Comprehensive Summary:Two families of cyclopentadienyl (Cp)/carboranyl heteroleptic sandwiched organolanthanide complexes, namely [Ln{ η 5: σ-Me 2C(C 5H 4)(C 2B 10H 10)} 2][Li(DME) 3] ( 1Ln, Ln = Tb, Dy, Ho, Er) and [2-THF-2′-( µ 2-Cl)Li(THF) 3-2, 2′-Ln( nido-1, 7-C 2B 9H 11)Cp*] ( 2Dy), were synthesized. Family of 1Ln has been proposed based on the mixing-ligands idea by linking Cp and nido-dicarborllide. However, the carborane cage of [Me 2C(C 5H 4)(C 2B 10H 10)] 2− deprotons and forms a mono-C - anion rather than deboron to form dicarborllide dianion. Hence, the family of 1Ln features a dysprosocenium skeleton with extra two coordination of C - anions of carborllides. Such coordination geometry is more like a tetrahedron if abstracting the centroids of two coordinated Cp rings. In this cubic-type geometry, no significant magnetic axiality is presented; only 1Dy and 1Tb show field-induced slow magnetic relaxation behavior below 10 K. Inspired by 1Ln, the free pentamethylcyclopentadienyl (Cp* -) and nido-dicarborllide ligands are used to sandwich central Dy 3+ ion, achieving heteroleptic complex 2Dy. The bending angle by linking the centroid of Cp* -, Dy 3+ and C 2B 3 2− in 2Dy is increased to 132.8(1)°. As such, the effective energy barrier for magnetic reversal ( U eff) and magnetic blocking temperature T B (ZFC) are both increased ( U eff = 616(10) K; T B = 6 K). The effort of further enhancing U eff and T B in such heteroleptic organolanthanide sandwiches should rely on keeping increasing the ligand axiality.
Comprehensive Summary:Oil-in-oil nonaqueous emulsions are of great interest for developing emulsion-templated polymers and encapsulation systems that are incompatible with water-sensitive substances. Tailor-made amphiphilic block copolymers are by far the most efficient stabilizers for oil-in-oil emulsions while less attention is given to copolymers with more complex architectures. Here, we report the stabilization of DMSO-silicone oil interface by bottlebrush random copolymers (BRCPs) containing norbornene backbones with densely grafted poly(methyl methacrylate) (PMMA) and polystyrene (PS) side chains. The assembly kinetics of BRCPs at the DMSO-silicone oil interface can be divided into three processes, including diffusion, reconfiguration and reorganization, and can be varied by tuning the degree of polymerization of the backbone ( N B). Due to the high efficiency of BRCPs in reducing the interfacial tension, when using BRCPs as stabilizers, stable silicone oil-in-DMSO traditional emulsions and high internal phase emulsions (HIPEs) can be successfully obtained, while no stable emulsions can be achieved with linear PMMA- b-PS serving as the stabilizer. This study, for the first time, underscores the great potential of amphiphilic bottlebrush copolymers in preparing oil-in-oil emulsions. Given the advances in polymerization strategy, a broad variety of amphiphilic bottlebrush copolymers are expected to be synthesized and applied in the stabilization of nonaqueous biphasic systems.
Comprehensive Summary:Improving the catalytic efficiency and anti-poisoning ability of Pt-based catalysts is very critical in methanol electrolysis technology for high-purity hydrogen generation. Herein, the nitrogen-doped carbon polyhedrons-encapsulated MoP (MoP@NC) supported Pt nanoparticles were demonstrated to be effective for methanol electrolysis resulting from the combined advantages. The nitrogen-doped carbon polyhedrons not only greatly enhanced the conductivity but also effectively prevented the aggregation of MoP to offer Pt anchoring sites. The electronic structure modification of Pt from their interaction reduced the adsorption energy of CO*, resulting in good CO-poisoning resistance and accelerated reaction kinetics. Specifically, Pt-MoP@NC exhibited the highest peak current density of 106.4 mA·cm -2 for methanol oxidation and a lower overpotential of 28 mV at 10 mA·cm -2 for hydrogen evolution. Energy-saving hydrogen production from methanol electrolysis was demonstrated in the two-electrode systems assembled by Pt-MoP@NC which required a low cell voltage of 0.65 V to reach a kinetic current density of 10 mA·cm -2 on the glass carbon system, about 1.02 V less than that of water electrolysis.
