Herein, we reports an efficient and green one-step method for synthesizing thiophene-substituted ketones from 2-thiophenemethanol and ketones via dehydrogenative coupling using manganese complexes as catalysts. Utilizing this strategy, we carried out an efficient and diverse reaction of ketones with 2-thiophenemethanol, and successfully synthesized a series of thiophene-substituted saturated ketones and α, β-unsaturated ketones in good isolated yields.

Abstract

This study reports an efficient and green one-step method for synthesizing thiophene-substituted ketones from 2-thiophenemethanol and ketones via dehydrogenative coupling using manganese complexes as catalysts. The manganese complex demonstrated a broad applicability under mild conditions and extended the range of usable substrates. Utilizing this strategy, we carried out an efficient and diverse reaction of ketones with 2-thiophenemethanol, and successfully synthesized a series of thiophene-substituted saturated ketones and α, β-unsaturated ketones in good isolated yields.

The significance of fluorine atoms: The cover artwork symbolizes the importance of fluorine atoms on drug molecules, just as the red flower blossoms bring beauty and brilliance to an old tree. Although fluorine atoms greatly enhance the biological properties of pharmaceuticals and agrochemicals, fluorination reactions present persistent challenges due to their hazardous nature and limited selectivity and scalability. This review explores recently developed continuous flow techniques that addressed the challenges of fluorination reactions. The design and application of continuous flow systems specifically for fluorination reactions are discussed. More information can be found in the Review by Tsz Chun Lee, Yi Tong, and Wai Chung Fu.

Photoinduced organic synthesis, recognized for its eco-friendliness, represents a green energy alternative. The catalyst-free photoinduced approach has gained prominence in contemporary times, especially in synthesis. This review endeavors to collect relevant literature pertaining to photo-induced borylation reactions without photocatalysts and transition metals.

Abstract

The increasing global warming concerns have propelled a surge in the demand for sustainable energy sources within the domain of synthetic organic chemistry. A particularly prominent area of research has been the development of mild synthetic strategies for generating heterocyclic compounds. Heterocyclic compounds containing boron have notably risen to prominence as pivotal reagents in a myriad of organic transformations, showcasing their wide-ranging applicability. This comprehensive review is aimed at collecting the literature pertaining to borylation reactions induced by light, specifically focusing on photocatalyst-free and transition metal-free methodologies. The central emphasis is on delving into selective mechanistic investigations. The amalgamation and analysis of these research insights elucidate the substantial potential inherent in eco-friendly approaches for synthesizing heterocyclic compounds, thus propelling the landscape of sustainable organic chemistry.

The reaction between [2-(MeOCH₂)C₆H₄]MgBr and SnCl₄ yielded the highly crowded stannanes [2-(MeOCH₂)C₆H₄)]₃SnBr (1), [2-(MeOCH₂)C₆H₄)]₂SnX₂ (2, X₂=Br₂ (a) and BrCl (b)), together with trace amounts of the distannane [{2-(MeOCH₂)C₆H₄}₃Sn]₂ (3), and a distannoxane [2-{(MeOCH₂)C₆H₄)}₂SnBr]₂O (4). The new compounds 1–4 were characterized by single crystal X-ray crystallography showing that 1, 2a and 4 exhibit significant Sn…O secondary bonding interactions that persist in solution for 1.

