Enhancement of catalytic activity for hydrogenation of nitroaromatic by anionic metal-organic framework

Nitroaromatic hydrogenation catalysis without precious metals remains a longstanding challenge.The rate of electron transfer is the crucial factor affecting hydrogenation catalysis.Herein,an ionic Cd-based metal-organic framework(I-Cd-MOF)exhibiting a unique structure with one-dimensional(1D)opening nanochannels and good electron transfer ability was synthesized for catalyzing hydrogenation of 4-nitrophenol(4-NP).The catalytic activity of the unique I-Cd-MOF without noble metals is detected,which is higher than most reported noble metal catalysts.Remarkably,the reaction rate of I-Cd-MOF(4.28 min^(-1))is about 47.6 times higher than that of the Cd-based neutral MOF(N-Cd-MOF)with the similar crystalline structure.Liquid chromatograph mass spectrometer(LC-MS)and theoretical results demonstrate that 4-NP and five intermediates are stabilized in the channels of I-Cd-MOF,which increases the possibility of contact with H^*and H_(2)g enerated at the Cd sites.The I-Cd-MOF was extended to other nitroaromatic hydrogenation catalysis,which still displays excellent activity.More importantly,the I-MOF@Filter membrane was successfully constructed for continuous hydrogenation catalytic reactions,which maintains a high catalytic performance after 7 cycles of recycling without washing.This work fills in the application of the I-MOFs in hydrogenation catalytic reactions and provides an effective way for the rapid and green degradation of nitroaromatic compounds.

N-Heterocyclic carbene-stabilized platinum nanoparticles within a porphyrinic nanocage for selective photooxidation

The successful construction of highly stable and active platinum nanoparticles(Pt NPs) within the confined cavity of a threedimensional porphyrinic nanocage is presented in this study. The flexible porphyrinic nanocage containing eight N-heterocyclic carbene(NHC) precursors was prepared using a metal-carbene-templated ring-closing metathesis(RCM) approach as new capping materials for the fabrication/stabilization of Pt NPs. Notably, the NHC-stabilized Pt NPs within the porphyrinic nanocage exhibited high catalytic activity for selective oxidation of 2-chloroethyl ethyl sulfide to nontoxic 2-chloroethyl ethyl sulfoxide with excellent stability and recyclability.

Template Synthesis of Metal Nanoparticles within Organic Cages

Background Metal nanoparticles(M-NPs)have attracted tremendous interest in recent years due to their unique physical and chemical properties resulting from their size reduction and shape variation.[1]In particular,the use of ultra-small M-NPs as efficient catalysts in various reactions is a rapidly growing area of research as a consequence of their synthetic accessibility and superior catalytic efficiency.[2]However,due to their high surface energy,small M-NPs are prone to aggregation during reactions and associated loss of their catalytic activities.To deal with this difficulty,various stabilizers and/or supports have been developed,for instance,small organic ligands,dendritic architectures,and polymers.Unfortunately,these materials all have limitations,such as low stability,constant leaching,irregular distribution or regrowth and combinations of these.Therefore,it is highly desirable to develop superior support materials that can overcome these issues.

Highly flexible ceramic nanofibrous membranes for superior thermal insulation and fire retardancy

Ceramic membranes are attractive for thermal management applications due to its lightweight and ultralow thermal conductivity,while it is indispensable to address the long-standing obstacle of its poor mechanical stability and degradation under thermal shock.In this work,a series of the organic polymer template-modulated yttria doped zirconia(YDZ)nanofibrous membranes with lightweight,superior mechanical and thermal stability are developed through a cost-effective,scalable sol-gel electrospinning and subsequent calcination method.The YDZ membranes demonstrate excellent flexibility and foldability,which can be attributed to the tetragonal phase and small crystallite size of the YDZ fibers due to the presence of yttria.Besides,the fibrous size,grain size,mechanical and thermal stability of YDZ nanofibrous membranes could be tailored by varying the species and molecular weight of polymer template.The remarkable performances are obtained through the poly(vinyl pyrrolidone)(PVP)template YDZ nanofibrous membranes,featuring the superior tensile strength up to~4.82 MPa,excellent flexibility with bending rigidity~26 mN,robust thermal stability up to 1,200℃,ultra-low thermal conductivity of 0.008–0.023 W·m^(−1)·K^(−1)(25–1,000℃),and excellent flame retardancy with tolerance of flame up to 1,000℃.The remarkable properties can be attributed to the smaller fibrous size,and higher grain size resulting from PVP template.This robust material system is ideal for thermal superinsulation with a wide range of uses from energy saving building applications to spacecraft.