Comprehensive Summary:The pursuit of sustainable and environmentally benign synthetic methods continues to challenge organic chemists. Herein, we introduce a magnetoredox system for tri- and difluoromethylation of isocyanides and N-arylacrylamides using a rotating magnetic field and steel rods. This magnetoredox approach enables facile synthesis of functionalized phenanthridines and oxindoles without the need for catalysts and additives under mild conditions. Such a system potentially represents an attractive strategy for selective formation of bonds through multifaceted regulation of magnetic intensity, rotating frequency, and rod size.
Comprehensive Summary:In on-surface synthesis, dimers are typically utilized to explore reaction mechanisms or as intermediates in the formation of final products. However, constructing the innovative nanostructures with dimers as building blocks remains challenging. Here, using non-planar 2, 2′, 7, 7′-tetrabromo-9, 9′-biflurenyliden molecules, we have successfully synthesized dimeric covalent organic frameworks (COFs) on the Au(111) surface through a temperature-controlled cascade reaction. Notably, the H-H steric hindrance within precursors caused by double bonds leads to selective stepwise debromination during the thermal annealing, which promotes the dimerization through intermolecular Ullmann coupling and cyclodehydrogenation reaction to form COFs primarily constituted by dimer building blocks. Combining scanning tunneling microscopy/spectroscopy and density functional theory calculations, we have precisely confirmed the structural evolution and reaction mechanism. Furthermore, by introducing Ag adatoms to form C−Ag−C intermediates, we have successfully regulated the reaction path and synthesized one-dimensional nanoribbons with dimers as building blocks. This work not only validates the strategy of synthesizing dimeric nanostructures on different surfaces through cascade reactions induced by precursor design, but also enriches the research field of surface synthesis of COFs and nanoribbons.
Comprehensive Summary:Traditional protecting groups are often removed under harsh conditions with potentially hazardous reagents, thereby impeding the convenient synthesis of oligosaccharides and glycosides. Herein, we present to utilize the photolabile ortho-nitro-benzyl carbonate ( oNBC) as a permanent hydroxyl protecting group for stereocontrolled synthesis of glycosides. The Ph 3PO-modulated glycosylation with strongly disarmed per- O- oNBC-protected glycosyl ynenoates preferred to afford glycosides with excellent α-selectivities via the β-phosphonium transition state. Based on the oNBC-mediated galactosylation, synthesis of the glycolipid digalactosyl diacylglycerol (DGDG) containing six double bonds and two esters was achieved in a straightforward manner.
Comprehensive Summary:Photodynamic therapy (PDT) has been attracted a surge of research interest. However, there are several obstacles to limit the efficacy of PDT, such as hypoxic tumor microenvironment (TME), overexpressed glutathione (GSH), inefficient reactive oxygen species (ROS) generation, and so on. Herein, a smart responsive nanosystem was constructed, which was composed of Au 25 modified with triphenylphosphine (Au 25-TPP), catalase (CAT) and GSH-responsive diselenide-bridged mesoporous silica nanoparticles (Se-MSN). When the nanosystem arrived at tumor site, Se-MSN was degraded by the intracellular overexpressed GSH to release Au 25-TPP and CAT. The Au 25-TPP was targeted to mitochondria and generated ROS under the 808 nm NIR laser irradiation to kill tumor cells. Simultaneously, CAT could catalyze hydrogen peroxide to provide oxygen for relieving the hypoxia of TME. Besides, GSH was consumed by the diselenide bond to diminish the ROS loss. The above tactics (mitochondria targeting, hypoxia relieving and GSH consuming) jointly enhanced the PDT efficacy. The nanosystem showed distinct in vitro anticancer effect significantly stronger than other groups containing one or two assistance. Moreover, the in vivo results suggested that the tumors could be restrained obviously. The current study provides a new inspiration for constructing novel inorganic nanomedicines with multiple enhancement effect of PDT efficacy.
Comprehensive Summary:Conjugate addition and allylic substitution are two essential chemical transformations, and they could be competitive for substrates with multiple reactive sites. Herein, we report the diversified enantioselective synthesis of cyclobutenes via the functionalization of cyclobutenones. The conjugate addition of cyclobutenones with arylzinc halides provided enantioenriched cyclobutenes with all-carbon quaternary centers. On the other hand, when cyclobutenones with gem-dichloro groups were employed, a chemo- and enantioselective allylic substitution occurred. Further synthetic utility was demonstrated for synthesizing versatile cyclobutane derivatives, together with ring-opening and expansion products.