Abstract

The reaction between the Grignard reagent formed from Mg and 2-bromobenzylmethyl ether and SnCl₄ produced four products: [2-(MeOCH₂)C₆H₄]₃SnBr (1), [2-(MeOCH₂)C₆H₄]₂SnX₂ (2, X₂=Br₂ (a) and BrCl (b)), [{2-(MeOCH₂)C₆H₄}₃Sn]₂ (3), and [{2-(MeOCH₂)C₆H₄}₂SnBr]₂O (4). In the case of 1, two of the three dangling arm O atoms coordinate to the central tin atom with O−Sn internuclear distances of 2.53 (O1) and 2.91 (O2) Å, the shorter interaction being trans to the Br atom, the other trans to a phenyl carbon atom. In the case of 2a the resulting hexacoordinate structure exhibits two very short O−Sn interactions of 2.42 and 2.50 Å, well below the sum of the VdW radii of O and Sn, 3.69 Å. The sterically crowded ditin compound 3 was obtained in trace amounts and the structure demonstrates no dangling O−Sn interactions. General changes in structure compared to other distannane systems are reflective of the great steric crowding. Distannoxane 4, has a Sn−O−Sn bond angle of 148.1(2)° which is larger compared to other distannoxane structures. The intermolecular interactions between Sn−O 2.470(3) and 2.521(3)Å and 2.665(3) and 2.629(3)Å for Sn1 and Sn2 respectively are responsible for a distorted octahedral geometry around the two tin atoms. The various ¹¹⁹Sn_, ¹³C and ¹H NMR spectra are in accord with their structural analysis for 1 and 2, and in the solid state ¹³C NMR spectrum of 1 the dangling methylene group is observable whereas is solution there is a rapid dynamic equilibrium resulting in a single resonance for all methylene groups.

A CISC@S/CNTs graded composite electrode with C−O, C−N, and C−S bonds stabilization and CNTs coating protection was prepared using the organic waste chestnut inner shell. It can effectively suppress the shuttling effect of sulfur and polysulfide ions, enhance the charge and electrolyte transfer kinetics, and provide an effective way to commercialize lithium-sulfur batteries.

Abstract

The shuttle effect of lithium-sulfur (Li−S) batteries and the poor conductivity of sulfur (S) and lithium polysulfide severely limit their practical applications. Currently, compounding carbon materials with S is one of the effective ways to solve this problem. Therefore, green, low-cost chestnut inner shell biochar (CISC) with graded porous structure was used as the S carrier in this experiment, and carbon nanotubes (CNTs) coating was employed as the S protective layer to improve the electrical conductivity and inhibit the shuttle effect. The results showed that the CISC prepared in this experiment had a relatively high specific surface area (1135.11 m² g⁻¹), and the S loading rate was as high as 65.72 %. The graded porous structure and high specific surface area of CISC can increase the loading rate of S and thus increase the battery capacity. Meanwhile, the naturally contained O and N elements can improve the chemisorption of S. The initial discharge capacity of the CISC@S/CNTs battery at 0.1 C is 967.3 mAh g⁻¹, and the capacity retention rate is 74.3 % after 500 cycles. The unique composite structure improves the battery‘s electrical conductivity, reduces the dissolution of polysulfides, and enhances the battery cycle stability.

Chiral carbon dots can be widely used in various fields such as chiral recognition, chiral catalysis and biomedicine because of their unique optical properties, low toxicity and good biocompatibility. In addition, chiral carbon dots with circularly polarized luminescence (CPL) can be synthesized, thus broadening the prospects of chiral carbon dots applications. Since the research on chiral carbon dots is still in its infancy, this paper reviews the chiral origin, formation mechanism, chiral evolution, synthesis and emerging applications of chiral carbon dots, with a special focus on chiral carbon dots with CPL activity. It is hoped that it will provide some reference to solve the current problems faced by chiral carbon dots. Finally, the opportunities and challenges of the current research on chiral carbon dots are described, and their future development trends have also been prospected.

Red fluorescent proteins (RFPs) have powered bioimaging advances due to their long-wavelength emissions and reduced phototoxicity. We present a comprehensive review of major categories of RFPs including the photoconvertible, photoswitchable, and large Stokes shift (LSS) FPs that achieve red emissions. We critically correlate the available crystallographic and spectroscopic results for ultrafast and functional structural dynamics insights into their redding mechanisms.

