An Unprecedented [BO2]‐Based Deep‐Ultraviolet Transparent Nonlinear Optical Crystal by Superhalogen SubstitutionLiu, Shuai; Jiang, Xingxing; Qi, Lu; Hu, Yilei; Duanmu, Kaining; Wu, Chao; Lin, Zheshuai; Huang, Zhipeng; Humphrey, Mark G.; Zhang, Chi
doi: 10.1002/anie.202403328pmid: 38662352
Solid‐state structures with the superhalogen [BO2]− have thus far only been observed with a few compounds whose syntheses require high reaction temperatures and complicated procedures, while their optical properties remain almost completely unexplored. Herein, we report a facile, energy‐efficient synthesis of the first [BO2]‐based deep‐ultraviolet (deep‐UV) transparent oxide K9[B4O5(OH)4]3(CO3)(BO2) ⋅ 7H2O (KBCOB). Detailed structural characterization and analysis confirm that KBCOB possesses a rare four‐in‐one three‐dimensional quasi‐honeycomb framework, with three π‐conjugated anions ([BO2]−, [BO3]3−, and [CO3]2−) and one non‐π‐conjugated anion ([BO4]5−) in the one crystal. The evolution from the traditional halogenated nonlinear optical (NLO) analogues to KBCOB by superhalogen [BO2]− substitution confers deep‐UV transparency (<190 nm), a large second‐harmonic generation response (1.0×KH2PO4 @ 1064 nm), and a 15‐fold increase in birefringence. This study affords a new route to the facile synthesis of functional [BO2]‐based oxides, paving the way for the development of next‐generation high‐performing deep‐UV NLO materials.
tert‐Butyl as a Functional Group: Non‐Directed Catalytic Hydroxylation of Sterically Congested Primary C−H BondsChan, Siu‐Chung; Palone, Andrea; Bietti, Massimo; Costas, Miquel
doi: 10.1002/anie.202402858pmid: 38688859
The tert‐butyl group is a common aliphatic motif extensively employed to implement steric congestion and conformational rigidity in organic and organometallic molecules. Because of the combination of a high bond dissociation energy (~100 kcal mol−1) and limited accessibility, in the absence of directing groups, neither radical nor organometallic approaches are effective for the chemical modification of tert‐butyl C−H bonds. Herein we overcome these limits by employing a highly electrophilic manganese catalyst, [Mn(CF3bpeb)(OTf)2], that operates in the strong hydrogen bond donor solvent nonafluoro‐tert‐butyl alcohol (NFTBA) and catalytically activates hydrogen peroxide to generate a powerful manganese‐oxo species that effectively oxidizes tert‐butyl C−H bonds. Leveraging on the interplay of steric, electronic, medium and torsional effects, site‐selective and product chemoselective hydroxylation of the tert‐butyl group is accomplished with broad reaction scope, delivering primary alcohols as largely dominant products in preparative yields. Late‐stage hydroxylation at tert‐butyl sites is demonstrated on 6 densely functionalized molecules of pharmaceutical interest. This work uncovers a novel disconnection approach, harnessing tert‐butyl as a potential functional group in strategic synthetic planning for complex molecular architectures.
Sucrose‐Powered Liposome Nanosensors for Urinary Glucometer‐Based Monitoring of CancerZhou, Dongtao; Zhang, Zhibin; Pan, Liqing; Wang, Yanyi; Yang, Jingjing; Gao, Yanfeng; Song, Yujun
doi: 10.1002/anie.202404493pmid: 38687277
Timely detection of early‐stage cancer holds immense potential in enhancing prognostic outcomes. There is an increasing desire for versatile tools to enable simple, sensitive, and cost‐effective cancer detection. By exploiting the extraintestinal metabolic inertness and efficiency renal clearance of sucrose, we designed a liposome nanosensor using sucrose as a messenger to convert tumor‐specific esterase activity into glucose meter readout, enabling economical and sensitive urinalysis for cancer detection in point‐of‐care testing (POCT). Our results demonstrate that the nanosensors exhibited significant signal differences between tumor‐bearing and healthy mice in both orthotopic and metastatic tumor models. Additionally, efficient elimination of the nanosensors through the hepatobiliary pathway was observed with no significant toxicity. Such a non‐invasive diagnostic modality significantly assists in personalized pharmacological treatment and follow‐up efficacy assessment. We envision that this modular liposome nanosensor platform might be applied for economically detecting diverse diseases via a simple urinary test.
