Robby Vroemans

A new set of symmetric BOPHY dyes has been successfully applied in photoinduced processes acting as triplet photosensitizers. They have been used not only in bimolecular systems for photon upconversion based on triplet-triplet annihilation but also in generating singlet oxygen for oxidation processes.

Abstract

Encouraged by the successful application of BOPHY dyes in a wide range of scientific fields, from energy to biology, the design of novel compounds based on this type of scaffold appears to be warranted. Herein, we have synthesized a family of symmetric BOPHY dyes bearing arylsulfenyl groups at the 2- and 7-position of the main core, which were fully characterized. The molecular structures were confirmed by the X-ray diffraction (XRD) technique. The photophysical properties were investigated in detail, including spectroscopic measurements and laser flash photolysis experiments. Both the singlet and the triplet excited states of the novel BOPHY dyes were characterized in different solvents. Considering their intersystem crossing quantum yields, these dyes were found to be suitable triplet photosensitizers in bimolecular systems for photon upconversion based on triplet-triplet annihilation. Furthermore, not only direct but also indirect experiments revealed that they effectively acted as photosensitizers for singlet oxygen generation, making them potential candidates for biological applications.

Publication date: 1 November 2025

Source: Coordination Chemistry Reviews, Volume 542

Author(s): Shengran Chang, Songlin Xue, Yanan Yang, Jianming Pan, Weihong Xing

This work pioneers a solvent-free mechanochemical borrowing hydrogen (BH) strategy for the rapid and efficient N-alkylation of amines and heterocycles. By removing harsh conditions and toxic reagents while employing a simple Ru catalyst, this approach redefines BH as a cleaner, more versatile, and sustainable platform for synthetic chemistry.

Abstract

This study presents the first mechanochemical borrowing hydrogenation (BH) strategy, offering a direct and efficient route to N-alkylated amines and heterocycles. This solvent-free approach overcomes many challenges associated with conventional solution-based syntheses, such as toxic reagents, inert atmospheres, high temperatures, lengthy reaction times, excessive catalyst loadings, and the use of solvents. By applying this method under mechanochemical conditions and employing a readily available ruthenium-based catalyst, we achieved high conversions of a diverse set of primary amines and alcohols into N-alkylated amines. Furthermore, kinetic isotope effect (KIE) studies and Hammett analyses provided key insights into the underlying reaction mechanism. Ultimately, this protocol expands synthetic possibilities by facilitating the preparation of heterocycles.

The cross-electrophilic desulfonylative thioetherification of heteroaryl sulfones with thiosulfonates proceeded efficiently via old C–SO₂ bond cleavage and new C–S bond construction with the aid of the cheapest and broadly accessible iron powder as promoter under transition metal catalyst-free conditions, providing a wide spectrum of heteroaryl sulfides in moderate-to-good yields with broad functionality tolerance.

Comprehensive Summary

A desulfonylative thiolation between heteroaryl sulfones and thiosulfonates for the efficient synthesis of heteroaryl sulfides was developed. The cross-electrophile couplings proceeded effectively via old C–SO₂ bond cleavage and new C–S bond formation in the presence of cheapest and widely available iron powder as mediator under transition metal catalyst-free conditions, leading to a wide array of heteroaryl sulfides derived from benzo[d]thiazole, benzo[d]oxazole, thiazole, 1,3,4-thiadiazole, and 1H-tetrazole in modest to excellent yields. In addition, the reaction exhibited good functional group compatibility, and the protocol could also be applicable to the use of selenosulfonate as substrate and be subjected to scale-up synthesis with equal ease. Notably, unreacted iron powder could be readily recovered after reaction by resorting to the attracting property of magnetic stir bar to iron.

 

Abstract

Key to CO₂ reduction transformation is the development of catalysts that efficiently activate inert CO₂ molecules, enabling rapid reaction kinetics with minimal energy inputs. In this study, we introduce N-confused porphyrin (NCP) as a highly active ligand scaffold for transition metal-based catalysts in CO₂ reduction reactions. By breaking the D_4h symmetry inherent in conventional porphyrin structures, NCP promotes enhanced electron delocalization around corresponding metal complex, improving the catalytic efficiency. A comprehensive study demonstrates that NCP-based metal complexes (Fe, Co, and Ni) significantly outperform their parent metal-porphyrin counterparts. These results provide new insights into the design of more effective catalysts for CO₂ reduction.

Nature, Published online: 14 May 2025; doi:10.1038/d41586-025-01072-5

Chia-Hsuan Hsu waited 18 months before chasing an editor for a decision on a paper. The answer surprised him.

