A Genetically Encoded Picolyl Azide for Improved Live Cell Copper Click Labeling

Bioorthogonal chemistry allows rapid and highly selective reactivity in biological environments. The copper-catalyzed azide–alkyne cycloaddition (CuAAC) is a classic bioorthogonal reaction routinely used to modify azides or alkynes that have been introduced into biomolecules. Amber suppression is an efficient method for incorporating such chemical handles into proteins on the ribosome, in which noncanonical amino acids (ncAAs) are site specifically introduced into the polypeptide in response to an amber (UAG) stop codon. A variety of ncAA structures containing azides or alkynes have been proven useful for performing CuAAC chemistry on proteins. To improve CuAAC efficiency, biologically incorporated alkyne groups can be reacted with azide substrates that contain copper-chelating groups. However, the direct incorporation of copper-chelating azides into proteins has not been explored. To remedy this, we prepared the ncAA paz-lysine (PazK), which contains a picolyl azide motif. We show that PazK is efficiently incorporated into proteins by amber suppression in mammalian cells. Furthermore, PazK-labeled proteins show improved reactivity with alkyne reagents in CuAAC.

An updated review on boron removal from water through adsorption processes

Boron is an essential micronutrient that has raised much interest, given the narrow balance between its necessity and toxicity. Both natural and anthropogenic emissions of boron into water sources can eventually deteriorate water quality and endanger the ecosystem. In this review, we first present a general outline of the importance of boron, boron chemistry in water, boron contamination, and its consequences followed by the recent progress in boron removal methods based on adsorption. The adsorbents for deboronation can generally be classified based on the functional groups present; chelating groups, metal oxides, and layered double hydroxides. To comprehensively address these adsorption methods, a detailed discussion on the reaction mechanism of each system is done followed by a summary of the progress in the field during the past 5 years. Finally, some characterization techniques used in deboronation studies and suggestions for future research and applications together with possible improvements to the existing systems are presented. Graphical abstract

Grafting chelating groups on 2D carbon for selective heavy metal adsorption

Iminodiacetic acid (IDA) is a tridentate ligand, which can capture metal ions by forming two fused five-membered chelate rings. In this study, we fixed IDA moieties onto a two-dimensional nanocarbon,...

Influence of α-Coordinating Groups of Aldehyde on E/Z-Selectivity and Use of Quaternary Ammonium Counter Ion For Enhanced E-Selectivity in Julia-Kocienski Reaction.

A modified reaction condition for improved E-selectivity of olefin in Julia-Kocienski reaction of aldehydes having α-coordinating substituents is demonstrated. The chelating groups in aldehyde expected to stabilize syn-transition state (S7)...

Chelation and Stereodirecting Group Effects on Regio- and Diastereoselective Samarium(II)-Water Allylic Benzoate Reductions

SmI2(H2O)n reductions of allylic benzoates adjacent to a trisubstituted alkene occur in high yields with complete regioselectivity and good diastereoselectivity (up to 90:10) for substrates containing properly positioned stereodirecting- and chelating groups. The outcome of these reactions can be rationalized by ring conformation considerations of a proposed chelated organosamarium intermediate, and a mechanism involving intramolecular protonation by a samarium-bound water.

Comparative Study of Synthesis Methods to Prepare New Functionalized Adsorbent Materials Based on MNPs–GO Coupling

In this work, the synthesis of new adsorbent nanomaterials based on the coupling of magnetic nanoparticles and graphene oxide (MNPs–GO) was addressed. Separately, MNPs and GO have adsorbent properties of great interest, but their use involves certain difficulties. The coupling seeks compensation for their disadvantages, while maintaining their excellent properties. Three different routes to synthesize coupled MNPs–GO were studied and are compared in this work. The three synthesized materials were functionalized with chelating groups: [1,5-bis (di-2-pyridyl) methylene] thiocarbonohydrazide (DPTH) and [1,5-bis(2-pyridyl)3-sulfophenylmethylene] thiocarbonohydrazide (PSTH). The new adsorbent nanomaterials were characterized adequately. Moreover, their capacities of adsorption toward heavy and noble metals were determined, in order to apply them as extractants in magnetic solid-phase extraction to preconcentrate metals in environmental samples. The results showed that one of the routes provided nanomaterials with better adsorbent characteristics and higher yields of functionalization.