus, acorn-like Janus, to core-shell) based on Au nanosphere seeds. We highlight the role of interfacial strain due to a large lattice mismatch in growth control. The systematic electrochemical evaluation shows that the interfacial Cu oxide state, ∗CO coverage, and intermediate adsorption configuration can be well tuned by tailoring the Janus nanostructure. Optimized Au–Cu Janus catalyst reaches an efficiency of up to 80.0% for C₂₊ product with a partial current density of 466.1 mA cm⁻². The reaction products can be selectively switched from methanol (dimer) to ethanol (Janus) and further to ethylene (acorn-like Janus) by increasing the interface area of the Au–Cu heterostructures. The catalytic mechanisms are unraveled by operando surface-enhanced Raman spectroscopy (SERS) analysis and density functional theory calculations.

The synthesis of organochalcogenides remains a valuable area of research due to their widespread biological applications, particularly in pharmaceuticals. Herein, our study details the B(C₆F₅)₃-catalyzed Csp²–H functionalization of diverse arenes, heteroarenes, and pharmacophores with thiosuccinimides or selenosuccinimides, providing selective access to chalcogenated products. This protocol enables the selective late-stage chalcogenation of drug molecules such as the anti-inflammatory drug naproxen, the estrogen steroid hormone estradiol derivatives, and the industrially relevant trifluoromethylthiolation reaction. Furthermore, this C–S coupling methodology provides a facile and metal-free route to synthesize vortioxetine, an antidepressant drug, and a plethora of significant organic motifs. Detailed NMR, EPR analyses, and density functional theory (DFT) computational studies indicate that the elongation of the thiosuccinimide N–S bond is assisted by a boron-centered adduct, which then leads to a stable ion pair with an arene. The EPR analysis shows that a transient radical pair, potentially an off-cycle species, is not directly involved in the catalytic process.

Direct access to polyfunctionalized compounds by regioselective vicinal difunctionalizations of arenes is a challenging synthetic task that inspired the scientific community for years. The discovery of the Catellani reaction in 1997, a palladium-catalyzed vicinal difunctionalization reaction, was a real game-changer. This new paradigm offered various possibilities to access ortho/ipso-difunctionalized arenes and garnered attention over the years. From this pioneering work, innovative strategies have emerged. This perspective provides an overview of recent advances made in the field of catalytic vicinal arene difunctionalizations. It highlights current challenges and discusses future perspectives and opportunities.

Continuous flow reactions for the synthesis of block copolymers are a useful synthetic strategy because they provide better control over the polymerization reactions with easy scaling-up ability. Herein, a continuous flow system has been designed to combine two adverse polymerization processes, coordination-insertion using gaseous ethylene and free radical polymerization utilizing monomers of the acrylate family, to form polar polyethylene block copolymers. We demonstrate that a gas-liquid heterogeneous droplet flow system can lead to a successful living ethylene polymerization in which the gaseous component contains the reactive monomer. The addition of acrylates switches the reaction location to the liquid phase through the formation of a macroinitiator for the radical pathway and retarding the ethylene polymerization. We demonstrate that block copolymer segments can engage all phases of the droplet flow system and enable the synthesis of polar polyolefin block copolymers employing a single catalyst.

Complexation between two organic molecules can occur either for strong electron donor-acceptor pairs in the ground state, known as charge-transfer complexes (CTCs), or for pairs of lesser strength in the excited state, such as excimers and exciplexes. However, the characterization of chemically distinct CTCs in solution remains elusive. Here, we report a light-induced, solution-persistent 1:1 CTC between an amine and an imide. The pair is not associated in the ground state at room temperature prior to light exposure. The presence and exact molecular compositions of the CTCs could be directly obtained from high-resolution mass spectrometry. Additional spectroscopic and computational evidence reveal that a kinetically trapped ground-state pair is formed following an exciplex-like process between the amine and the imide after photoexcitation. We show that such a photoinduced complex can be used to conduct photochemistry and store photon energy for producing otherwise photochromic products in the dark.

Tim Cernak is an associate professor of Medicinal Chemistry at the University of Michigan. He holds appointments in the University of Michigan Department of Chemistry, Program in Chemical Biology, Center for Global Health Equity, and Michigan Institute for Data Science. Tim’s research interests include chemical synthesis, catalysis, total synthesis, cheminformatics, ecology, data science, automation, natural products, medicinal chemistry, agrichemistry, sustainability, cell imaging, mass spectrometry, conservation, robotics, extinction, and drug discovery. Tim has served on the advisory board of the University of Dundee’s Drug Discovery Unit, the Open Reaction Database, and Scorpion Therapeutics. He is a co-founder of Iambic Therapeutics.