Magnesium hydride (MgH2) suffers from sluggish dehydrogenation kinetics owing to its strong Mg-H bonding, which limits its practical application. In this work, we present a systematic density functional theory (DFT) and climbing-image nudged elastic band (CI-NEB) study on the adsorption and dissociation behavior of MgH2 on rare-earth (RE = Ce, La, Sm, Y) doped TiO2(001) surfaces, with particular focus on the regulatory effects of doping configuration (substitutional vs. interstitial) and RE identity. Both doping modes are found to enhance surface charge transfer capability by introducing localized impurity states and narrowing the band gap. Beyond the conventional Mg-O charge transfer pathway, an additional RE-H coupling channel is identified, which plays a crucial role in stabilizing the adsorption configuration and weakening the Mg-H bonds, although its contribution varies with doping mode and RE element. More interestingly, the catalytic behavior differs markedly across dopants: on substitutionally doped surfaces, Ce, La, and Sm promote molecular adsorption of MgH2, whereas Y induces spontaneous and complete dissociative adsorption. On interstitially doped surfaces, Y and Sm lead to semi-dissociative adsorption of MgH2. Taking Ce doping as a representative case, the dehydrogenation energy barrier is substantially reduced from 0.48 eV on pristine TiO2 to approximately 0.13-0.15 eV. This study elucidates the atomic-scale catalytic enhancement mechanism of RE-doped TiO2 and provides a new perspective for the rational design of high-efficiency, low-cost RE-based hydrogen storage catalysts.

Abstract Dearomative photocycloaddition reactions of (hetero)arenes offer a powerful route to three-dimensional molecular scaffolds with high value in medicinal chemistry. Summarized here are recent progress on strain-release accelerated dearomative photocycloaddition with bicyclo[1.1.0]butanes and highly regio- and enantioselective [2 + 2] cycloadditions of quinolines and indole derivatives. Key to the success of the reaction is the strategic design of chiral N,N′-dioxide/metal Lewis acid catalysts with tailored steric bulk that can modulate the chiral pocket to adapt to the varied electronic and steric characteristics of different substrate substituents. The catalyst’s role and the origin of stereoselectivities were elucidated based on experimental studies and theoretical calculation.

Catalytic dearomative photocycloaddition stands as one of the most powerful strategies for constructing highly complex, three-dimensional polycyclic scaffolds from readily accessible planar aromatic precursors. However, achieving asymmetric variants of these transformations with simple alkenes remains a formidable challenge, as it demands precise control over regio-, diastereo-, and enantioselectivity. Herein, we report asymmetric dearomatizing [2 + 2] and [4 + 2] photocycloadditions of 2-naphthalene derivatives by chiral terbium(III)/N,N'-dioxide complexes, wherein a pronounced ligand-acceleration effect is operative. The selectivity between the two pathways is governed by reaction temperature, alkene stoichiometry, and reaction time, thereby enabling the divergent synthesis of chiral cyclobutane-fused adducts (46 examples, up to 99% yield, > 19:1 dr, 99% ee) and bridged adducts (41 examples, up to 99% yield, up to 12:1 dr, 99% ee) with high efficiency. Notably, both cycloaddition manifolds accommodate terminal and internal olefins. Mechanistic investigations elucidate the origin of the ligand-acceleration effect and establish a kinetic basis for ortho-selectivity in the [2 + 2] pathway and a thermodynamic basis for para-selectivity in the [4 + 2] pathway. Density functional theory calculations further rationalize the competitive interplay between [2 + 2] and [4 + 2] cycloadditions and provide insight into the stereochemical outcome.

ABSTRACT Catalytic C─H alkylation of pyrazoles with internal alkenes represents an ideal strategy for constructing functionalized pyrazoles. However, such a transformation has remained underexplored to date, likely due to the inherently low reactivity of internal alkenes and the lack of suitable catalysts. In this study, we describe a lanthanum‐catalyzed highly regioselective C─H alkylation of N ‐aryl pyrazoles with internal alkenes. The key to success of this unprecedented transformation is the use of a cationic imidazolin‐2‐iminato lanthanum catalyst, whose large ionic radius and less steric hindrance provide an open coordination environment that facilitates the coordination of sterically demanding internal alkenes to the metal center and subsequent alkene migratory insertion. Besides internal alkenes, 1,1‐disubstituted styrenes and terminal alkenes were amenable to the reaction. This protocol offers a straightforward and atom‐efficient route for the synthesis of a new family of N ‐(( ortho‐ alkyl)aryl) pyrazole derivatives (94 examples, up to 99% yield, >19:1 rr). The scale‐up synthesis and further transformation to hedgehog enzyme inhibitor analog highlight the potential application of this method. Combined experimental and computational studies elucidated the reaction mechanism and the influence of metal ion size on the turnover‐limiting alkene migratory insertion step.