Two comparable Ba-MOFs with similar linkers for enhanced CO_(2)capture and separation by introducing N-rich groups

Two new different metal-organic frameworks(MOFs)[Ba(L1)(H_(2)O)_(2)]_(n)·nH_(2)O(MOF 1)and[Ba(L2)(-n2 O)_(2)]_(n)·0.5 nDMF·0.5 nH_(2)O(MOF 2)were yielded by the assembly of oxygen-friendly Ba(Ⅱ)ions and two similar linkers,namely 2-(imidazol-1-yl)terephthalic acid(H_(2)L1)and 2-(1 H-1,2,4-triazol-1-yl)terephthalic acid(H_(2)L2).Single-crystal X-ray diffractions(XRD)indicate that MOF1 is a new three-dimensional(3 D)stacking dense network formed by the one-dimensional(1 D)rod-shaped chains and L1 linkers,whereas MOF 2 presents a 3 D nanotube porous framework with cylindrical tunnels based on the 1 D loop chains as the secondary building units(SBUs)by replacing the imidazole group in H_(2)L1 with the triazole group in H_(2)L2.As a result,MOF 2 has a higher density of active sites and Lewis acid sites in the porous surface of nanotube than MOF 1.Thereby,the CO_(2)capture and separation capacity of MOF 2 is great higher than that of CH_(4)at298 K.

Phase-mediated controllable intramolecular and intermolecular photocycloadditions assisted by supramolecular templates

Understanding and controlling supramolecular template effect assembly via a photochemical reaction in different solid and solution phases is one of the main topics in photochemistry. Here, an interesting case of phase-mediated controllable intramolecular/intermolecular photochemical [2+2] cycloadditions assisted by supramolecular templates was demonstrated. Direct irradiation of the complexes in solution yields intramolecular photoproducts exclusively, whereas exposure of the solid powder sample under the same conditions yields intermolecular dinuclear species quantitatively. The nature of the phase and supramolecular interaction affects the geometrical arrangements of the metallacycles, leading to different cycloaddition products under photoirradiation. The crystal structures of different products were investigated by single-crystal X-ray diffraction, nuclear magnetic resonance(NMR) spectrometry, and electrospray ionization mass spectrometry(ESI-MS).

PhI(OAc)2-promoted umpolung acetoxylation of enamides for the synthesis of α-acetoxy ketones

Umpolung is a fundamental concept in organic chemistry, which provides an alternative strategy for the synthesis of target compounds which were not easily accessible by conventional methods. Herein, a mild and efficient PhI(OAc)_2-promoted umpolung acetoxylation reactions of enamides was developed for the synthesis of α-acetoxy ketones. The reaction tolerates a wide range of functional groups and affords α-acetoxy ketones in good to excellent yields. PhI(OAc)_2 serves as a source of acetoxy in the reaction.

Base-mediated formal [3＋2] cycloaddition of β,γ-alkenyl esters and p-TsN3 for the synthesis of pyrazoles

A novel 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU)-mediated formal cycloaddition of β,γ-alkenyl esters with p-tolylsulfonylazide(p-TsN_3) for the synthesis of 3,5-disubstituted pyrazoles has been developed.The reaction proceeded through diazotization of β,γ-alkenyl esters sequential with thermodynamic cyclization.p-Tolylsulfonylazide played a role as a source of two-nitrogen synthons.The reaction employs readily available starting materials,tolerates a wide range of functional groups,and proceeds under mild conditions.

Dramatic Impact of Auxiliary Ligands on the Dynamic Magnetic Relaxation in Tetranuclear Dy^(III)_(2)Zn^(II)_(2) Single Molecule Magnets

Better understanding the determining factors of dynamic magnetic relaxation in polynuclear lanthanide based single-molecule magnets(SMMs)remains a challenge due to the complexity of such architectures involving interactions between the magnetic centers.To address this issue,two structurally related heterometal Dy^(III)_(2)Zn^(II)_(2) SMMs,[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)(CH_(3)OH)]·CH_(3)OH·2H_(2)O(1)and[Zn_(2)Dy_(2)(L)_(4)(Ac)_(2)(DMF)_(2)]·4CH_(3)CN(2)(H_(2)L=(E)-2-((2-hydroxy-3-methoxybenzylidene)amino)-4-methyphenol,DMF=N,N-dimethylformamide),are introduced and investigated.Through modifying the auxiliary ligands on one Dy^(III) site while retaining that on the other Dy^(III),the intramolecular magnetic interactions and relaxation dynamics in these two heterometallic-Dy^(III)_(2)Zn^(II)_(2) SMMs can be tuned,demonstrating a dramatic change in the magnet relaxation behavior with energy barrier changing from a negligible value for 1 to 305 K for 2.Ab initio calculations reveal that changing the coordination geometries on the Dy^(III) sites can significantly affect the magnetic interactions as well as single-ion anisotropy.

