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1.
Stable ‐ESiMe3 Complexes of CuI and AgI (E=S,Se) with NHCs: Synthons in Ternary Nanocluster Assembly 下载免费PDF全文
Mahmood Azizpoor Fard Tetyana I. Levchenko Carolyn Cadogan William J. Humenny Prof. Dr. John F. Corrigan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4543-4550
As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag?ESiMe3] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [(iPr2‐bimy)Cu?ESiMe3]2 (iPr2‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr‐bimy)CuOAc] respectively, and E(SiMe3)2 at low temperature. The reaction of [(IPr)Ag?ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag?S? fragments bonded to a central HgII, representing a mixed mercury–silver sulfide complex. The reaction of [(iPr2‐bimy)Cu‐SSiMe3]2, which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2‐bimy)6Cu10S8Hg3] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy (1H and 13C), elemental analysis and single‐crystal X‐ray diffraction. 相似文献
2.
Isolation and Total Structure Determination of an All‐Alkynyl‐Protected Gold Nanocluster Au144 下载免费PDF全文
Dr. Zhen Lei Jiao‐Jiao Li Dr. Xian‐Kai Wan Wen‐Han Zhang Prof. Dr. Quan‐Ming Wang 《Angewandte Chemie (International ed. in English)》2018,57(28):8639-8643
Total structure determination of a ligand‐protected gold nanocluster, Au144, has been successfully carried out. The composition of title nanocluster is Au144(C≡CAr)60 ( 1 ; Ar=2‐FC6H4‐). The cluster 1 exhibits a quasi‐spherical Russian doll‐like architecture, comprising a Au54 two‐shelled Mackay icosahedron (Au12@Au42), which is further enclosed by a Au60 anti‐Mackay icosahedral shell. The Au114 kernel is enwrapped by thirty linear ArC≡C‐Au‐C≡CAr staple motifs. The absorption spectrum of 1 shows two bands at 560 and 620 nm. This spectrum is distinctly different from that of thiolated Au144, which was predicted to have an almost identical metal kernel and very similar ligands arrangement in 1 . These facts indicate the molecule‐like behavior of 1 and significant involvement of ligands in the electronic structure of 1 . The cluster 1 is hitherto the largest coinage metal nanocluster with atomically precise molecular structure in the alkynyl family. The work not only addresses the concern of structural information of Au144, which had been long‐pursued, but also provides an interesting example showing ligand effects on the optical properties of ligand protected metal nanoclusters. 相似文献
3.
Dr. David Schmidt David Bialas Prof. Dr. Frank Würthner 《Angewandte Chemie (International ed. in English)》2015,54(12):3611-3614
The unexpected introduction of a cationic imidazolium substituent in the 2‐position of a tetrachloro‐substituted perylene‐3,4:9,10‐tetracarboxylic acid bisimide (PBI) by the reaction of PBI‐Cl4 1 with the N‐heterocyclic carbene 1,3‐di‐iso‐propyl‐imidazolin‐2‐ylidene (iPr2Im 2 ) enables the isolation of an ambient stable zwitterionic radical. The remarkable stability of this unprecedented PBI‐centered radical facilitates the complete characterization by several spectroscopic methods as well as single crystal structure analysis. Redox studies revealed that iPr2Im‐PBI‐Cl4 4 can be transferred reversibly to the corresponding anion and cation, respectively, even on a preparative scale. 相似文献
4.
Template Synthesis,Metalation, and Self‐Assembly of Protic Gold(I)/(NHC)2 Tectons Driven by Metallophilic Interactions 下载免费PDF全文
Prof. Javier Ruiz Dr. Lucía García Daniel Sol Dr. Marilín Vivanco 《Angewandte Chemie (International ed. in English)》2016,55(29):8386-8390
A new protocol for the synthesis of protic bis(N‐heterocyclic carbene) complexes of AuI by a stepwise metal‐controlled coupling of isocyanide and propargylamine is described. They are used as tectons for the construction of supramolecular architectures through metalation and self‐assembly. Notably a unique polymeric chain of CuI with alternate AuI/bis(imidazolate) bridging scaffolds and strong unsupported CuI–CuI interactions has been generated, as well as a 28‐metal‐atoms cluster containing a nanopiece of Cu2O trapped by peripheral AuI/bis(imidazolate) moieties. 相似文献
5.
