Formation of Azulene‐Embedded Nanographene: Naphthalene to Azulene Rearrangement During the Scholl Reaction

Incorporation of a non‐hexagonal ring into a nanographene framework can lead to new electronic properties. During the attempted synthesis of naphthalene‐bridged double [6]helicene and heptagon‐containing nanographene by the Scholl reaction, an unexpected azulene‐embedded nanographene and its triflyloxylated product were obtained, as confirmed by X‐ray crystallographic analysis and 2D NMR spectroscopy. A 5/7/7/5 ring‐fused substructure containing two formal azulene units is formed, but only one of them shows an azulene‐like electronic structure. The formation of this unique structure is explained by arenium ion mediated 1,2‐phenyl migration and a naphthalene to azulene rearrangement reaction according to an in‐silico study. This report represents the first experimental example of the thermodynamically unfavorable naphthalene to azulene rearrangement and may lead to new azulene‐based molecular materials.     

Photocatalytic Conversion of Waste Plastics into C2 Fuels under Simulated Natural Environment Conditions

Reported here is the first highly selective conversion of various waste plastics into C₂ fuels under simulated natural environment conditions by a sequential photoinduced C?C cleavage and coupling pathway, where single‐use bags, disposable food containers, food wrap films, and their main components of polyethylene, polypropylene, and polyvinyl chloride can be photocatalytically transformed into CH₃COOH without using sacrificial agents. As an example, polyethylene is photodegraded 100 % into CO₂ within 40 h by single‐unit‐cell thick Nb₂O₅ layers, while the produced CO₂ is further photoreduced to CH₃COOH. Various methods and experiments disclose that O₂ and ^.OH radicals trigger the oxidative C?C cleavage of polyethylene to form CO₂, while other investigations show that the yielded CH₃COOH stems from CO₂ photoreduction by C?C coupling of ^.COOH intermediates. This two‐step plastic‐to‐fuel conversion may help to simultaneously address the white pollution crisis and harvest highly valuable multicarbon fuels in natural environments.     

New Radical Borylation Pathways for Organoboron Synthesis Enabled by Photoredox Catalysis

Radical borylation using N‐heterocyclic carbene (NHC)‐BH₃ complexes as boryl radical precursors has emerged as an important synthetic tool for organoboron assembly. However, the majority of reported methods are limited to reaction modes involving carbo‐ and/or hydroboration of specific alkenes and alkynes. Moreover, the generation of NHC‐boryl radicals relies principally on hydrogen atom abstraction with the aid of radical initiators. A distinct radical generation method is reported, as well as the reaction pathways of NHC‐boryl radicals enabled by photoredox catalysis. NHC‐boryl radicals are generated via a single‐electron oxidation and subsequently undergo cross‐coupling with the in‐situ‐generated radical anions to yield gem‐difluoroallylboronates. A photoredox‐catalyzed radical arylboration reaction of alkenes was achieved using cyanoarenes as arylating components from which elaborated organoborons were accessed. Mechanistic studies verified the oxidative formation of NHC‐boryl radicals through a single‐electron‐transfer pathway.     

Synthesis of Electron‐Deficient Corona[5]arenes and Their Selective Complexation with Dihydrogen Phosphate: Cooperative Effects of Anion–π Interactions

Reported here are the syntheses, conformational structures, electrochemical properties, and noncovalent anion binding of corona[5]arenes. A (3+2) fragment coupling reaction proceeded efficiently under mild reaction conditions to produce a number of novel heteroatom‐ and methylene‐bridged corona[3]arene[2]tetrazine macrocycles. Selective oxidation of the sulfur atom between two phenylene rings afforded sulfoxide‐ and sulfone‐linked corona[5]arenes in good yields. All corona[5]arenes synthesized adopted similar 1,2,4‐alternate conformational structures, forming pentagonal cavities. The cavity sizes and the electronic properties such as redox potentials, were measured with CV and DPV, and were influenced by the different bridging units. As electron‐deficient macrocycles, the acquired corona[3]arene[2]tetrazines served as highly selective hosts, forming complexes with the hydrogen‐bonded dimer of dihydrogen phosphate through cooperative anion–π interactions.     