A highly diastereo- and enantioselective dearomative Diels-Alder reaction was accomplished by chiral N,N'-dioxide/Mg(II) complex catalyst. Various anthracene derivatives and methyleneindolinones efficiently transformed into the corresponding chiral spiro-bridged cyclic products with four consecutive stereocenters in good yields, excellent dr and er values under mild conditions (46 examples, up to 99% yield, >19:1 dr, >99:1 er). Gram-scale synthesis of chiral products and their further transformations were feasible. On the basis of theoretical calculation, possible working modes were provided to understand the origin of stereoselectivity of this transformation.

Chiral γ-hydroxy-γ-lactams were versatile building blocks for the synthesis of many important bioactive compounds. Herein, we disclosed a regio- and enantioselective direct α-selective allylation of amide moiety of maleimides with...

The oxidative cross-dehydrogenative coupling (CDC) via alpha-carbonyl radicals significantly broadens the application scope of carbonyl compounds as synthons, offering a promising approach for carbon-carbon bond formation in organic synthesis. However, achieving cross-coupling and stereocontrol under mild reaction conditions has remained a significant challenge. Here, we report a synergistic catalytic platform that enables highly diastereo- and enantioselective CDC of beta-keto carbonyls with glycine derivatives. The strategy introduces a photoredox catalyst and a chiral magnesium complex catalyst, leveraging the oxidations of the two coupling partners via independent pathways through the use of peroxybenzoate and a catalytic amount of NaI under visible-light irradiation. The beta-carbonyl-substituted glycine derivatives can be readily obtained with exceptional stereocontrol (up to >19:1 dr, >99% ee) and yield, spanning a series of glycinates with both electron-donating and electron-withdrawing N-aryl substitutions. Mechanistic studies reveal a radical pathway rather than oxidative polar addition, showcasing a paradigm for merging photoredox-generated open-shell intermediates in C(sp(3))-H cross-coupling

The manipulation of quantum states in triple-decker organometallic molecules remains challenging due to their complex many-body interactions. In this study, we combine density functional theory (DFT) and the hierarchical equations of motion (HEOM) to map, for the first time, the evolution of quantum states in a triple-decker dinuclear complex under mechanical manipulation by a magnetic cobalt tip. DFT calculations demonstrate that the tip approach induces substantial structural distortion of the molecular framework, which triggers a reconstruction of the internal magnetic coupling network. This process is accompanied by an evolution of the electronic structure that includes modifications to the local density of states, magnetic moment, spin-state populations, and molecular orbital hybridization characteristics. By solving the spin-polarized Anderson model using the HEOM method, we have revealed the dynamic evolution of strongly correlated Kondo effects. When the system enters the contact regime, the Kondo resonance peak exhibits asymmetric splitting, where the splitting characteristics exhibit a simultaneous dependence on the spin polarization degree of the electrodes and the coupling strength between the impurity and the electrodes. These atomic-scale insights into the external control of molecular quantum states provide a robust framework for the future design of molecular spintronic devices.

The dearomative photocycloaddition reactions of (hetero)arene feedstocks have emerged as an efficient platform for the construction of three-dimensional complexity, which is of increasing interest in medicinal chemistry. Nevertheless, the catalytic asymmetric version of such transformations with quinolines remains a challenging task because of regio-, diastereo-, and enantioselective control. Especially the presence of substituents with divergent electronic effects on the aromatic ring presents a regioselectivity control dilemma. Herein, we report highly regio-, diastereo-, and enantioselective dearomative [2 + 2] photocycloadditions of quinolines with bicyclo[1.1.0]butanes (BCBs) by utilizing a chiral Lewis acid-mediated strain-release approach. The regioselectivity and stereocontrol challenges were addressed by strategically designing catalysts with tailored steric bulk that modulated the chiral pocket in response to the electronic and steric characteristics of diverse substrate substituents. This strategy was compatible with isoquinoline, indole derivatives, naphthalene, and benzo[b]thiophene, providing highly decorated chiral heterocycle-fused bicyclo[2.1.1]hexanes (BCHs) in moderate to good yields with high regio-, diastereo-, and enantioselectivities (52 examples, up to 99% yield, >19:1 rr, >19:1 dr, 99% ee). Based on experimental studies and theoretical calculations, a catalytic cycle along with possible transition states was provided to understand the reaction mechanism.

