Chemosensors are promising candidates to visualize molecular recognition information through colorimetric or fluorescence responses. In chemosensor designs, the following requirements should be considered; 1) molecular geometries with analytes, 2) mechanisms to cause optical changes upon analyte capture, and 3) solubility for sensing applications. On the other hand, the designs and realization of chemosensors covering the abovementioned requirements are still at the frontiers. In the conventional strategy, molecular geometries between receptors and analytes have been mainly considered. However, this approach confronts issues of synthetic efforts to obtain elaborate designs of chemosensors, which leads to a decrease in the water solubility of chemosensors derived from the complicated and aromatic molecular structures. Herein, this Review summarizes methodologies for self-assembled chemosensors only using off-the-shelf reagents to easily obtain various chemosensors without organic synthesis. The concept of self-assembled chemosensors comprising off-the-shelf reagents with water-solubility realizes not only the easy tuning of optical sensing properties but also chemical sensing in real samples. Through the comprehensive sensing applications using the facile self-assembled chemosensors and their arrays, the usability of off-the-shelf reagents in analytical chemistry will be clarified.
Monthly Archives: October 2023
Review: Direct Lithium Extraction Using Intercalation Materials
Worldwide lithium (Li) demand has surged in recent years due to increased production of Li-ion batteries for electric vehicles and stationary storage. Li supply and production will need to increase such that the transition towards increased electrification in the energy sector does not become cost prohibitive. Many countries have taken policy steps such as listing Li as a critical mineral. Current commercial Li mining is mostly from dedicated mine sources, including ores, clays, and brines. The conventional ways to extract Li+ from those resources are through chemical processing. The environmental and economic sustainability of conventional Li processing has recently received increased scrutiny. Routes such as direct Li+ extraction may provide advantages relative to conventional Li+ extraction technologies, and one possible route to direct Li+ extraction includes leveraging of intercalation materials. Intercalation material processing has recently demonstrated high selectivity towards Li+ as opposed to other cations. Reviews and reports of direct Li+extraction with intercalation materials are limited, even as this technology has started to show promise in smaller scale demonstrations. This paper will review selective Li+ extraction via intercalation materials, including both electrochemical and chemical methods to drive Li+ in and out and efforts to characterize the Li+ insertion/deinsertion processes.
Benzylic C(sp3)‐H bond oxidation with ketone selectivity by a cobalt(IV)‐oxo embedded in a β‐barrel protein
Artificial metalloenzymes have emerged as biohybrid catalysts that allow to combine the reactivity of a metal catalyst with the flexibility of protein scaffolds. Here, we report the artificial metalloenzymes based on the β-barrel protein nitrobindin NB4, in which a cofactor [CoIIX(Me3TACD-Mal)]+X- (X = Cl, Br; Me3TACD = N,N´,N´´-trimethyl-1,4,7,10-tetraazacyclododecane, Mal = CH2CH2CH2NC4H2O2) was covalently anchored via a Michael addition reaction. These biohybrid catalysts showed higher efficiency than the free cobalt complexes for the oxidation of benzylic C(sp3)-H bonds in aqueous media. Using commercially available oxone (2KHSO5·KHSO4·K2SO4) as oxidant, a total turnover number of up to 220 and 97% ketone selectivity were achieved for tetralin. As catalytically active intermediate, a mononuclear terminal cobalt(IV)-oxo species [Co(IV)=O]2+ was generated by reacting the cobalt(II) cofactor with oxone in aqueous solution and characterized by ESI-TOF MS.
Acyclic Boryl Complexes of Copper(I)
Reaction of (6-Dipp)CuOtBu (6-Dipp = C{NDippCH2}2CH2, Dipp = 2,6-iPr2C6H3) with B2(OMe)4 provided access to (6-Dipp)CuB(OMe)2 via σ-bond metathesis. (6-Dipp)CuB(OMe)2 was characterised by NMR spectroscopy and X-ray crystallography and shown to be a monomeric acyclic boryl of copper. (6-Dipp)CuB(OMe)2 reacted with ethylene and diphenylacetylene to provide insertion compounds into the Cu-B bond which were characterised by NMR spectroscopy in both cases and X-ray crystallography in the latter. It was also competent in the rapid catalytic deoxygenation of CO2 in the presence of excess B2(OMe)4. Alongside π-insertion, (6-Dipp)CuB(OMe)2 reacted with LiNMe2 to provide a salt metathesis reaction at boron, giving (6-Dipp)CuB(OMe)NMe2, a second monomeric acyclic boryl, which also cuproborated diphenylacetylene. Computational interrogation validated these acyclic boryl species to be electronically similar to (6-Dipp)CuBpin.
Stereoselective Synthesis of Allylic Alcohols via Substrate Control on Asymmetric Lithiation
Allylic alcohols are a privileged motif in natural product synthesis and new methods that access them in a stereoselective fashion are highly sought after. Toward this goal, we found that chiral acetonide-protected polyketide fragments performing the Hoppe–Matteson–Aggarwal rearrangement in the absence of sparteine with high yields and diastereoselectivities rendering this protocol a highly valuable alternative to the Nozaki–Hiyama–Takai–Kishi reaction. Various stereodyads and -triads were investigated to determine their substrate induction. The mostly strong inherent stereoinduction was attributed to a combination of steric and electronic effects.
[ASAP] Nickel-Catalyzed Functionalization Reactions Involving C–H Bond Activation via an Amidate-Promoted Strategy and Its Extension to the Activation of C–F, C–O, C–S, and C–CN Bonds
Accounts of Chemical Research
DOI: 10.1021/acs.accounts.3c00493
[ASAP] Base-Stacking-Driven Catalytic Hairpin Assembly: A Nucleic Acid Amplification Reaction Using Electrode Interface as a “Booster” for SARS-CoV-2 Point-of-Care Testing
Analytical Chemistry
DOI: 10.1021/acs.analchem.3c02577
Advances in Continuous Flow Fluorination Reactions
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.
Photocatalyst‐ and Transition Metal‐Free Light‐Induced Borylation Reactions
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.
Photoinduced Reactions of Styrylpyridine Derivatives for the In Situ Formation of Selective Ligands for Apyrimidinic DNA
The photoreaction of a styrylpyridine derivative leads to a DNA-binding benzoquinolizinium derivative with selectivity towards abasic site-containing DNA (AP-DNA), as caused by the sterically demanding substituents. Notably, the DNA binding is accomplished by photoinduced in situ formation of the ligand in the presence of AP-DNA.
Abstract
The photocyclization reaction of sterically demanding styrylpyridine derivatives was investigated and shown to depend on the type of substituent. With this method, a 2,2-diphenyl-1,3-benzodioxolo-annelated benzo[c]quinolizinium was synthesized, and its association with regular and abasic site-containing DNA (AP-DNA) was investigated by absorption, fluorescence, circular and linear dichroism spectroscopy. Specifically, this ligand binds preferentially to AP-DNA relative to regular duplex DNA, and the AP-DNA/ligand complex is formed in situ upon irradiation of the styrylpyridine substrate in the presence of the DNA.