An efficient dual photoredox/copper-catalyzed diphosphorothiolation of alkenes with P(O)SH compounds under oxidative conditions was developed, and a diversity of novel vicinal bisphosphorothioates were conveniently synthesized in good yields under mild conditions.

Comprehensive Summary

An efficient photoredox/copper dual-catalyzed 1,2-diphosphorothiolation of alkenes with P(O)SH compounds was realized under oxidative conditions. In this transformation, P(O)SH acted as both the phosphorothioate radical source and the coupling partner. A wide range of valuable vicinal bisphosphorothioates can be easily constructed starting from simple raw materials in a step- and atom-economical manner. Notably, this reaction system has been successfully used to incorporate two phosphorothioate groups into many drug molecules, highlighting the substantial synthetic potential of this protocol.

This minireview discusses MOFs as emerging heterogeneous catalysts for plastic depolymerization. Leveraging their bottom-up designability, thermal stability, and high porosity, MOF catalysts are suitable for a range of different depolymerization reactions for the wide range of plastics currently available.

Abstract

Depolymerization is a promising solution to address the escalating global plastic waste crisis, as a key enabler for emerging technologies in chemical upcycling and closed-loop recycling of plastics. By virtue of their unparalleled bottom-up designability for structural control, stability, reactivity, and compatibility with catalytically-active metal nanoparticles and enzymes, MOFs have enormous potential as an emerging class of porous heterogeneous catalysts for plastics depolymerization. Herein, we highlight key considerations and advances in MOF catalyst development and design for a range of depolymerization reactions, including alcoholysis, hydrogenolysis, pyrolysis, photocatalytic oxidation, and enzymatic hydrolysis. Other than enabling MOFs to efficiently depolymerize the most abundant plastics in production today, including those with unreacted C─C backbones (e.g., polyolefins) and polymers with cleavable backbone linkages (e.g., polyesters), their versatility also extends to emerging applications in microplastic capture and degradation from wastewater. These unique properties of MOFs position them as potentially scalable and reusable heterogeneous catalysts that can complement existing inorganic catalysts for practical depolymerization.

Nature Catalysis, Published online: 25 April 2025; doi:10.1038/s41929-025-01327-4

The catalytic enantioselective formation of alkyl−alkyl bonds from simple feedstock chemicals remains a formidable challenge in organic synthesis. Now, an enantioconvergent approach that couples styrenyl aziridines with unactivated olefins using a chiral nickel catalyst and visible light has been developed.

In the era of landscape of synthetic chemistry, fluorine is widely recognised for its contribution to organic synthesis by augmenting the stability, reactivity, and selectivity of the compounds. This is particularly valuable in drug design, as it boosts the bioavailability of pharmaceutical compounds, thereby optimising their membrane permeability and binding efficiency. Recognising the significant properties and versatile application of fluorine, this review primarily highlights the synthesis of fluorinated compounds via deoxygenated and decarboxylative fluorination.

Abstract

Organic fluorine compounds encompass a vast and diverse variety of species that possess unique biological activity due to the presence of fluorine atoms. Fluorine is highly electronegative, increases the lipophilicity (fat-solubility) and hydrophobicity (water-repellent nature) of molecules, often exhibit remarkable chemical and thermal stability. This is especially useful in drug design, as it can improve the bioavailability of pharmaceutical compounds and help them interact more effectively with biological membranes. The growing demand for fluorinated compounds in materials science, agrochemicals, and medicine has made selective fluorine incorporation into organic molecules a challenging but necessary component of modern organic synthesis. Development of C−F building blocks are invaluable in organic synthesis due to their ability to impart chemical stability, selectivity, and reactivity to organic molecules. This article provides a detailed analysis of two popular fluorination processes: deoxyfluorination and decarboxyfluorination. Deoxyfluorination is the process of enhancing the physicochemical properties of molecules by replacing hydroxyl groups with fluorine atoms. Decarboxyfluorination is a type of chemical reaction where transformation of carboxylic acid derivatives into fluorinated compounds. The various fluorinating reagents, mechanistic processes, synthetic uses and substrate scope are covered in this section. When combined, these novel transformation strategies provide effective and focused approaches to the production of C−F bonds, offering useful resources for obtaining fluorinated compounds. This review mainly focuses on the construction of fluorinated compounds via deoxygenative and decarboxylative fluorination since 2011. We hope this review offers a useful conceptual overview and inspires further advancements in the efficient construction of C−F bond.

Roald Hoffmann's laboratory notebooks and letters provide an inside glimpse into his relationship with R. B. Woodward and the history of the Woodward-Hoffmann rules.