Magnetic molecules adsorbed on two-dimensional (2D) substrates have attracted broad attention because of their potential applications in quantum device applications. Experimental observations have demonstrated substantial alteration in the spin excitation energy of iron phthalocyanine (FePc) molecules when adsorbed on nitrogen-doped graphene substrates. However, the underlying mechanism responsible for this notable change remains unclear. To shed light on this, we employ an embedding method and ab initio quantum chemistry calculations to investigate the effects of surface doping on molecular properties. Our study unveils an unconventional chemical bonding at the interface between the FePc molecule and the N-doped graphene. This bonding interaction, stronger than non-covalent interactions, significantly modifies the magnetic anisotropy energy of the adsorbed molecule, consistent with experimental observations. These findings provide valuable insights into the electronic and magnetic properties of molecules on 2D substrates, offering a promising pathway for precise manipulation of molecular spin states.

Developing novel strategies for catalytic asymmetric dearomatization (CADA) reactions is highly valuable. Visible light-mediated photocatalysis is demonstrated to be a powerful tool to activate aromatic compounds for further synthetic transformations. Herein, a catalytic asymmetric dearomative [2 + 2] photocycloaddition/ring-expansion sequence of indoles with simple alkenes was reported, providing a facile access to enantioenriched cyclopenta[b]indoles with good to high yields and enantioselectivities by means of chiral lanthanide photocatalysis. This protocol exhibited a broad substrate scope and good functional group tolerance, as well as potential applications in the synthesis of bioactive molecules. Mechanistic studies, including control experiments, UV-vis absorption spectroscopy, emission spectroscopy, and DFT calculations, were carried out, shedding insights into the reaction mechanism and the origin of enantioselectivity.

The structural elucidation of chiral rare-earth-based catalysts in asymmetric reactions holds significant importance as it is crucial for comprehending their operational mechanisms and for broadening their applications in the realm of asymmetric synthesis. Herein, a La-III/(L-3-RaMe3)(2) complex was identified to be more active and enantioselective than La-III/L-3-RaMe3 in the asymmetric formal substitution of racemic 3-bromo-3-substituted oxindoles with TMSCN. The experimental studies and theoretical calculations disclosed that the partial dissociation of the chiral N,N '-dioxide ligand was involved in the catalytic process with La-III/(L-3-RaMe3)(2). These insights provided a rationale for the remarkable effect of catalyst structures on the results and nonlinear effect observed in the current reaction system. This protocol offers a straightforward and efficient pathway to synthesize various chiral 3-cyano-3-substituted oxindoles (53 examples, up to 99% yield, 98% ee). In addition, the synthesis of a bioactive compound CRTH2 receptor antagonist and obvious inhibitory effect of several products on the viability of cancer cells demonstrate the potential utility of this methodology.

Visible-light-driven direct asymmetric α-C(sp3)-H bond functionalization of glycinate provides a direct and efficient route for the synthesis of diverse optically enriched α-amino acid derivatives. However, asymmetric coupling between glycinate radical species and ketones faces significant challenges, including competitive pathways, mutable intermediates, as well as congested stereogenic centers. Herein, we disclose the first example for the asymmetric photocatalytic synthesis of a diverse array of β-diaryl-β-hydroxy-α-amino acetate derivatives from glycinates and heteroaryl ketones through the synergistic catalysis of achiral iridium photoredox catalyst and chiral lanthanide Lewis acid catalysts. The enantioselective radical addition pathway is supported by spectroscopic experiments, control experiments and DFT calculations.

Chiral acyclic α-tertiary amino ketones are widely present in various natural products and pharmaceuticals; however, the direct synthesis of this pharmacophore through a robust strategy still presents significant challenges. The emerging photocatalysis provides a powerful approach to construct chemical bonds that are difficult to form via a traditional two-electron pathway. Herein, we developed visible-light-induced chiral Lewis acid-catalyzed highly enantioselective acylation/alkylation of aldimines enabled by cooperative FLN (9-fluorenone) electron-shuttle catalysis via radical addition. An array of α-tertiary amino ketones, β-amino alcohols, and chiral amines were achieved with high yields and good to excellent stereocontrol (87 examples, up to 84% yield, 96% ee). These products can be easily transformed into valuable and bioactive skeletons. Extensive control experiments, detailed mechanism studies, and density functional theory calculations elucidated the reaction process and highlighted the crucial role played by FLN.

