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Cyclooctatetraene (COT) and COT²⁻ dianion are well-known as archetypical non-aromatic and aromatic systems, respectively. However, despite a wealth of studies the effect of one electron addition to the eight-membered ring remains equivocal. Herein, we report the first stepwise electron addition to tetrabenzo[a,c,e,g]cyclooctatetraene (TBCOT or tetraphenylene), accompanied by isolation and structural characterization of the mono- and doubly-reduced anions. The X-ray crystallographic study reveals only a small asymmetric distortion of the saddle-shaped core upon one electron uptake. In contrast, the doubly-reduced product exhibits a severely twisted conformation, with a new C−C bond separating the COT ring into two fused 5-membered rings. The reversibility of the two-fold reduction and bond rearrangement is demonstrated by NMR spectroscopy. In agreement with experimental results, computational analysis confirms that the reduction-induced core rearrangement requires the addition of the second electron.

The uneven growth of lithium dendrites not only compromise the performance of lithium metal batteries, but also has security risks. In this sutudy, double coating with MgF₂ and hydroxypropyl methylcellulose was synthesized on the surface of polyethylene separator through a simple soaking and in-situ chemical precipitation method, achieve the purpose of protecting lithium metal anode. Utilizing the MgF₂/HPMC@PE separator, the Li||Li symmetric cell was capable of cycling for over 1000 hours with a voltage hysteresis of only 11.4 mV, comparing the voltage hysteresis based on the cell use of PE separator increases rapidly after 200 h. Furthermore, the initial discharge capacity of Li||LiNi_0.6Co_0.2Mn_0.2O₂(NCM622) is 144.6 mAh g⁻¹ and the capacity retention is 87.2 % after 200 cycles at 1 C, which is higher than that of the PE separator (135.3 mAh g⁻¹, with retention of 74.9 %). All improvements can be credited with the formation of stable solid electrolyte interphase(SEI) film induced by HPMC/MgF₂ double coating, which is reduced the Li nucleation overpotential and ultimately promoted uniform Li deposition. This study provides a simple and effective strategy for improving the cycling performance and safety of lithium metal batteries.

In the growing field of peptidomimetics, there is a constant need for new synthetic methods to generate new bioactive compounds. Herein, we present an atom-economic approach for the branched-selective allylation of aliphatic amine moieties of α-amino acids and small oligopeptides. This Rh-catalyzed hydroamination of allenes with a commercially available ligand forms a new stereocenter, often chemoselectively, in a catalyst-controlled manner, providing high yields and stereoselectivities without the need for an additive. The method is shown to be effective in gram scale without the need for column chromatography for purification, and ready-to-use allylated substrates for solid-phase peptide synthesis can be synthesized in two steps from the products of the catalysis.

Herein, we describe the trifluoro- and difluoroethoxylation of C(sp²)-H bonds using nickel(II) complexes incorporating a model macrocyclic arene substrate. Due to the coordinative properties of the macrocyclic substrate, we were able to detect and characterize the just-formed C(sp²)−OCH₂CF₃−Ni(II) species by HRMS and IRPD. DFT studies on the C(sp²)−OCH₂CF₃ bond formation mechanism indicate that it involves a Ni(III)/Ni(I) reductive elimination followed by oxidation to Ni(II) rather than the higher energy barrier Ni(IV)/Ni(II) reductive elimination. This mechanistic investigation deepens the versatile redox abilities of Ni compounds and might help in designing new catalysts for the 2,2,2-trifluoroethoxylation and 2,2-difluoroethoxylation of arene C−H bonds.

Dynamic-covalent electrophiles called cascade exchangers (CAXs) can reversibly engage cell-surface thiols. Conjugates between CAXs and molecular or even protein-sized cargos can deliver these cargos into cells by thiol-mediated uptake (TMU); free CAXs can also hinder TMU presumably by competing for thiol exchange sites. So far, three orthogonal networks of cellular thiol exchange partners have been identified to participate in TMU, centering on the transferrin receptor, integrins, and protein disulfide isomerases. This study introduces cyclic selenenylsulfides as a new CAX type, with polarised reactivity that brings important differences from the known disulfide and diselenide CAXs. Additionally, this study introduces methods to modulate CAX activity by employing remote functional groups to tune ring re-closure rates, e. g. via thiolate de/stabilization by hydrogen bonding and ion pairing. Differently to all CAXs known, Se-centred CAXs participate in two different TMU networks (integrins preferred, PDIA3 tolerated). When free, the remotely tuned Se-centred CAXs were strong inhibitors of most TMU systems, but again brought a novel feature: they increased the uptake of tetrel-centred Michael acceptor CAXs, making them the first free CAX we know of that can accelerate TMU. We conclude that Se- and tetrel-centred CAXs share a cellular thiol exchange partner that hinders TMU, which may be a target for improving the delivery of Michael acceptor drugs. The unique thiol exchange partner patterns generated by Se-centered CAXs with remotely tuned ring closure motifs support that they will prove a valuable tool to help decode TMU and achieve chemical control over cellular entry on the molecular level.

There has been a plethora of experience in conducting organic reactions in solution, with little to no knowledge in organic reactions on surfaces. Broadening the horizon of organic on-surface synthesis will enable creation of functional materials and direct integration into devices. Herein, we report an Ullmann reaction on thiol-functionalized gold nanoparticles serving as reactant, stabilizing agent, catalyst and reducing agent in this transformation. The orientation of ligands and formation of Surface Assembled Monolayer (SAM) on the gold nanoparticles were exploited to attain selectivity of hetero- over homo-Ullmann coupling, thus, expanding the toolbox of organic on-surface synthesis to nanoparticles.

A tryptophan modification that utilizes S-acetamidomethyl cysteine sulfoxide under mildly acidic conditions with magnesium chloride was achieved. An optimum condition in an ionic liquid allowed antibody modification without significant denaturation. In their Research Article, A. Otaka and co-workers describe the difference in chemical behaviors to acids between S-acetamidomethyl and p-methoxybenzyl cysteine sulfoxides permitted peptide heterodimerization in a one-pot sequential manner.

The ignited meteorite serves as a vivid representation of a carbon atom. Upon collision with the molecule, the meteorite merges with it, and the eruption of flames soaring in tetrahedral direction signifies the formation of four novel covalent bonds realized by the single-carbon-atom doping (SCAD) reaction, which is the focus of this Concept article by H. Fujimoto and M. Tobisu.

The cover illustrates the usefulness of the Group 13 ylide-based amphiphiles, also known as hidden frustrated Lewis pairs (FLP), towards the facile activation of σ-E−H bonds. In their Research Article, F. Breher, I. Fernández and co-workers computationally explored the factors controlling the activation of sigma bonds promoted by hidden FLP using quantum chemical tools.

A Cu@Cr₂O₃/TiO₂ plasmonic photocatalyst together with charge separation of hot electrons and positive holes working under visible light irradiation is depicted on the cover feature. In their Research Article, H. Kominami and co-workers report that part of Cr₂O₃ (red and turquoise spheres) has been removed from the Cu@Cr₂O₃/TiO₂ core–shell particle in the center to show the inner Cu nanoparticles (orange spheres). The hot electrons (e⁻) generated by the light irradiation move to the surface of the TiO₂, and the positive holes (h⁺) are left on the Cu@Cr₂O₃/TiO₂ particle.