Reductive site-selective atypical C,Z-type/N2-C2 cleavage allows C-terminal protein amidation

Pd NPs decorated on crosslinked sodium alginate modified iron-based metal-organic framework Fe(BTC) as a green multifunctional catalyst for the oxidative amidation

The primary objective of this investigation was to develop a new nanocatalyst that could produce amides by oxidative amidation of benzyl alcohol, thereby reducing its environmental harm. To achieve this, Pd nanoparticle-immobilized crosslinked sodium alginate-modified iron-based metal-organic framework Fe(BTC) (Fe(BTC)@SA/ED/Pd), with excellent activity and selectivity in modified oxidative amidation of benzyl alcohol with amines, has been described. Crosslinked sodium alginate was modified on iron-based metal-organic framework Fe(BTC). It is worth noting that Pd nanoparticles were immobilized for the first time on a novel nanocomposite based on the Fe(BTC) MOF and crosslinked sodium alginate for tandem oxidative amidation to improve the eco-friendliness and economic efficiency of the process. The synergic effects of Fe(BTC), sodium alginate, and Pd NPs are important factors influencing the catalytic activity. Easy and green synthesis methods, availability of materials, high Pd loading, available catalytic sites, high surface area, high selectivity, and simple separation from the reaction medium are effective properties in catalytic activity.

Harnessing the duality of bases toward controlled color and fluorescence

Bases can promote keto-enol tautomerism, a prevalent form of prototropic tautomerism, and facilitate the ring opening of anhydride ring structures. The intrinsic chemical distinctions between these processes provide an opportunity to modulate these seemingly parallel reactions. However, this potential remains largely unexplored. In this work, we report homophthalic anhydride, the first molecule exhibiting simultaneous halochromism, turn-on fluorescence (halofluorochromism), and subsequent self-destruction. Through comprehensive spectroscopic analysis and theoretical calculations, we unravel the mechanisms underlying these phenomena, revealing that the pivotal roles of the base's basicity and nucleophilicity specifically allow us to achieve controlled durations of color change and turn-on fluorescence. Capitalizing on these intriguing properties, we develop a highly dynamic CMY (cyan-magenta-yellow) palette ideal for entity encryption and anti-counterfeiting applications. Our work reshapes the understanding of the relationship between the basicity and nucleophilicity of bases, enriching the comprehension of keto-enol tautomerism and homophthalic anhydride chemistry, and unveils a spectrum of potential applications.

Carbon-Centered Radicals in Protein Manipulation

Methods to directly post-translationally modify proteins are perhaps the most straightforward and operationally simple ways to create and study protein post-translational modifications (PTMs). However, precisely altering or constructing the C-C scaffolds pervasive throughout biology is difficult with common two-electron chemical approaches. Recently, there has been a surge of new methods that have utilized single electron/radical chemistry applied to site-specifically "edit" proteins that have started to create this potential-one that in principle could be near free-ranging. This review provides an overview of current methods that install such "edits", including those that generate function and/or PTMs, through radical C-C bond formation (as well as C-X bond formation via C• where illustrative). These exploit selectivity for either native residues, or preinstalled noncanonical protein side-chains with superior radical generating or accepting abilities. Particular focus will be on the radical generation approach (on-protein or off-protein, use of light and photocatalysts), judging the compatibility of conditions with proteins and cells, and novel chemical biology applications afforded by these methods. While there are still many technical hurdles, radical C-C bond formation on proteins is a promising and rapidly growing area in chemical biology with long-term potential for biological editing.