Single-molecule magnets (SMMs) possess a crucial property called magnetic anisotropy (MA), which has an exceedingly delicate correlation with their structures. In recent years, the study on magneto-structural correlations has emerged as a challenging area in singlemolecule science. Understanding the fundamental physical mechanisms underlying the magneto-structural correlations is essential for building excellent high-temperature SMMs. In this work, we screened various four-coordinated nickel(II) SMMs and studied several key structural factors, such as the lengths and angles of the coordination bonds that may be closely associated with MA. Following that, we developed simple molecular models to deduce the evolution trends of MA with coordination bond angles and lengths. The findings on the magneto-structural correlations stimulated our interest to further explore the crystal structure database. We revealed that the magneto-structural correlation can be well described by a logarithmic function. Guided by such a relationship, we discovered a nickel(II) complex with the strongest MA to date among the tetrahedral-coordinated ones. Our work may be helpful for the empirical synthesis of exceptional high-temperature SMMs.

We realized a highly efficient formal [1,2]-sigmatropic rearrangement of ammonium ylides generated from 3-methylene-azetidines and α-diazo pyrazoamides. The employ of readily available chiral cobalt(II) complex of chiral N , N′ -dioxide enabled the ring-expansion of azetidines, affording a variety of quaternary prolineamide derivatives with excellent yield (up to 99 %) and enantioselectivity (up to 99 %  ee ) under mild reaction condition. For the rearrangement of ammonium ylides, the installation of a pyrazoamide group as a masked brick to build chiral scaffolds proved successful. The enantioselective ring expansion process was elucidated by DFT calculations.

A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed, which exhibits good functional group compatibility, high atomic and step economy. This protocol utilizes a strategy of synergistic catalysis with a chiral N,N′-dioxide/NiII complex and an achiral Pd0 catalyst, generating a series of multi-substituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-, Z/E- and enantioselectivity under mild conditions. Further transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product analogues. Experimental studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E- and enantioselectivity. The density functional theory (DFT) calculations further demonstrated that multiple C–H;·;·;·π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.

Fine-tuning the magnetic anisotropy energy (MAE) of a magnetic molecule with a high precision of sub-meV has been realized experimentally by manipulating the tip of a scanning tunneling microscope (STM). Understanding the mechanisms behind the observed evolution of spin excitation energy is essentially important for potential spintronic applications. In particular, it is crucial to unveil the influence of the surrounding environment on the molecular spin state. To this end, we carry out the first-principles simulation on the STM-tip control of an iron octaethylporphyrin chloride (Fe-OEP-Cl) molecule adsorbed on the Pb(111) substrate. By carefully taking into account the atomic structures of the tip and the substrate as well as the multireference feature of the Fe 3d electrons, the experimentally measured evolution of spin excitation energy, including a continuous increase, followed by a sudden drop in the MAE, is accurately reproduced by our simulation with a maximal discrepancy of less than 0.3 meV. Based on a comprehensive analysis of the change in geometric and electronic structures of the whole single-molecule junction, the exotic evolution of MAE is attributed to the variation of the ligand confinement effect and the resulting charge transfer. The unique role of the single-atomic Cl ligand is clarified by comparing the evolution under the STM-tip control with that of the tip/Fe-OEP/Pb(111) junction. The theoretical insights provided by this work would be valuable for the on-demand design of the mechanically controlled magnetic nanojunctions.

Circular dichroism (CD) is broadly employed for distinguishing molecular chiralities. However, its practical application is often limited by the weak magnitude of chiral signal. We propose to use azimuthally and radially polarized vector beams to probe CD spectra. By taking advantage of the strong longitudinal components of the vector beams, the transmitted light can be detected in the radial direction. The resulting CD signal is several orders of magnitude stronger than conventional CD signal with plane waves. Quantitative analysis and numerical simulations show that the enhancement factor is independent of molecular properties and can be increased by decreasing the path length of the sample cuvette and the interaction cross section between the light beam and molecular sample. The proposed novel CD spectroscopy is feasible with the current optical technology.