Biomimetic design of highly flexible metal oxide nanofibrous membranes with exceptional mechanical performance for superior phosphopeptide enrichment

Developing free-standing and mechanical robust membrane materials capable of superior enrichment of phosphopeptides for analyzing and identifying the specific phosphoproteome of cancer cells is significant in understanding the molecular mechanisms of cancer development and exploring new therapeutic approaches,but still a significant challenge in materials design.To this end,we firstly constructed highly flexible ZrTiO_(4) nanofibrous membranes(NFMs)with excellent mechanical stability through a cost-effective and scalable electrospinning and subsequent calcination technique.Then,to further increase the enrichment capacity of the phosphopeptide,the biomimetic TiO_(2)@ZrTiO_(4) NFMs with root hair or leaf like branch microstructure are developed by the hydrothermal post-synthetic modification of ZrTiO_(4) NFMs through growing unfurling TiO_(2) nanosheets onto the ZrTiO_(4) nanofibers.Importantly,remarkable flexibility and mechanical stability enable the resulting TiO_(2)@ZrTiO_(4) NFMs excellent practicability,while the biomimetic microstructure allows it outstanding enrichment ability of the phosphopeptide and identification ability of the specific phosphoproteins in the digest of cervical cancer cells.Specifically,6770 phosphopeptides can be enriched by TiO_(2)@ZrTiO_(4) NFMs(2205 corresponding phosphoproteins can be identified),and the value is much higher than that of ZrTiO_(4) NFMs(6399 phosphopeptides and 2132 identified phosphoproteins)and commercial high-performance TiO_(2) particles(4525 phosphopeptides and 1811 identified phosphoproteins).These results demonstrate the super ability of TiO_(2)@ZrTiO_(4) NFMs in phosphopeptide enrichment and great potential for exploring the pathogenesis of cancer.

A robust indium-organic framework with open tubular channels for efficient separation of acetylene

Considering the tremendous applications and purification requirement of acetylene(C_(2)H_(2)),seeking appropriate adsorbents with high capacity and selectivity is a vital task and remains an enduring challenge.Herein,we designed and synthesized a robust three-dimensional(3D)indium-organic framework([(Me)_(2)NH_(2)][In(L6)_(0.5)(IPA)_(0.5)]·DMA·2H_(2)O(In-L6-IPA,DMA=dimethylammonium,IPA=isopropyl alcohol))featuring two types of one-dimensional(1D)tubular channels.The activated In-L6-IPA displayed high loading for C_(2)H_(2)(104.4 cm^(3)·g^(-1),the second highest value among all reported indium-based metal-organic frameworks(MOFs))and simultaneously selective adsorption for C_(2)H_(2) over CO_(2),C_(2)H_(6),and ethylene(C_(2)H_(4))at 298 K under 100 kPa.Molecular modelling revealed that the porous wall of In-L6-IPA provides more and stronger multiple interactions for C_(2)H_(2) than CO_(2),C_(2)H_(6),and C_(2)H_(4) containing C–H···π,C–H···O,and O···πinteractions.Breakthrough experiments validated the actual separation ability for various ratios of binary C_(2)H_(2)/C_(2)H_(4) and C_(2)H_(2)/CO_(2) mixtures as well as equimolar ternary C_(2)H_(2)/C_(2)H_(4)/CO_(2) and C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6) mixtures with excellent reusability.

Erratum to: A robust indium-organic framework with open tubular channels for efficient separation of acetylene

Erratum to Nano Research,2024,17(4):3139–3146 https://doi.org/10.1007/s12274-023-6061-8 In the first page of the original version of this paper,the corresponding authors should be“Yanwei Sui”and“Lei Hou”,instead of“Lei Hou”and“Yao-Yu Wang”.And“Address correspondence to:Lei Hou,lhou2009@nwu.edu.cn;Yao-Yu Wang,wyds123456@outlook.com”should be corrected to“Address correspondence to:Lei Hou,lhou2009@nwu.edu.cn;Yanwei Sui,wyds123456@outlook.com”.