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In biology, the specific enzyme-mediated cleavage of peptide and protein backbones plays numerous regulatory roles. Being able to mimic the specificity and efficacy of enzymes, using chemical methods, is a grand challenge. Nevertheless, specific chemical cleavage of protein backbones at cysteine residues dates back to the 1960s. In this concept, recent insights and developments in chemical peptide and protein backbone cleavage as well as their applications for the selective manipulation and functionalization of proteins are discussed.

A ternary metal catalyst system based on Pd/C-Pt/C-Ru/C and molecular oxygen is found to be very effective and robust in oxidizing alcohols to carboxylic acids. Using the ternary catalyst and a flow-setup, the conversion of 5-hydroxymethylfurfural (HMF, 1) to 2,5-furandicarboxylic acid (FDCA, 2), a bioplastics precursor, proceeded quite rapidly with a residence time of 1 min at 120 °C under 0.28 MPa of molecular oxygen. Catalyst activity remains stable for at least 2 weeks, giving 66.8 g (60% yield) of the analytically pure FDCA (2). The ternary catalyst system combined with a flow setup is successfully applied to the rapid conversion of ordinary alcohols 3 to aromatic and aliphatic carboxylic acids 4 in good yields.

Molecular design strategies are essential for rationalizing the aqueous self-assembly behavior of π-conjugated amphiphilic molecules and for clarifying the relationship between their photophysical properties and nanostructure morphology. Despite notable advances in understanding structure–property relationships that enable the selective formation of face-to-face (H-type) and slipped (J-type) aggregates in water, accurately predicting self-assembly outcomes and resulting functions remains challenging. This is partly because the molecular requirements governing other exciton coupling modes, such as oblique-type interactions, and their effects on aggregate morphology are still poorly understood. Herein, a molecular design strategy employing amphiphilic aza-BODIPY dyes that enables precise tuning of exciton coupling (J-type vs oblique) and nanoscale morphology in aqueous environments is presented. By systematically varying both the number and positioning of hydrophilic triethylene glycol chains and the length of hydrophobic alkyl substituents, the structure–property relationships that govern self-assembly behavior, employing a combination of theoretical, spectroscopic, and microscopic methods are elucidated. This work advances the understanding of exciton coupling beyond the well-studied H- and J-type aggregates and provides new design principles for engineering functional materials through supramolecular self-assembly.

Subphthalocyanines (SubPcs) currently hold a privileged position among the most versatile scaffolds for the design of π-conjugated materials. In this context, the remarkable chemical tunability of these macrocycles has played a pivotal role, which has given rise to a unique and rich chemistry over the past two decades. Most recently, postfunctionalization strategies have been successfully applied at the axial ligand, the peripheral positions, and remote sites from the SubPc core. However, each of these approaches requires careful selection of reaction conditions, considering the high sensitivity of SubPcs against strong nucleophiles. In this review, a comprehensive overview of the full synthetic toolbox available for the postfunctionalization of SubPcs is provided. Special emphasis is placed on reaction conditions, functional group tolerance, and structural scope, as well as mechanistic insights when available. Finally, the main synthetic challenges that remain to be addressed in order to fully exploit the potential of SubPc chemistry are outlined. Altogether, this review aims to serve not only as a practical guide for chemists working in the field, but also as an inspiration for future developments in the chemistry of curved π-conjugated systems.

The present contribution comprehensively reviews the coordination chemistry of N-heterocyclic carbene (NHC) bis-phenolate tridentate ligand of the type [OCO] to various metal and heteroatom centers. The structural features of the resulting robust [OCO]M chelates are discussed along with their unique and specific properties, including emerging redox and optical properties of such complexes. Thanks to their stability and electronic features, this class of robust metal chelates has already been exploited for various catalytic applications, most notably the controlled polymerization of polar cyclic monomers and olefins, N₂ reduction and photoinduced catalysis. In addition, some [OCO]M complexes have also been shown to stoichiometrically activate/functionalize small molecules such as O₂ and NH₃. All these aspects, some of them just emerging, are discussed herein along with future research opportunities on [OCO]M chelates.