Javier Ruiz Lucía García Daniel Sol Marilín Vivanco 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(29):8526-8530
A new protocol for the synthesis of protic bis(N‐heterocyclic carbene) complexes of AuI by a stepwise metal‐controlled coupling of isocyanide and propargylamine is described. They are used as tectons for the construction of supramolecular architectures through metalation and self‐assembly. Notably a unique polymeric chain of CuI with alternate AuI/bis(imidazolate) bridging scaffolds and strong unsupported CuI–CuI interactions has been generated, as well as a 28‐metal‐atoms cluster containing a nanopiece of Cu2O trapped by peripheral AuI/bis(imidazolate) moieties. 相似文献
6.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(45):14470-14474
Facile oxygenation of the acyclic amido‐chlorosilylene bis(N‐heterocyclic carbene) Ni0 complex [{N(Dipp)(SiMe3)ClSi:→Ni(NHC)2] ( 1 ; Dipp=2,6‐iPr2C6H4; N‐heterocyclic carbene=C[(iPr)NC(Me)]2) with N2O furnishes the first Si‐metalated iminosilane, [DippN=Si(OSiMe3)Ni(Cl)(NHC)2] ( 3 ), in a rearrangement cascade. Markedly, the formation of 3 proceeds via the silanone (Si=O)–Ni π‐complex 2 as the initial product, which was predicted by DFT calculations and observed spectroscopically. The Si=O and Si=N moieties in 2 and 3 , respectively, show remarkable hydroboration reactivity towards H−B bonds of boranes, in the former case corroborating the proposed formation of a (Si=O)–Ni π‐complex at low temperature. 相似文献
7.
Probing the Limits of Ligand Steric Bulk: Backbone CH Activation in a Saturated N‐Heterocyclic Carbene 下载免费PDF全文
Nicholas Phillips Remi Tirfoin Prof. Simon Aldridge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(13):3825-3830
The consequences of extremely high steric loading have been probed for late transition metal complexes featuring the expanded ring N‐heterocyclic carbene 6‐Dipp. The reluctance of this ligand to form 2:1 complexes with d‐block metals (rationalised on the basis of its percentage buried volume, % Vbur, of 50.8 %) leads to C?H and C?N bond activation processes driven by attack at the backbone β‐CH2 unit. In the presence of IrI (or indeed H+) the net result is the formation of an allyl formamidine fragment, while AuI brings about an additional ring (re‐)closure step via nucleophilic attack at the coordinated alkene. The net transformation of 6‐Dipp in the presence of [(6‐Dipp)Au]+ represents to our knowledge the first example of backbone C?H activation of a saturated N‐heterocyclic carbene, proceeding in this case via a mechanism which involves free carbene in addition to the AuI centre. 相似文献
8.
Jiao‐Jiao Li Zong‐Jie Guan Zhen Lei Feng Hu Quan‐Ming Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1095-1099
Two homoleptic alkynyl‐protected gold clusters with compositions of Na[Au25(C≡CAr)18] and (Ph4P)[Au25(C≡CAr)18] (Na? 1 and Ph4P? 1 , Ar=3,5‐bis(trifluoromethyl)phenyl) were synthesized via a direct reduction method. 1 is a magic cluster analogous to [Au25(SR)18]? in terms of electron counts and metal‐to‐ligand ratio. Single‐crystal structure analysis reveals that 1 has an identical Au13 kernel to [Au25(SR)18]?, but adopts a distinctly different arrangement of the six peripheral dimer staple motifs. The steric hindrance of alkynyl ligands is responsible for the D3 arrangement of Au25. The introduction of alkynyl also significantly changes the optical absorption features of the nanocluster as supported by DFT calculations. This magic cluster confirms that there is a similar but quite different parallel alkynyl‐protected metal cluster universe in comparison to the thiolated one. 相似文献
9.
