0000000001306508
AUTHOR
Hui Shen
Highly Robust but Surface-Active : An N-Heterocyclic Carbene-Stabilized Au25 Nanocluster
Surface organic ligands play a critical role in stabilizing atomically precise metal nanoclusters in solutions. However, it is still challenging to prepare highly robust ligated metal nanoclusters that are surface-active for liquid-phase catalysis without any pre-treatment. Now, an N-heterocyclic carbene-stabilized Au25 nanocluster with high thermal and air stabilities is presented as a homogenous catalyst for cycloisomerization of alkynyl amines to indoles. The nanocluster, characterized as [Au25(iPr2-bimy)10Br7]2+ (iPr2-bimy=1,3-diisopropylbenzimidazolin-2-ylidene) (1), was synthesized by direct reduction of AuSMe2Cl and iPr2-bimyAuBr with NaBH4 in one pot. X-ray crystallization analysis …
Tertiary Chiral Nanostructures from C‐H∙∙∙F Directed Assembly of Chiroptical Superatoms
Chiral hierarchical structures are universal in nature, whereas quite challenging to mimic in man-made synthesis. We report herein the synthesis and structure of tertiary chiral nanostructures with 100% optical purity. A novel synthetic strategy, using chiral reducing agent, R and S -BINAPCuBH 4 (BINAP is 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl), is developed to access to atomically precise, intrinsically chiral [Au 7 Ag 6 Cu 2 ( R - or S -BINAP) 3 (SCH 2 Ph) 6 ]SbF 6 nanoclusters in one-pot synthesis. The clusters represent the first tri-metallic superatoms with inherent chirality and fair stability. Both metal distribution (primary) and ligand arrangement (secondary) of the enantiomer…
Surface Coordination of Multiple Ligands Endows N‐Heterocyclic Carbene‐Stabilized Gold Nanoclusters with High Robustness and Surface Reactivity
Deciphering the molecular pictures of the multi-component and non-periodic organic-inorganic interlayer is a grand technical challenge. Here we show that the atomic arrangement of hybrid surface ligands on metal nanoparticles can be precisely quantified through comprehensive characterization of a novel gold cluster, Au 44 ( i Pr 2 -bimy) 9 (PA) 6 Br 8 , which features three types of ligands, namely, carbene (1,3-diisopropylbenzimidazolin-2-ylidene, i Pr 2 -bimy), alkynyl (phenylacetylide, PA), and halide (Br), respectively. The delicately balanced stereochemical effects and bonding capabilities of the three ligands give rise to peculiar geometrical and electronic structures. Remarkably, des…
Solubility-Driven Isolation of a Metastable Nonagold Cluster with Body-Centered Cubic Structure.
The conventional synthetic methodology of atomically precise gold nanoclusters using reduction in solutions offers only thermodynamically most stable nanoclusters. We report herein a solubility‐driven isolation strategy to access the synthesis of a metastable gold cluster. The cluster, with the composition of [Au 9 (PPh 3 ) 8 ] + ( 1 ), displays an unusual, nearly perfect body‐centered‐cubic (bcc) structure. As revealed by ESI‐MS and UV/Vis measurement, the cluster is metastable in solution and converts to the well‐known [Au 11 (PPh 3 ) 8 Cl 2 ] + ( 2 ) within just 90 min. DFT calculations revealed that while both 1 and 2 are eight‐electron superatoms, there is a driving force to convert 1 …
Copper-hydride nanoclusters with enhanced stability by N-heterocyclic carbenes
AbstractCopper-hydrides have been intensively studied for a long time due to their utilization in a variety of technologically important chemical transformations. Nevertheless, poor stability of the species severely hinders its isolation, storage and operation, which is worse for nano-sized ones. We report here an unprecedented strategy to access to ultrastable copper-hydride nanoclusters (NCs), namely, using bidentate N-heterocyclic carbenes as stabilizing ligands in addition to thiolates. In this work, a simple synthetic protocol was developed to synthesize the first large copper-hydride nanoclusters (NCs) stabilized by N-heterocyclic carbenes (NHCs). The NC, with the formula of Cu31(RS)2…
Automatic Segmentation of Pulmonary Lobes in Pulmonary CT Images using Atlas-based Unsupervised Learning Network
Pulmonary lobes segmentation of pulmonary CT images is important for assistant therapy and diagnosis of pulmonary disease in many clinical tasks. Recently supervised deep learning methods are applied widely in fast automatic medical image segmentation including pulmonary lobes segmentation of pulmonary CT images. However, they require plenty of ground truth due to their supervised learning scheme, which are always difficult to realize in practice. To address this issue, in this study we extend an existed unsupervised learning network with an extra pulmonary mask constraint to develop a deformable pulmonary lobes atlas and apply it for fast automatic segmentation of pulmonary lobes in pulmon…
Oligodendrocytes Support Neuronal Glutamatergic Transmission via Expression of Glutamine Synthetase.