Benzidine/Quinoidal‐Benzidine‐Linked,Superbenzene‐Based π‐Conjugated Chiral Macrocycles and Cyclophanes

Synthesis of fully conjugated cyclophanes containing large‐size polycyclic aromatics is challenging. Now, three benzidine‐linked, hexa‐peri‐hexabenzocoronene (superbenzene)‐based ortho‐, para‐, and meta‐cyclophanes are synthesized through intermolecular Yamamoto coupling reaction of structurally pre‐organized precursors. Subsequent oxidative dehydrogenation gave the corresponding quinoidal benzidine‐linked cyclophanes. Their geometries were confirmed by X‐ray crystallographic analysis and their electronic properties were investigated by electronic absorption, cyclic voltammetry, and DFT calculations. The quinoidal benzidine‐linked cyclophanes show thermally populated paramagnetic activity with a relatively large singlet‐triplet energy gap. Two enantiomers for the ortho‐cyclophanes ( 1‐NH and 1‐N ) were isolated and their chiral figure‐of‐eight macrocyclic structures were identified. The cage‐like cyclophanes 2‐NH and 3‐NH with concave surface can selectively encapsulate fullerene C₇₀.     

Full use of the liquid nature of the stationary phase: The development of elution‐extrusion counter current chromatography

Elution‐extrusion counter current chromatography extrudes the most solute retained in the column with the highest possible peak resolution. It can greatly improve the hydrophobic window. In recent years, elution‐extrusion counter current chromatography has received extensive attention in the separation of complex samples. This article first reviews the development and application of elution‐extrusion counter current chromatography, including its origin, mechanism, advantages and disadvantages, and some representative applications. At the same time, this review also shared our visions and ideas on how to improve the elution‐extrusion mode. This article aims to provide certain reference for the research of this technology.     

Room‐Temperature Ferroelectric Material Composed of a Two‐Dimensional Metal Halide Double Perovskite for X‐ray Detection

Although two‐dimensional (2D) metal–halide double perovskites display versatile physical properties due to their huge structural compatibility, room‐temperature ferroelectric behavior has not yet been reported for this fascinating family. Here, we designed a room‐temperature ferroelectric material composed of 2D halide double perovskites, (chloropropylammonium)₄AgBiBr₈, using an organic asymmetric dipolar ligand. It exhibits concrete ferroelectricity, including a Curie temperature of 305 K and a notable spontaneous polarization of ≈3.2 μC cm^?2, triggered by dynamic ordering of the organic cation and the tilting motion of heterometallic AgBr₆/BiBr₆ octahedra. Besides, the alternating array of inorganic perovskite sheets and organic cations endows large mobility‐lifetime product (μτ=1.0×10^?3 cm² V^?1) for detecting X‐ray photons, which is almost tenfold higher than that of CH₃NH₃PbI₃ wafers. As far as we know, this is the first study on an X‐ray‐sensitive ferroelectric material composed of 2D halide double perovskites. Our findings afford a promising platform for exploring new ferroelectric materials toward further device applications.     

Regulating Charge Transfer of Lattice Oxygen in Single‐Atom‐Doped Titania for Hydrogen Evolution

Single‐atom catalysts have attracted much attention. Reported herein is that regulating charge transfer of lattice oxygen atoms in serial single‐atom‐doped titania enables tunable hydrogen evolution reaction (HER) activity. First‐principles calculations disclose that the activity of lattice oxygen for the HER can be regularly promoted by substituting its nearest metal atom, and doping‐induced charge transfer plays an essential role. Besides, the realm of the charge transfer of the active site can be enlarged to the second nearest atom by creating oxygen vacancies, resulting in further optimization for the HER. Various single‐atom‐doped titania nanosheets were fabricated to validate the proposed model. Taking advantage of the localized charge transfer to the lattice atom is demonstrated to be feasible for realizing precise regulation of the electronic structures and thus catalytic activity of the nanosheets.     

Synergistic Dual‐Additive Electrolyte Enables Practical Lithium‐Metal Batteries

A rechargeable Li metal anode coupled with a high‐voltage cathode is a promising approach to high‐energy‐density batteries exceeding 300 Wh kg^?1. Reported here is an advanced dual‐additive electrolyte containing a unique solvation structure and it comprises a tris(pentafluorophenyl)borane additive and LiNO₃ in a carbonate‐based electrolyte. This system generates a robust outer Li₂O solid electrolyte interface and F‐ and B‐containing conformal cathode electrolyte interphase. The resulting stable ion transport kinetics enables excellent cycling of Li/LiNi_0.8Mn_0.1Co_0.1O₂ for 140 cycles with 80 % capacity retention under highly challenging conditions (≈295.1 Wh kg^?1 at cell‐level). The electrolyte also exhibits high cycling stability for a 4.6 V LiCoO₂ (160 cycles with 89.8 % capacity retention) cathode and 4.95 V LiNi_0.5Mn_1.5O₄ cathode.