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We report the first diselenide‐based probe for the selective detection of thioredoxin reductase (TrxR), an enzyme commonly overexpressed in melanomas. The probe design involves conjugation of a seminaphthorhodafluor dye with a diselenide moiety. TrxR reduces the diselenide bond, triggering a fluorescence turn‐on response of the probe. Kinetic studies reveal favorable binding of the probe with TrxR with a Michaelis‐Menten constant (K m ) of 15.89 µM. Computational docking simulations predict a greater binding affinity to the TrxR active site in comparison to its disulfide analogue. In vitro imaging studies further confirmed the diselenide probe exhibited improved signaling of TrxR activity compared to the disulfide analogue.
Intersystem crossing (ISC) of triplet photosensitizers is a vital process for fundamental photochemistry and photodynamic therapy (PDT). However, the currently effective long wavelength operating photosensitizers have to rely on heavy atoms to enhance ISC. Unfortunately, the heavy atoms, besides their toxicity, can also cause significant reduction in the triplet lifetime of the photosensitizers, which is fundamentally detrimental to their applications. To overcome this challenge, herein we report the co‐existence of efficient ISC and long triplet excited lifetime in a heavy atom‐free Bodipy helicene molecule. Via advanced theoretical computation and time‐resolved electron paramagnetic resonance spectroscopy, we confirmed the ISC of the Bodi.
Reticular materials are of high interest for diverse applications ranging from catalysis and separation to gas storage and drug delivery. These open, extended frameworks can be tailored to the intended application through crystal structure design. Implementing these materials in application settings, however, requires structuring beyond their lattices, in order to interface the functionality at the molecular level effectively with the macroscopic world. To overcome this barrier, efforts in expressing structural control across molecular, nano, meso, and bulk regimes is the essential next step. In this minireview, we discuss recent advances in using self‐assembly as well as externally controlled tools to manufacture reticular materials throug.
Halide perovskites show incredible photovoltaic power conversion efficiency coupled with several hundreds of hours of device stability for finely tuned material compositions. It is expected to employ such a successful photovoltaic material in (photo)electrochemical(PEC) systems, including solar water splitting. However their stability is very poor in aqueous electrolyte medium and they decompose instantly, which limits their use in PEC systems. Here we report a vacancy ordered halide perovskite, Cs 2 PtI 6 , which shows extraordinary stability in ambient (1 year), aqueous medium of extreme acidic (pH 1), basic (pH 13) and electrochemical reduction conditions. We investigated their electrochemical and photoelectrochemical redox processes und.
The hetero‐arylation of alkenes with aryl iodides has been efficiently achieved with the (MeDalphos)AuCl complex via Au(I)/Au(III) catalysis. The possibility to combine oxidative addition of aryl iodides and π‐activation of alkenes at gold is demonstrated for the first time. The reaction is robust and general (>30 examples including internal alkenes, 5, 6 and 7‐membered rings). It is regioselective and leads exclusively to trans addition products. The (P,N) gold complex is most efficient with electron‐rich aryl substrates, which are troublesome with alternative photoredox / oxidative approaches. In addition, it actuates a very unusual switch in regioselectivity from 5‐exo to 6‐endo cyclization between the Z and E isomers of internal alkenol.
A novel Ni/Cu dual catalysis gives rise to fundamentally new cooperative reactivity and enables the regio‐ and enantioselective propargylic alkylation reaction. A diverse set of α‐quaternary propargylated amino ester derivatives were synthesized in good yields with excellent enantioselectivities (up to 99% ee ). This work highlights the power of cooperative catalysis, which can be expected to have broad implications in homogeneous catalysis beyond the highly valuable synthetic intermediates.