Bimetallic Au2Cu6 Nanoclusters: Strong Luminescence Induced by the Aggregation of Copper(I) Complexes with Gold(0) Species 下载免费PDF全文
Xi Kang Shuxin Wang Yongbo Song Shan Jin Guodong Sun Prof. Haizhu Yu Prof. Manzhou Zhu 《Angewandte Chemie (International ed. in English)》2016,55(11):3611-3614
The concept of aggregation‐induced emission (AIE) has been exploited to render non‐luminescent CuISR complexes strongly luminescent. The CuISR complexes underwent controlled aggregation with Au0. Unlike previous AIE methods, our strategy does not require insoluble solutions or cations. X‐ray crystallography validated the structure of this highly fluorescent nanocluster: Six thiolated Cu atoms are aggregated by two Au atoms (Au2Cu6 nanoclusters). The quantum yield of this nanocluster is 11.7 %. DFT calculations imply that the fluorescence originates from ligand (aryl groups on the phosphine) to metal (CuI) charge transfer (LMCT). Furthermore, the aggregation is affected by the restriction of intramolecular rotation (RIR), and the high rigidity of the outer ligands enhances the fluorescence of the Au2Cu6 nanoclusters. This study thus presents a novel strategy for enhancing the luminescence of metal nanoclusters (by the aggregation of active metal complexes with inert metal atoms), and also provides fundamental insights into the controllable synthesis of highly luminescent metal nanoclusters. 相似文献
10.
Lingwen Liao Chengming Wang Shengli Zhuang Nan Yan Yan Zhao Ying Yang Jin Li Haiteng Deng Zhikun Wu 《Angewandte Chemie (International ed. in English)》2020,59(2):731-734
Kernel atoms of Au nanoclusters are packed layer‐by‐layer along the [001] direction with every full (001) monolayer composed of 8 Au atoms (Au8 unit) in nanoclusters with formula of Au8n+4(TBBT)4n+8 (n is the number of Au8 units; TBBTH=4‐tert‐butylbenzenelthiol). It is unclear whether the kernel atoms can be stacked in a defective‐layer way along the [001] direction during growth of the series of nanoclusters and how the kernel layer number affects properties. Now, a nanocluster is synthesized that is precisely characterized by mass spectrometry and single‐crystal X‐ray crystallography, revealing a layer stacking mode in which a half monolayer composed of 4 atoms (Au4 unit) is stacked on the full monolayer along the [001] direction. The size and the odevity of the kernel layer number influence the properties (polarity, photoluminescence) of gold nanoclusters. The obtained nanocluster extends the previous formula from Au8n+4(TBBT)4n+8 to Au4n+4(TBBT)2n+8 (n is the number of Au4 units). 相似文献
11.
A Bis(Diphosphanyl N‐Heterocyclic Carbene) Gold Complex: A Synthon for Luminescent Rigid AuAg2 Arrays and Au5 and Cu6 Double Arrays 下载免费PDF全文
Pengfei Ai Dr. Matteo Mauro Prof. Luisa De Cola Dr. Andreas A. Danopoulos Dr. Pierre Braunstein 《Angewandte Chemie (International ed. in English)》2016,55(10):3338-3341
A mononuclear bis(NHC)/AuI (NHC=N‐heterocyclic carbene) cationic complex with a rigid bis(phosphane)‐functionalized NHC ligand (PCNHCP) was used to construct linear Au3 and Ag2Au arrays, a Au5 cluster with two intersecting crosslike Au3 arrays, and an unprecedented Cu6 complex with two parallel Cu3 arrays. The impact of metallophilic interactions on photoluminescence was studied experimentally. 相似文献
12.
Ji-Qiang Fan Dr. Ying Yang Cheng-Bo Tao Prof. Man-Bo Li 《Angewandte Chemie (International ed. in English)》2023,62(6):e202215741
A gold nanocluster Au17Cd2(PNP)2(SR)12 (PNP=2,6-bis(diphenylphosphinomethyl)pyridine, SR=4-MeOPhS) consisting of an icosahedral Au13 kernel, two Au2CdS6 staple motifs, and two PNP pincer ligands has been designed, synthesized and well characterized. This cadmium and PNP pincer ligand co-modified gold nanocluster showed high catalytic efficiency in the KA2 reaction, featuring high TON, mild reaction conditions, broad substrate scope as well as catalyst recyclability. Comparison of the catalytic performance between Au17Cd2(PNP)2(SR)12 and the structurally similar single cadmium (or PNP) modified gold nanoclusters demonstrates that the co-existence of the cadmium and PNP on the surface is crucial for the high catalytic activity of the gold nanocluster. This work would be enlightening for developing efficient catalysts for cascade reactions and discovering the catalytic potential of metal nanoclusters in organic transformations. 相似文献
13.