Organic mechanochemistry is currently undergoing rapid advances, significantly contributing to sustainability and green chemistry by eliminating toxic organic solvents. This discipline can further contribute to sustainability and safety by allowing the use of well-chosen, safer, and easier-to-handle reactants, e.g., solid reagents. The solvent-free conditions inherent to mechanochemistry enhance, in many cases, the reactivity of these solid reagents, which would otherwise be ineffective in solution, representing a new paradigm for organic reactions. This Minireview aims to emphasize the synergistic benefits of mechanochemistry and solid reagents in replacing hazardous substances typically used in organic synthesis. It will also highlight examples of well-known reactions that have experienced notable improvements in reactivity or selectivity using safer solid bases, acids, or gas surrogates. This represents an important transformative shift toward greener and safer methodologies in the field of organic chemistry.

Unusually high coordination number for elements has been of great interest in chemistry. Herein, a new class of hexacoordinated carbon compounds with stoichiometry MCF₆ (M = Ca, Sr) at 400 and 500 GPa and K₂CF₆ at 500 GPa is found using crystal structure predictions assisted by first-principles calculations. . At high pressure, MCF₆ (M = Ca, Sr) adopts a trigonal structure (R $$) that is isomorphous with several other species with M^IIA^IVF₆ (A = Si, Ge, and Sn) while K₂CF₆ adopts a trigonal structure (P$$m1) akin to M₂^IA^IVF₆. Both the species are thermodynamically more stable than the bicomponent MF₂/KF…CF₄ mixture at high-pressure region. These solid-state structures are dynamically stable over a wide range of pressure. For all cases, the main building block of the solid-state structures is the [CF₆]²⁻ unit in which carbon attains a perfectly octahedral coordination of the six fluoride anions. The present study establishes new fluorine-rich carbon compounds and predicts a new class of perfectly hexacoordinated carbon species. For the first time, the stabilization of [CF₆]²⁻ in the solid-state is reported.

Carbocationic rearrangements are fundamental to both biosynthetic and synthetic chemistries, yet their high reactivity and mechanistic complexity often defy intuitive prediction of outcomes. Herein, HopCat, a hybrid algorithmic platform combining rule-based transformation logic with quantum-mechanically informed kinetics, is applied to explore the rearrangement networks of acid-catalyzed terpenoid transformations. Using a series of terpenoid substrates, an array of structurally diverse and unprecedented products is obtained. It is narated how HopCat can work synergistically with a human chemist to guide product assignment, downselect product candidates based on NMR cues, and reconstruct plausible, multistep mechanistic pathways, including those involving unanticipated intermediates.

Fundamental studies of diffusion processes on solid catalysts are challenging due to the lack of appropriate characterization techniques. Herein, using NH₃ diffusion on various zeolites as an example, flow-pulse adsorption microcalorimetry (FPAM) is demonstrated capable of characterizing diffusion processes on solid catalysts. Initial adsorption heats and differential adsorption heats of NH₃ on zeolites are measured temperature-dependent arising from the diffusion of adsorbed NH₃ from the weakly adsorbed Lewis acidic sites (LAS) to the strongly adsorbed Brønsted acid sites (BAS). A model is then established to acquire the temperature-dependent distributions of NH₃ adsorbed at the LAS and BAS sites, from which the LAS-to-BAS diffusion barrier of adsorbed NH₃ is derived between 3.1 and 7.4 kJ mol⁻¹ mainly related to the binding energy of NH₃ adsorbed at the LAS. The applicability of FPAM method is further demonstrated by determing the weak adsorption site-to-strong adsorption site diffusion barriers of adsorbed NH₃ on silicalite-1 and adsorbed C₃H₆ on MOR-10 as 7.3 and 17.9 kJ mol⁻¹, respectively. The established FPAM method is a general method and will greatly enable the studies of diffusion processes on solid catalysts, a key elementary step capable of regulating their catalytic performances.

Decoration of polymers with Lewis acidic borane moieties is attractive as it enables the development of functional materials for use as powerful supported catalysts, chemical sensors, and building blocks of novel supramolecular materials. The dynamic nature of Lewis acid-base interactions is of central importance in these application fields. However, methods to access well-defined polymeric Lewis acids with tunable Lewis acid characteristics remain very limited. In this article, a flexible route to a family of norbornene-functionalized triarylboranes is reported, which can be polymerized under mild conditions using ring-opening metathesis polymerization to yield borane Lewis acid-functionalized homo- and copolymers. By varying the aryl substituents about the boron center, steric and electronic tuning of the Lewis acid moieties is achieved. The latter allows for the rational design of polymers with tunable Lewis acid strength, approaching that of the widely utilized molecular Lewis acid B(C₆F₅)₃, enhanced air-stability, and desirable luminescent characteristics. The complexation behavior, stability, and photophysical properties of the new monomers and borane polymers are investigated in depth.