Summary: Glutamate has been implicated in a wide range of brain pathologies and is thought to be metabolized via the astrocyte-specific enzyme glutamine synthetase (GS). We show here that oligodendrocytes, the myelinating glia of the central nervous system, also express high levels of GS in caudal regions like the midbrain and the spinal cord. Selective removal of oligodendrocyte GS in mice led to reduced brain glutamate and glutamine levels and impaired glutamatergic synaptic transmission without disrupting myelination. Furthermore, animals lacking oligodendrocyte GS displayed deficits in cocaine-induced locomotor sensitization, a behavior that is dependent on glutamatergic signaling in th…
Highly Robust but Surface-Active: N-Heterocyclic Carbene-Stabilized Au25 Nanocluster as a Homogeneous Catalyst
<div> <div> <div> <p>Surface organic ligands play a critical role in stabilizing atomically precise metal nanoclusters in solutions. However, it is still challenging to prepare highly robust ligated metal nanoclusters that are surface-active for liquid-phase catalysis without any pre-treatment. Herein, we report a novel N-heterocyclic carbine-stabilized Au25 nanocluster with high thermal and air stabilities as a homogenous catalyst for cycloisomerization of alkynyl amines to indoles. The nanocluster, characterized as [Au25(iPr2-bimy)10Br7]2+ (iPr2-bimy=diisopropyl-benzilidazolium) (1), was synthesized by direct reduction of AuSMe2Cl and iPr2- bimyAuBr with NaBH4 in o…
Highly Robust but Surface‐Active: An N‐Heterocyclic Carbene‐Stabilized Au 25 Nanocluster
Surface organic ligands play a critical role in stabilizing atomically precise metal nanoclusters in solutions. However, it is still challenging to prepare highly robust ligated metal nanoclusters that are surface-active for liquid-phase catalysis without any pre-treatment. Now, an N-heterocyclic carbene-stabilized Au25 nanocluster with high thermal and air stabilities is presented as a homogenous catalyst for cycloisomerization of alkynyl amines to indoles. The nanocluster, characterized as [Au25 (i Pr2 -bimy)10 Br7 ]2+ (i Pr2 -bimy=1,3-diisopropylbenzimidazolin-2-ylidene) (1), was synthesized by direct reduction of AuSMe2 Cl and i Pr2 -bimyAuBr with NaBH4 in one pot. X-ray crystallization…
CCDC 2050535: Experimental Crystal Structure Determination
Related Article: Hui Shen, Lingzheng Wang, Omar López-Estrada, Chengyi Hu, Qingyuan Wu, Dongxu Cao, Sami Malola, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2021|Nano Res.|14|3303|doi:10.1007/s12274-021-3389-9
CCDC 2096619: Experimental Crystal Structure Determination
Related Article: Hui Shen, Zhen Xu, Lingzheng Wang, Ying-Zi Han, Xianhu Liu, Sami Malola, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2021|Angew.Chem.,Int.Ed.|60|22411|doi:10.1002/anie.202108141
CCDC 1998895: Experimental Crystal Structure Determination
Related Article: Hui Shen, Zhen Xu, Maryam Sabooni Asre Hazer, Qingyuan Wu, Jiang Peng, Ruixuan Qin, Sam Malola, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2020|Angew.Chem.,Int.Ed.|60|3752|doi:10.1002/anie.202013718
CCDC 2096621: Experimental Crystal Structure Determination
Related Article: Hui Shen, Zhen Xu, Lingzheng Wang, Ying-Zi Han, Xianhu Liu, Sami Malola, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2021|Angew.Chem.,Int.Ed.|60|22411|doi:10.1002/anie.202108141
CCDC 1967410: Experimental Crystal Structure Determination
Related Article: Hui Shen, Elli Selenius, Pengpeng Ruan, Xihua Li, Peng Yuan, Omar Lopez-Estrada, Sami Malola, Shuichao Lin, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2020|Chem.-Eur.J.|26|8465|doi:10.1002/chem.202001753
CCDC 1916156: Experimental Crystal Structure Determination
Related Article: Hui Shen, Guocheng Deng, Sami Kaappa, Tongde Tan, Ying-Zi Han, Sami Malola, Shui-Chao Lin, Boon K. Teo, Hannu Häkkinen, Nanfeng Zheng|2019|Angew.Chem.,Int.Ed.|58|17731|doi:10.1002/anie.201908983