The impact of a reactant from the gas phase on the surface of a liquid and its transfer through this gas/liquid interface are crucial for various concepts applying ionic liquids (ILs) in catalysis. We investigated the first step of the adsorption dynamics of n‐butane on a series of 1‐alkyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide ILs ([C n C 1 Im][Tf 2 N]; n = 1, 2, 3, 8). Using a supersonic molecular beam in ultra‐high vacuum, the trapping of n‑butane on the frozen ILs was determined as a function of surface temperature, between 90 and 125 K. On the C 8 ‐ and C 3 ‐ILs, n‐butane adsorbs at 90 K with an initial trapping probability of ~0.89. The adsorption energy increases with increasing length of the IL alkyl chain, whereas t.
Stable operation at elevated temperature is necessary for lithium (Li) metal anode as the promising anode for next‐generation batteries in diversified scenarios. However, Li metal anode generally undergoes poor performances and even safety concerns at high temperature (> 55°C) due to the thermal instability of electrolyte and solid electrolyte interphase in a routine liquid electrolyte. Herein a Li metal anode working at an elevated temperature of 90°C is demonstrated in a thermal‐stable electrolyte. In Li | LiFePO4 battery working at 90°C, Li metal anode undergoes 100 cycles compared with 10 cycles in a practical carbonate electrolyte. During the formation of solid electrolyte interphase, the independent and incomplete decomposition of Li
Complex structures from nanoparticles are found in rocks, soils, and sea sediments but the mechanisms of their formation are poorly understood. It is shown that graphene quantum dots (GQDs) can assemble into complex structures driven by coordination interactions with metal ions commonly present in the environment and play a special role in Earth's history, such as Fe3+ and Al3+. Abstract. Complex structures from nanoparticles are found in rocks, soils, and sea sediments but the mechanisms of their formation are poorly understood, which causes controversial conclusions about their genesis. Here we show that graphene quantum dots (GQDs) can assemble into complex structures driven by coordination interactions with metal ions commonly present in.
Straight shot: A direct γ‐C−H olefination of carboxylic acids and subsequent intramolecular cyclization generates δ‐lactones. Two suitable ligand classes are identified to enable this Pd‐catalyzed transformation that features a broad scope of both reaction partners. The reaction does not require an exogenous directing group and can be performed on a synthetically useful scale. Kinetic studies provide first mechanistic insights. Abstract. We report the ligand‐enabled C−H activation/olefination of free carboxylic acids in the γ‐position. Through an intramolecular Michael addition, δ‐lactones are obtained as products. Two distinct ligand classes are identified that enable the challenging palladium‐catalyzed activation of free carboxylic acids i.
Lithium bonds that are present in lithium batteries are discussed in this Viewpoint, including historical developments, comparisons with hydrogen bonds, and their potential applications. Discourse on the chemistry of the Li bond can provide fruitful insight into the fundamental interactions within Li batteries and thus deliver a deeper understanding of their working mechanism. Abstract. Lithium bonds are analogous to hydrogen bonds and are therefore expected to exhibit similar characteristics and functions. Additionally, the metallic nature and large atomic radius of Li bestow the Li bond with special features. As one of the most important applications of the element, Li batteries afford emerging opportunities for the exploration of Li bond
A transition‐metal‐free method for the synthesis of α‐branched amines from tertiary carboxamides and lactams with carbon‐centered nucleophiles has been developed. This scalable process relies on the controlled reduction of tertiary amides by NaH/NaI composite, in situ treatment of the resulting anionic hemiaminal with trimethylsilyl chloride, and subsequent coupling with nucleophilic reagents including Grignard reagents and tetrabutylammonium cyanide. Abstract. A new method for the synthesis of α‐branched amines by reductive functionalization of tertiary carboxamides and lactams is described. The process relies on the efficient and controlled reduction of tertiary amides by a sodium hydride/sodium iodide composite, in situ treatment of the r.
