RESUMEN
A novel bimetal cluster [Au28Cu12(SR)24](PPh4)4 (SR = 2,4-dichlorothiophenol) has been successfully synthesized, which can be viewed as a Au4@Au24 core and four trimeric Cu3(SR)6 staples. Compared to monometallic Au28(TBBT)20 and Cu28(CHT)18(PPh3)3 clusters, the [Au28Cu12(C6H4Cl2S)24](PPh4)4 cluster has much higher catalytic efficiency for nitrate electroreduction to ammonia.
RESUMEN
Here we report a diachronic evolvement from tetra-icosahedral Au30Ag12(C[triple bond, length as m-dash]CR)24 to quasi-hcp (hexagonal close-packed) Au47Ag19(C[triple bond, length as m-dash]CR)32 via a one-step reduction, in which the size/structure conversion of the two clusters is not a typical Oswald growth process, but involves interface shrinking followed by core rearrangement and surface polymerization. Au30Ag12(C[triple bond, length as m-dash]CR)24 has an aesthetic Au18Ag8 kernel that is composed of four interpenetrating Au10Ag3 icosahedra, while Au47Ag19(C[triple bond, length as m-dash]CR)32 has a twisted Au19 core capped by a Au12Ag19 shell that are stacked in a layer-by-layer manner with a quasi-hcp pattern. The discovery of the two clusters not only provides further evidence for icosahedral clusters with longer excited-state lifetime compared to hcp-like clusters, but also discloses a double increase in catalytic reactivity for electrocatalytic oxidation of ethanol over quasi-hcp clusters in comparison with icosahedral clusters. This work provides the rationale for reversing the bottom-up growth process to remake bimetal clusters.
RESUMEN
A novel Ag doped Au44 (C10 H9 )28 nanocluster (C10 H10 =1-ethynyl-2,4-dimethylbenzene) was synthesized, that is, Ag4+x Au40-x (C10 H9 )28 (x≤6), where four Ag positions located in the surface staple of the cluster have been determined, while six Au/Ag co-occupying positions have been found in the metal core of the cluster. The electronic configuration of Au44 (C10 H9 )28 cluster is significantly disturbed by doping Ag atoms, hence promoting the electron transport capability. For the two-electron conversion reaction of CO2 to CO in electrochemical reduction of CO2 , Ag doped Ag4+x Au40-x (C10 H9 )28 catalyst exhibited higher effective activity and long-term stability than its counterpart Au44 (C10 H9 )28 catalyst.
RESUMEN
Hierarchical assembly of nanoparticles has been attracting wide interest, as advanced functionalities can be achieved. However, the ability to manipulate structural evolution of artificial nanoparticles into assemblies with atomic precision has been largely unsuccessful. Here we report the evolution from monomeric Au24Au20 into dimeric Au43Ag38 nanoclusters: Au43Ag38 inherits the kernel frameworks from parent Au24Ag20 but exhibits distinct surface motifs; Au24Ag20 is racemic, while Au43Ag38 is mesomeric. Importantly, the evolution from monomers to dimers opens up exciting opportunities exploring currently unknown properties of monomeric and dimeric alloy nanoclusters. The Au24Ag20 clusters show superatomic electronic configurations, while Au43Ag38 clusters have molecular-like characteristics. Furthermore, monomeric Au24Ag20 catalysts readily outperform dimeric Au43Ag38 catalysts in the catalytic reduction of CO2.
RESUMEN
Since the introduction of computed tomography (CT), detection of small lung cancer, especially small peripheral adenocarcinoma, is common. Recently, the morphological characteristics, including thin-section CT and pathologic findings, and prognosis of small peripheral lung adenocarcinomas have been studied extensively. The radiologic and microscopic findings correlate well with each other and are closely associated with tumour prognosis. Most importantly, some subtypes of small lung adenocarcinomas with specific CT or pathologic features are curable. Therefore, all defining characteristics (CT, pathologic and prognostic) of this kind of tumour should be integrated to improve our understanding, provide guidelines for management and accurately assess its prognosis.