Comprehensive Summary:A copper-catalyzed cyanation/diarylmethylation of formamides has been developed for the synthesis of α-cyano functionalized tetra-substituted olefins by utilizing para-quinone methides ( p-QMs) and trimethylcyanosilane as functionalization sources. Various kinds of p-QMs and formamides are well tolerated, delivering the desired products with 72%—94% yields, demonstrating broad functional group tolerance. Notably, the reaction does not require noble metals and proceeds regioselectively under mild conditions. Based on step-by-step control experiments, Hammett studies and DFT calculation, a plausible mechanism is proposed.
Comprehensive Summary:A tandem Diels–Alder reaction/Claisen rearrangement/decarboxylation strategy of N-allenamides (or aryloxyallenes) with 3-alkoxycarbonyl-2-pyrones has been developed for the efficient synthesis of diarylmethanes with moderate to good yields. The reaction exhibits good functional group tolerance and can be applied to late-stage modifications of known drug molecules. Mechanistic studies indicate that the ester group at the 3-position of 2-pyrones is essential, and the initial Diels–Alder reaction between the 2-pyrones and the proximal C=C bond of the N-allenamides (or aryloxyallenes) is crucial for the success of the reaction.
Comprehensive Summary:Amidst the pressing environmental challenges posed by the prevalent reliance on fossil fuels, it becomes imperative to seek sustainable alternatives and prioritize energy efficiency. Electrocatalysis, which is renowned for its high efficiency and environmental friendliness, has garnered significant attention. Rare earth elements (REEs), distinguished by their unique electronic and orbital structures, play a crucial role in electrocatalysis. The strategic integration of REEs into catalysts allows for the fine-tuning of atomic structures, which in turn, significantly boosts catalytic performance. Despite substantial advancements in rare earth-based materials for electrocatalysis, a comprehensive overview of the regulatory mechanisms involving REEs is lacking. In this mini-review, we systematically explore the regulatory mechanisms of REEs within electrocatalysts and their pivotal roles in essential electrocatalytic processes such as the CO 2 reduction reaction, oxygen reduction reaction, and hydrogen evolution reaction. We commence with an elucidation of REEs, proceed to delineate their regulatory impacts on electrocatalysts and delve into their applications in key electroreduction reactions. We conclude with discussions on current limitations and prospects for further advancements in this burgeoning field of research.
Comprehensive Summary: As a class of organic dyes, boron-containing compounds play an important role in organic luminescent materials. They have attracted considerable attention due to their unique photophysical properties. Chiral luminescent systems have a wide range of practical applications in biological imaging, optoelectronic devices, information storage and 3D display. Boron-containing chiral luminescent materials can not only effectively improve the luminescent properties of CPL materials, but also bring unique properties to the system, which enables them to be used as favorable CPL emitting materials for an expanded range of applications. Here, we review the research progress of boron-containing chiral luminescent materials by the detailed discuss according to different chiral skeletons, such as point chirality, 1, 1′-binaphthyl, [n]helicenes, [2, 2]paracyclophane and pillar[5]arenes. We believe that this review is of significance for the development of boron-containing compounds and CPL materials.
Key Scientists: The studies of circularly polarized luminescence (CPL) based on small organic molecules have advanced significantly. However, boron-containing chiral luminescent materials have gained attention only in recent years. In 2019, Zhao’s group prepared a binaphthalene derivative modified with triarylborane, representing the organic small molecule luminescent material to exhibit CPL characteristics responsive to both solvent and fluoride ions. In 2020, the Chen’s group used the unique luminescence properties and steric effects of triarylborane and triphenylamine to prepare CPL materials based on the planar chiral pillar[5]arenes. In 2021, Wang’s group developed a new class of B, N-embedded double hetero[7]helicenes molecules that exhibit strong chiroptical responses in the UV-visible region. In the same year, He’s group used asymmetric reactions to synthesize boron-based point-chirality compounds with high efficiency and enantioselectivity. In 2023, Ravat synthesized 1, 4-B, N-embedded helicenes exhibiting narrow-band fluorescence and CPL. During this period, Matthias Wagner et al obtained (BO)2-doped tetrathia[7]helicene via an efficient four-step synthesis, and Zheng reported the nearly pure green circularly polarized electroluminescent device (CP-OLED). In 2024, Chen’s group prepared B, N-embedded hetero-[9]helicenes offering a pathway towards significantly enhanced efficiency in helicene-based CPEL.