Metal clusters have become increasingly important in various applications, with ligands playing a crucial role in their construction. In this study, we synthesized a bimetallic cluster, Ag6Cu8(C≡CAr)14(DPPB)2 (Ag6Cu8), using a rigid acetylene ligand, 3,5-bis(trifluoromethyl)phenylacetylide. Through single-crystal structure characterization, we discovered that the butterfly-shaped Ag2Cu2 motifs were subject to distortion due to steric hindrance imposed by the rigid ligand. These motifs assembled together through shared vertices and edges. Mass spectrometry analysis revealed that the primary fragments detected during electrospray ionization (ESI) testing corresponded to the Ag2Cu2 motifs. Furthermore, we conducted a comprehensive investigation of the cluster’s solution properties employing 31P NMR, UV-vis absorption, and photoluminescent measurements. In contrast to previously reported Ag/Cu bimetallic clusters protected by flexible ligands, Ag6Cu8 protected by rigid ligands exhibited intriguing room temperature fluorescence properties alongside excellent thermal stability. DFT calculations of the energy levels of Ag6Cu8 and Ag6Cu8 removing aromatic ring revealed that the presence of the aromatic ring can lower the electronic energy levels of the cluster molecule, and reduce the energy gap from 4.05 eV to 3.45 eV. Moreover, the rigid ligand further suppressed the non-radiative transition process, leading to room temperature fluorescence emission.

An efficient palladium-catalyzed denitrogenative transannulation strategy to access various 3-substituted isocoumarin-1-imine frameworks using 1,2,3-benzotriazin-4(3H)-ones and terminal alkynes is described.

Abstract

A palladium-catalyzed denitrogenative transannulation strategy to access various 3-substituted isocoumarin-1-imine frameworks using 1,2,3-benzotriazin-4(3H)-ones and terminal alkynes is described. The reaction is highly regioselective and tolerates a wide range of functional groups. The reaction is believed to proceed via a five-membered palladacycle intermediate extruding environmentally benign molecular nitrogen as a by-product. The utility of this method was showcased through the one-pot synthesis of biologically relevant 3-substituted isocoumarin scaffolds.

A detailed DFT mechanistic investigation on redox neutral nickel(II)-catalyzed arylative cyclization reactions of a tethered allene-ketone with arylboronic acids. This work highlights that the transformation consists of three key elementary steps: (i) base-free transmetalation, (ii) cationic terminal allene insertion, and (iii) a diastereo- and enantio-determining cyclization step.

Abstract

Density functional theory (DFT) has provided a detailed mechanistic picture for the redox neutral nickel(II)-catalyzed arylative cyclization reactions of a tethered allene-ketone with arylboronic acids. A mechanistic rationale for the high diastereo- and enantioselectivity achieved experimentally at high reaction temperature was uncovered through modeling the reaction with a chiral ligand and the predicted stereochemical outcome corroborates with experimental results. An unprecedented mechanism for the base-free organoboron transmetalation was revealed and the regioselectivity of migratory insertion of tethered allene-ketones as well as the stability of the possible allylnickel isomers (σ-allyl vs π-allyl) were clarified. The multifaceted nature of the reaction is revealed with certain elementary steps preferring cationic compared to the neutral state.

This paper presents recent advances in photo, electro, and magneto responsive smart superhydrophobic materials, focusing on the synthesis, modification, properties, and responsive behaviours of photo, electro, and magneto responsive smart superhydrophobic materials in response to different external stimuli, and also explores the challenges associated with different types of responsive superhydrophobic materials, as well as the unique prospects for the application of photo, electro, and magneto responsive superhydrophobic materials.