Abstract

Red fluorescent proteins (RFPs) represent an increasingly popular class of genetically encodable bioprobes and biomarkers that can advance next-generation breakthroughs across the imaging and life sciences. Since the rational design of RFPs with improved functions or enhanced versatility requires a mechanistic understanding of their working mechanisms, while fluorescence is intrinsically an ultrafast event, a suitable toolset involving steady-state and time-resolved spectroscopic techniques has become powerful in delineating key structural features and dynamic steps which govern irreversible photoconverting or reversible photoswitching RFPs, and large Stokes shift (LSS)RFPs. The pertinent cis-trans isomerization and protonation state change of RFP chromophores in their local environments, involving key residues in protein matrices, lead to rich and complicated spectral features across multiple timescales. In particular, ultrafast excited-state proton transfer in various LSSRFPs showcases the resolving power of wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in mapping a photocycle with crucial knowledge about the red-emitting species. Moreover, recent progress in noncanonical RFPs with a site-specifically modified chromophore provides an appealing route for efficient engineering of redder and brighter RFPs, highly desirable for bioimaging. Such an effective feedback loop involving physical chemists, protein engineers, and biomedical microscopists will enable future successes to expand fundamental knowledge and improve human health.

Two Zn(II) based compounds, [Zn2L1(OAc)3(MeOH)] (1) and [Zn2L2(OAc)3]n (2) have been reported where HL1 is (E)-4-Bromo-2-methoxy-6-(((2-morpholino ethyl)imino) methyl)phenol and HL2 is (E)-4-Bromo-2-methoxy-6-(((2-(piperazine-1-yle)ethyl)imino)methyl) phenol. SCXRD  analysis unveils vivid change in structural arrangements and dimensionality from 1 to 2 due to change in coordinated atom from oxygen to nitrogen of the ligands. SCXRD study shows that compound 1 is dinuclear but compound 2 has a 1-dimensional polymeric structure having helical chain. Structural diversity greatly influences the catalytic activity. Compound 1 acts as excellent catalyst for conversion of 3, 5-di-tert-butyl catechol (3, 5-DTBC) to 3, 5-di-tert-butylbenzoquinone (3, 5-DTBQ) with the turnover number (kcat) value of 34.94 sec-1. Further, compound 1 reveals phosphatase like activity for conversion of disodium salt of (4-nitrophenyl)-phosphate hexahydrate to p-nitrophenolate with the kcat value of 24.64 sec-1. Amusingly, compound 2 does not show any catalytic activity. To correlate this distinctly different catalytic behavior of two compounds, DFT calculation was carried out. The calculation reveals that detachment of coordinated methanol from coordination sphere of zinc in compound 1 is energytically favourable which creates room for substrate binding, resulting high catalytic activity. Whereas in compound 2, detachment of piperazine or Zn-O of –COOH group are energetically unfavouable, resulting no catalytic activity.

Recent advancements in the development of metal-organic framework-based membranes using various fabrication strategies for hydrogen gas separation are covered in this review.

Abstract

Metal-organic frameworks (MOFs) are promising porous materials that have huge potential for gas separation when put in the membrane configuration. MOFs have huge potential due to certain salient features of the MOFs such as excellent pore size, ease of tuning the pore chemistry, higher surface area, and chemical and thermal stabilities. MOFs have been explored for various gas separation and storage applications. This review discusses various approaches for fabricating MOFs-based membranes for the separation of H₂ gas from a variety of feeds having various gases CO₂, CO, N₂, and CH₄ as impurities. The emphasis has been put on three types of membranes for H₂ separation which include MOFs-based hollow fibrous/tubular/disk membranes, MOFs-based mixed matrix membranes (MMMs), and MOFs-based stand-alone membranes. In addition, various challenges such as reducing inhomogeneity between MOFs and polymeric matrices have also been discussed. Similarly, the approaches to successfully decorating MOFs on different supports in different configurations have been explained. The possible ways of improving the MOFs-based membranes for H₂ have also been discussed.

A redox-neutral nickel-catalysed sulfonylation for arylsulfone synthesis were developed. (Hetero)aryl boronic acids reacted with potassium metabisulfite (K2S2O5) and readily available 2-chlorothiazoles in the presence of air-stable Ni(OTf)2 and 4,4-di-tert-butyl bipyridine (dtbbpy) as a commercially available ligand to produce the corresponding 2-sulfonylthiazoles in moderate to excellent yields. This practical protocol tolerates a wide range of substrates including boronic acids and 2-chloro(benzo)thiazoles without additional bases, allowing the direct synthesis of functional arylsulfones.