S. M. Ibrahim Al‐Rafia Dr. Robert McDonald Dr. Michael J. Ferguson Prof. Dr. Eric Rivard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(43):13810-13820
Various low oxidation state (+2) group 14 element amidohydride adducts, IPr ? EH(BH3)NHDipp (E=Si or Ge; IPr=[(HCNDipp)2C:], Dipp=2,6‐iPr2C6H3), were synthesized. Thermolysis of the reported adducts was investigated as a potential route to Si‐ and Ge‐based clusters; however, unexpected transmetallation chemistry occurred to yield the carbene–borane adduct, IPr ? BH2NHDipp. When a solution of IPr ? BH2NHDipp in toluene was heated to 100 °C, a rare C? N bond‐activation/ring‐expansion reaction involving the bound N‐heterocyclic carbene donor (IPr) transpired. 相似文献
14.
A Facile Route to Backbone‐Tethered N‐Heterocyclic Carbene (NHC) Ligands via NHC to aNHC Rearrangement in NHC Silicon Halide Adducts 下载免费PDF全文
Heidi Schneider Dr. David Schmidt Prof. Dr. Udo Radius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2793-2797
The reaction of 1,3‐diisopropylimidazolin‐2‐ylidene (iPr2Im) with diphenyldichlorosilane (Ph2SiCl2) leads to the adduct (iPr2Im)SiCl2Ph2 1 . Prolonged heating of isolated 1 at 66 °C in THF affords the backbone‐tethered bis(imidazolium) salt [(aHiPr2Im)2SiPh2]2+ 2 Cl? 2 (“a” denotes “abnormal” coordination of the NHC), which can be synthesized in high yields in one step starting from two equivalents of iPr2Im and Ph2SiCl2. Imidazolium salt 2 can be deprotonated in THF at room temperature using sodium hydride as a base and catalytic amounts of sodium tert‐butoxide to give the stable N‐heterocyclic dicarbene (aiPr2Im)2SiPh2 3 , in which two NHCs are backbone‐tethered with a SiPh2 group. This easy‐to‐synthesize dicarbene 3 can be used as a novel ligand type in transition metal chemistry for the preparation of dinuclear NHC complexes, as exemplified by the synthesis of the homodinuclear copper(I) complex [{a(ClCu?iPr2Im)}2SiPh2] 4 . 相似文献
15.
Yanwei Cao Jian‐Gong Yang Yi Deng Shengchun Wang Qi Liu Chaoren Shen Wei Lu Chi‐Ming Che Yong Chen Lin He 《Angewandte Chemie (International ed. in English)》2020,59(5):2080-2084
A sensitive amine‐responsive disassembly of self‐assembled AuI‐CuI double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)2][CuI2] revealed the contribution of Cu‐assisted ligand exchange of N‐heterocyclic carbene (NHC) by amine in [Au(NHC)2]+ and the capacity of [CuI2]? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d10 metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates. 相似文献
16.
Zong‐Jie Guan Jiu‐Lian Zeng Shang‐Fu Yuan Feng Hu Dr. Yu‐Mei Lin Prof. Quan‐Ming Wang 《Angewandte Chemie (International ed. in English)》2018,57(20):5703-5707
The controlled synthesis and structure determination of a bimetallic nanocluster Au57Ag53(C≡CPh)40Br12 (Au57Ag53) is presented. The metal core has a four‐shell Au2M3@Au34@Ag51 @Au20 (M=1/3 Au+2/3 Ag) architecture. In contrast to the previously reported large nanoclusters that have highly symmetric kernel structures, the metal atoms in Au57Ag53 are arranged in an irregular manner with C1 symmetry. This cluster exhibits excellent thermal stability and is robust under oxidative or basic conditions. The silver precursors play a key role in dictating the structures of the nanoclusters, which suggests the importance of the counteranions used. 相似文献
17.