Abstract

With the rapid advancement of technology, the wettability of conventional superhydrophobic materials no longer suffice to meet the demands of practical applications. Intelligent responsive superhydrophobic materials have emerged as a highly sought-after material in various fields. The exceptional superhydrophobicity, reversible wetting, and intelligently controllable characteristics of these materials have led to extensive applications across industries, including industry, agriculture, defense, and medicine. Therefore, the development of intelligent superhydrophobic materials with superior performance, economic practicality, enhanced sensitivity, and controllability assumes utmost importance in advancing technology worldwide. This article provides a summary of the wettability principles of superhydrophobic surfaces and the mechanisms behind intelligent responsive superhydrophobicity. Furthermore, it reviews and analyzes the recent research progress on light, electric, and magnetic responsive superhydrophobic materials, encompassing aspects such as material synthesis, modification, performance, and responses under diverse external stimuli. The article also explores the challenges associated with different types of responsive superhydrophobic materials and the unique application prospects of light, electric, and magnetic responsive superhydrophobic materials. Additionally, it outlines the future directions for the development of intelligent responsive superhydrophobic materials.

A jellyfish-like tetraazide Hf₂(μ-1,1-N₃)₂(N₃)₂ supported by a new pyrazolate-bridged ligand was designed and synthesized from a dihafnium chloride precursor reacting with NaN₃, which further generated a tetranuclear hafnium imido complex from a putative dinuclear Hf^IV-nitridyl intermediate under reduction conditions.

Abstract

Di- and multinuclear hafnium complexes bridged by ligands have been rarely reported. In this article, a novel 3,5-disubstituted pyrazolate-bridged ligand LH₅ with two [N₂N]²⁻-type chelating side arms was designed and synthesized, which supported a series of dinuclear hafnium complexes. Dinuclear hafnium azides [LHf₂(μ-1,1-N₃)₂(N₃)₂][Na(THF)₄] 3 and [LHf₂(μ-1,1-N₃)₂(N₃)₂][Na(2,2,2-Kryptofix)] 4 were further synthesized and structurally characterized, featuring two sets of terminal and bridging azido ligands like jellyfishes. The reactivity of 3 under reduction conditions was conducted, leading to a formation of a tetranuclear hafnium imido complex [L¹Hf₂(μ¹-NH)(N₃){μ²-K}]₂ 5. DFT calculations revealed that the mixed imido azide 5 was generated via an intramolecular C−H insertion from a putative dinuclear Hf^IV-nitridyl intermediate.

1,2-Diamines are synthetically important motifs in organo-catalysis, natural products, and drug research. Continuous utilization of transition-metal based catalyst in direct 1,2-diamination of olefines, in contrast to metal-free transformations, with numerous impressive advances made in recent years (2015-2023). This review summarized contemporary research on the transition-metal catalyzed/mediated [e.g., Cu(II), Pd(II), Fe(II), Rh(III), Ir(III), and Co(II)] 1,2-diamination (asymmetric and non-asymmetric) especially emphasizing the recent synthetic methodologies and mechanistic understandings. Moreover, up-to-date discussion on (i) paramount role of oxidant and catalyst (ii) key achievements (iii) generality and uniqueness, (iv) synthetic limitations or future challenges, and (v) future opportunities are summarized related to this potential area.

The primary method for hydrogen production is through methane steam reforming (MSR) of natural gas. This process involves the reaction between methane and steam to create a synthesis gas (syn gas). Following this, a step referred to as water-gas shift (WGS) is employed. During the WGS process, the hydrogen content is enhanced as H₂O reacts with CO at lower temperatures. Subsequently, hydrogen is extracted from the gas using pressure swing adsorption (PSA). The remaining off-gas is combusted with additional natural gas to generate the heat necessary for MSR. It is imperative to emphasize the significance of synthesizing steam reforming catalysts with high activity and durability to enable large-scale hydrogen production. Recent advancements in bimetallic catalysts for steam reforming have led to enhanced performance in steam methane reforming. This improvement is attributed to the synergistic interaction between two metals in the catalyst.