Solvation Properties of Neutral Gold Species in Supercritical Water Studied By THz SpectroscopyNoetzel, Jan; Schienbein, Philipp; Forbert, Harald; Marx, Dominik
doi: 10.1002/anie.202402120pmid: 38695846
Supercritical water provides distinctly different solvation properties compared to what is known from liquid water. Despite its prevalence deep in the Earth's crust and its role in chemosynthetic ecosystems in the vicinity of hydrothermal vents, molecular insights into its solvation mechanisms are still very scarce compared to what is known for liquid water. Recently, neutral metal particles have been detected in hydrothermal fluids and proposed to explain the transport of gold species to ore deposits on Earth. Using ab initio molecular dynamics, we elucidate the solvation properties of small gold species at supercritical conditions. The neutral metal clusters themselves contribute enormous THz intensity not because of their intramolecular vibrations, but due to their pronounced electronic polarization coupling to the dynamical supercritical solvent, leading to a continuum absorption up to about 1000 cm−1. On top, long‐lived interactions between the gold clusters and solvation water leads at these supercritical conditions to a sharp THz resonance that happens to be close to the one due to H‐bonding in liquid water at ambient conditions. The resulting distinct resonances can be used to analyse the solvation properties of neutral metal particles in supercritical aqueous solutions.
Formation of a Porous Crystalline Mg1‐xAl2Oy Overlayer on Metal Catalysts via Controlled Solid‐State Reactions for High‐temperature Stable CatalysisCai, Lihua; Han, Shanlei; Xu, Wenlong; Chen, Si; Shi, Xianxian; Lu, Junling
doi: 10.1002/anie.202404398pmid: 38698730
Catalyst deactivation by sintering and coking is a long‐standing issue in metal‐catalyzed harsh high‐temperature hydrocarbon reactions. Ultrathin oxide coatings of metal nanocatalysts have recently appeared attractive to address this issue, while the porosity of the overlayer is difficult to control to preserve the accessibility of embedded metal nanoparticles, thus often leading to a large decrease in activity. Here, we report that a nanometer‐thick alumina coating of MgAl2O4‐supported metal catalysts followed by high‐temperature reduction can transform a nonporous amorphous alumina overlayer into a porous Mg1‐xAl2Oy crystalline spinel structure with a pore size of 2–3 nm and weakened acidity. The high porosity stems from the restrained Mg migration from the MgAl2O4 support to the alumina overlayer through solid‐state reactions at high temperatures. The resulting Ni/MgAl2O4 and Pt/MgAl2O4 catalysts with a porous crystalline Mg1‐xAl2Oy overlayer achieved remarkably high stability while preserving much higher activity than the corresponding alumina‐coated Ni and Pt catalysts on MgO and Al2O3 supports in the reactions of dry reforming of methane and propane dehydrogenation, respectively.
Synthesis of Unsymmetrical Trisulfides from S‐Substituted SulphenylthiosulphatesLiang, Shuaishuai; Ma, Liye; Guo, Zihao; Liu, Fanmin; Lin, Zijian; Yi, Wenbin
doi: 10.1002/anie.202404139pmid: 38689425
Trisulfide unit is widely found in natural products and has garnered attention due to the unique pharmacological and physiochemical properties. However, despite limited progress, widely applicable approaches for constructing unsymmetrical trisulfides have so far remain scarce. In this work, an easy‐to‐prepare, solid‐state and scalable reagent, S‐substituted sulphenylthiosulphate, has been developed for the divergent synthesis of unsymmetrical trisulfides. Alkyl electrophile substrates, including bromides, chlorides, iodides and tosylates, with diverse substituents are smoothly converted to the corresponding trisulfides with S‐substituted sulphenylthiosulphates and thiourea as another sulfur source. Furthermore, the late‐stage modification of drug molecules was successfully achieved through this method.