Chuanhao Yao Cong‐Qiao Xu In‐Hyeok Park Meng Zhao Ziyu Zhu Jing Li Xiao Hai Hanyan Fang Yong Zhang Gennevieve Macam Jinghua Teng Lin Li Qing‐Hua Xu Feng‐Chuan Chuang Junpeng Lu Chenliang Su Jun Li Jiong Lu 《Angewandte Chemie (International ed. in English)》2020,59(21):8270-8276
Ligand‐induced surface restructuring with heteroatomic doping is used to precisely modify the surface of a prototypical [Au25(SR1)18]? cluster ( 1 ) while maintaining its icosahedral Au13 core for the synthesis of a new bimetallic [Au19Cd3(SR2)18]? cluster ( 2 ). Single‐crystal X‐ray diffraction studies reveal that six bidentate Au2(SR1)3 motifs (L2) attached to the Au13 core of 1 were replaced by three quadridentate Au2Cd(SR2)6 motifs (L4) to create a bimetallic cluster 2 . Experimental and theoretical results demonstrate a stronger electronic interaction between the surface motifs (Au2Cd(SR2)6) and the Au13 core, attributed to a more compact cluster structure and a larger energy gap of 2 compared to that of 1 . These factors dramatically enhance the photoluminescence quantum efficiency and lifetime of crystal of the cluster 2 . This work provides a new route for the design of a wide range of bimetallic/alloy metal nanoclusters with superior optoelectronic properties and functionality. 相似文献
18.
Metal‐Free Dihydrogen Oxidation by a Borenium Cation: A Combined Electrochemical/Frustrated Lewis Pair Approach 下载免费PDF全文
Elliot J. Lawrence Thomas J. Herrington Dr. Andrew E. Ashley Dr. Gregory G. Wildgoose 《Angewandte Chemie (International ed. in English)》2014,53(37):9922-9925
In order to use H2 as a clean source of electricity, prohibitively rare and expensive precious metal electrocatalysts, such as Pt, are often used to overcome the large oxidative voltage required to convert H2 into 2 H+ and 2 e?. Herein, we report a metal‐free approach to catalyze the oxidation of H2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H2 with the in situ electrochemical oxidation of the resulting borohydride. The use of the NHC‐stabilized borenium cation [(IiPr2)(BC8H14)]+ (IiPr2=C3H2(NiPr)2, NHC=N‐heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol?1. The NHC–borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C6F5)3, the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach. 相似文献
19.
Dr. Jing Liu Dr. Katla Sai Krishna Dr. Yaroslav B. Losovyj Dr. Soma Chattopadhyay Dr. Natalia Lozova Prof. Jeffrey T. Miller Prof. James J. Spivey Dr. Challa S. S. R. Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(31):10201-10208
We present results from our investigations into correlating the styrene‐oxidation catalysis of atomically precise mixed‐ligand biicosahedral‐structure [Au25(PPh3)10(SC12H25)5Cl2]2+ (Au25‐bi) and thiol‐stabilized icosahedral core–shell‐structure [Au25(SCH2CH2Ph)18]? (Au25‐i) clusters with their electronic and atomic structure by using a combination of synchrotron radiation‐based X‐ray absorption fine‐structure spectroscopy (XAFS) and ultraviolet photoemission spectroscopy (UPS). Compared to bulk Au, XAFS revealed low Au–Au coordination, Au? Au bond contraction and higher d‐band vacancies in both the ligand‐stabilized Au clusters. The ligands were found not only to act as colloidal stabilizers, but also as d‐band electron acceptor for Au atoms. Au25‐bi clusters have a higher first‐shell Au coordination number than Au25‐i, whereas Au25‐bi and Au25‐i clusters have the same number of Au atoms. The UPS revealed a trend of narrower d‐band width, with apparent d‐band spin–orbit splitting and higher binding energy of d‐band center position for Au25‐bi and Au25‐i. We propose that the differences in their d‐band unoccupied state population are likely to be responsible for differences in their catalytic activity and selectivity. The findings reported herein help to understand the catalysis of atomically precise ligand‐stabilized metal clusters by correlating their atomic or electronic properties with catalytic activity. 相似文献
20.
Federica Guarra Alessio Terenzi Christine Pirker Rossana Passannante Dina Baier Ennio Zangrando Vanessa Gmez‐Vallejo Tarita Biver Chiara Gabbiani Walter Berger Jordi Llop Luca Salassa 《Angewandte Chemie (International ed. in English)》2020,59(39):17130-17136
AuIII complexes with N‐heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII‐NHC complexes by direct oxidation with radioactive [124I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII‐to‐AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII‐NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation. 相似文献