Abstract

As energy demand continues to rise and the global population steadily grows, there is a growing interest in exploring alternative, clean, and renewable energy sources. The search for alternatives, such as green hydrogen, as both a fuel and an industrial feedstock, is intensifying. Methane steam reforming (MSR) has long been considered a primary method for hydrogen production, despite its numerous advantages, the activity and stability of the conventional Ni catalysts are major concerns due to carbon formation and metal sintering at high temperatures, posing significant drawbacks to the process. In recent years, significant attention has been given to bimetallic catalysts as a potential solution to overcome the challenges associated with methane steam reforming. Thus, this review focuses on the recent advancements in bimetallic catalysts for hydrogen production through methane steam reforming. The review explores various aspects including reactor type, catalyst selection, and the impact of different operating parameters such as reaction temperature, pressure, feed composition, reactor configuration, and feed and sweep gas flow rates. The analysis and discussion revolve around key performance indicators such as methane conversion, hydrogen recovery, and hydrogen yield.

Carbazolyl-stabilised phosphaketenyltetrylenes were prepared and photolytically decarbonylated. The germylene and stannylene derivatives afforded diphosphene-type dimers, while the plumbylene displayed an unexpected isomerisation reaction and incomplete decarbonylation.

Abstract

Phosphaketenes of divalent group 14 compounds can potentially serve as precursors for the synthesis of heavy multiple-bond systems. We have employed the ^dtbpCbz substituent (^dtbpCbz=1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazolyl) to prepare such phosphaketenyltetrylenes [(^dtbpCbz)EPCO] (E=Ge, Sn, Pb). While the phosphaketenyltetrylenes are stable at ambient conditions, they can be readily decarbonylated photolytically. For the germylene and stannylene derivatives, dimeric diphosphene-type products [(^dtbpCbz)EP]₂ (E=Ge, Sn) were obtained. In contrast, photolysis of the phosphaketenylplumbylene, via isomerisation of the [(^dtbpCbz)PbP] intermediate to [(^dtbpCbz)PPb], afforded an unsymmetric and incompletely decarbonylated product [(^dtbpCbz)₂Pb₂P₂CO] formally comprising a [(^dtbpCbz)PPb] and a [(^dtbpCbz)PbPCO] moiety.

The versatile coordinating nature of N,S bidentate ligands is of great importance in medicinal chemistry imparting stability and enhancing biological properties of the metal complexes. Phenylthiocarbamide-based N,S donor Schiff bases converted into RuII/OsII(cymene) complexes and characterized by spectroscopic techniques and elemental analysis. The hydrolytic stability of metal complexes to undergo metal-halido ligand exchange reaction was confirmed both by the DFT and NMR experimentation. The ONIOM (QM/MM) study confirmed the histone protein targeting nature of aqua/hydroxido complex 2aH with an excellent binding energy of -103.19 kcal/mol. The antiproliferative activity against a panel of cancer cells A549, MCF-7, PC-3, and HepG2 revealed that ruthenium complexes 1a–3a were more cytotoxic than osmium complexes and their respective ligands 1–3 as well. Among these ruthenium cymene complex bearing sulfonamide moiety 2a proved a strong cytotoxic agent and showed excellent correlation of cellular accumulation, lipophilicity, and drug-likeness to the anticancer activity. Moreover, the favorable physiochemical properties such as bioavailability and gastrointestinal absorption of ligand 2 also supported the development of Ru complex 2a as an orally active anticancer metallodrug.

This work presents the design, synthesis, and MAO-B inhibitor activity of a series of chalcogenyl-2,3-dihydrobenzofurans derivatives. Using solvent- and metal-free methodology, a series of chalcogen-containing dihydrobenzofurans 7–9 was obtained with yields ranging from 40% to 99%, using an I2/DMSO catalytic system. All compounds were fully structurally characterized using 1H and 13C NMR analysis, and the unprecedented compounds were additionally analyzed using high-resolution mass spectrometry (HRMS). In addition, the mechanistic proposal that iodide is the most likely species to act in the transfer of protons along the reaction path was studied through theoretical calculations. Finally, the compounds 7b–e, 8a–e, and 9a showed great promise as inhibitors against MAO-B activity.