Abstract

In 1965, R. B. Woodward and Roald Hoffmann published five communications in the Journal of the American Chemical Society in which they outlined the mechanisms of electrocyclizations, cycloadditions, and sigmatropic reactions – today known as the Woodward-Hoffmann rules. Over the next several years, the organic chemistry community rushed to test the validity of the W−H rules and expand the range of reactions covered by them. Meanwhile, Woodward and Hoffmann were besieged with invitations to lecture and write expositions on these concepts. In this publication, I present an analysis of Woodward and Hoffmann's next publications in 1966 and 1967 on the W−H rules. Two of these publications were based on lectures Woodward or Hoffmann presented in late 1965 and 1966. I also discuss their own continuing research on the topic in this time period (all by Hoffmann; none by Woodward). I conclude that the assumed intimate collaboration of Woodward and Hoffmann had actually not yet begun.

Alternating polarity (AP) is a powerful tool for controlling selectivity in olefin hydrofunctionalization, but this use is underdeveloped. Using electrochemical olefin hydrocarboxylation as a model, we highlight how AP controls product selectivity, yield, and material decomposition. It hinders overreduction, limiting dicarboxylation and electrode passivation, and facilitates a unique electrochemical–chemical–chemical (ECC) mechanism.

Abstract

The electrochemical generation of radical anions from feedstock olefins offers a selective and efficient route for synthesizing commodity chemicals and pharmaceutical precursors via hydrofunctionalization. Traditional methods for electrochemical olefin hydrofunctionalization, for example, hydrocarboxylation, rely on anion intermediates and follow an electrochemical–chemical–electrochemical–chemical (ECEC) mechanism involving olefin reduction, carboxylation, further reduction, and protonation. Enhancing terminal carboxylate selectivity often requires a proton source, reducing functional group tolerance and favoring proton reduction over olefin reduction. Alternating polarity, a nascent technique in organic electrochemistry, can improve product selectivity by influencing electron transfer rates and electrode surface species. Herein, we report the use of alternating polarity to selectively generate radical anions from styrene derivatives, using electrochemical hydrocarboxylation as a model. This approach shifts the mechanism to an electrochemical–chemical–chemical (ECC) pathway, where the final step involves hydrogen atom transfer. We showcase how alternating polarity modulates product selectivity, yield, and material decomposition, offering new insights into how alternating polarity can advance olefin functionalization by enabling more controlled and selective reaction pathways.

Nature, Published online: 08 April 2025; doi:10.1038/d41586-025-01042-x

Europe must grasp chance to become a scientific powerhouse

A scalable electrochemical strategy for reduction of various aryl alkenes/alkynes to saturated carbon was achieved. The protocol was also applied to dehalogenation of structural versatile aryl/alkyl halides. This strategy shows good functional group compatibility to gain the desired products in good yields under mild reaction condition and air atmosphere with simple undivided electrolysis cell.

Abstract

A facile and efficient electrochemical strategy for reduction of various aryl alkenes/alkynes to aryl alkyl derivatives was achieved. The protocol was also suitable to dehalogenation of structural versatile aryl/alkyl halides. This strategy has good functional group compatibility to gain the desired products in good yields under mild reaction condition and air atmosphere with simple undivided electrolysis cell. The preliminary study of the reaction mechanism was carried out. Gram-scale experiment exhibited the potential application of this method in practical synthesis.

The aminosilane functionalization method allowed the formation of well-dispersed Au nanoparticles with small and uniform sizes supported on TiO₂ nanosheets (AuNPS/TNSs). This catalyst promotes the cross-coupling photoreactions of alcohols derived from biomass and aniline for the synthesis of imines, representing highly atom-efficient processes.

Abstract

Cross-coupling reactions of alcohols and anilines for the synthesis of imines and secondary amines are highly atom-efficient processes. In this study, a visible light photocatalytic procedure was developed for the synthesis of imines on Au nanoparticles supported on TiO₂ nanosheets. AuNPs/TNSs drive the photocatalytic dehydrogenation of the alcohol into an aldehyde, accompanied by the formation of molecular hydrogen, resulting in the condensation of the aldehyde with aniline to obtain the respective imine. Biomass-derived alcohols such as vanillyl, veratryl alcohol, and myrtenol were successfully evaluated in the dehydrogenative condensation with aniline to obtain the respective imines in high yields. Electrochemical analysis confirmed that the high yield of imine (95%) is due to the strong interaction of Au nanoparticles with the TiO₂ nanosheet support, which generates a better separation of the photogenerated electron-hole pairs and a faster interfacial charge transfer, which improves the photocatalytic properties related to the calculated values of photonic efficiency (ξ).