A catalytic diastereo‐ and enantioselective method for the preparation of complex tertiary homoallylic alcohols containing a vicinal quaternary carbon stereogenic center and a versatile alkenylboronic ester is disclosed. The reactions are catalyzed by a chiral Cu complex and proceed with a wide variety of ketones and γ,γ‐disubstituted allylic diboronates to afford products in high dr and er. Abstract. A catalytic diastereo‐ and enantioselective method for the preparation of complex tertiary homoallylic alcohols containing a vicinal quaternary carbon stereogenic center and a versatile alkenylboronic ester is disclosed. Transformations are promoted by 5 mol % of a readily available copper catalyst bearing a bulky monodentate phosphoramidite li.
Cage PAINTings: Fluorescent DNA probes conjugated with a cyanine dye are reductively caged to hydrocyanine, acting as a photoactivatable dark state. The additional dark state from caging lowered the fluorescent background while enabling optically selective activation by total internal reflection illumination. With the aid of high‐density analysis, the imaging speed of conventional DNA‐PAINT was increased by two orders of magnitude, making DNA‐PAINT capable of high‐throughput super‐resolution imaging. Abstract. In DNA points accumulation in nanoscale topography (DNA‐PAINT), capable of single‐molecule localization microscopy with sub‐10‐nm resolution, the high background stemming from the unbound fluorescent probes in solution limits the imagi.
A chemical robot was designed, assembled and utilised for the discovery of supramolecular architectures through the exploration of a chemical space exceeding 109 possible reactions. By searching for reactivity differences, a range of new 1‐benzyl‐(1,2,3‐triazol‐4‐yl)‐N‐alkyl‐(2‐pyridinemethanimine) ligands were found and four new complexes of Fe and Co were discovered, autonomously discovering the rules of self‐assembly for these systems. Abstract. We present a chemical discovery robot for the efficient and reliable discovery of supramolecular architectures through the exploration of a huge reaction space exceeding ten billion combinations. The system was designed to search for areas of reactivity found through autonomous selection of the re.
It has been long‐pursued but remains great challenge to precisely manipulate the molecule assembly process to have desired functional structures. Here, we report such a control over the assembly of solute molecules, via a programmed recrystallization of solvent crystal grains, to form micro/nano‐ particles with tunable sizes and crystalline forms. A quantitative correlation between the protocol of recrystallization temperature and the assembly kinetics results in the precise control over the size of assembled particles, ranging from single‐atom catalysts, pure drug nanoparticles to sub‐millimeter organic‐semiconductor single crystals. The extensive regulation of the assembly rates leads to the unique and powerful capability in tuning the st.
The heat is on: Supramolecular self‐assembly of two water‐soluble phthalocyanine derivatives forms a nanostructured contrast agent, which displays improved photoacoustic and photothermal properties. Abstract. Phototheranostic nanoplatforms are of particular interest for cancer diagnosis and imaging‐guided therapy.
Carbon‐bridged oligo(phenylenevinylene) (COPV2)–carbazole core–shell dendrimers with molecular weight as large as 4600 g mol−1 form microcrystals in which dendrons and COPV2 work as light‐harvesting antenna and fluorophore, respectively. The microcrystals function as a laser resonator, where the light confinement mode tightly couples with the alignment of the dendrimers and the morphology of the crystals. Abstract. Microcrystallites are promising minute mirrorless laser sources. A variety of luminescent organic compounds have been exploited along this line, but dendrimers have been inapplicable owing to their fragility and extremely poor crystallinity. Now, a dendrimer family that overcomes these difficulties is presented. First‐, second‐, a.
Here we disclose a cobaloxime‐catalyzed acceptorless dehydrogenative cyclization of o ‐teraryls. In stark contrast to the established methods such as the Scholl or Mallory reactions, this protocol does not require any strong acids or oxidants, showing high atom economy and a broad substrate scope. It operates at near room temperature with light as the source of energy. Acid or oxidant‐sensitive functional groups, such as 4‐methoxyphenyl, unprotected benzyl alcohol, silyl ether and thiophene, are tolerated. Remarkably, aryls with electron‐withdrawing groups and electron‐poor heteroarenes, such as pyridine and pyrimidine, can also react. Preliminary mechanistic study reveals that hydrogen gas is released during the reaction, and both light an.

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