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Zum Golde drängt, am
Golde hängt doch alles.
For gold contend, On gold depend All
things.
J. W. Goethe, Faust I
The element gold has many personalities, of which the image of a noble but soft, yellow metal would first across one's mind. The recently discovered nanoparticles and nanowires containing gold are a natural extension of this aspect, as are the uses of gold in electronics and decoration. Thought to be noble, gold actually has a rich chemistry. Fascinating in its complexity for academic chemists, this chemistry has potential applications in materials science, medicine and, recently, in both heterogeneous and homogeneous catalysis. Some fresh promises are related to the optical properties of certain gold compounds or to the possibility of forming new nanostructures based on gold. The unique properties of gold are strongly influenced by relativistic effects.
[1] P. Pyykkö, Theoretical Chemistry of
Gold
Angew. Chem. 2004, 116,
4512–4557; Angew. Chem. Int. Ed. 2004, 43,
4412–4456
[2] A. S. K. Hashmi, The Catalysis Gold Rush:
New
Claims
Angew. Chem. 2005, 117,
7150; Angew. Chem. Int. Ed. 2005, 44,
6990
[3] G. Schmid, B. Corain, Nanoparticulated Gold: Syntheses,
Structures, Electronics, and
Reactivities
Eur. J. Inorg. Chem. 2003,
3081
Find all articles on gold in Wiley Online Library...
Rafael Contreras-Cáceres, Isabel Pastoriza-Santos, Ramón A. Alvarez-Puebla, Jorge Pérez-Juste, Antonio Fernández-Barbero, Luis M. Liz-Marzán
Growing Au/Ag Nanoparticles within Microgel Colloids for Improved Surface-Enhanced Raman Scattering Detection [Communication]
Microgel grow-bags: Surface-enhanced Raman scattering (SERS)-active bimetallic core–shell spheres can be grown inside poly(N-isopropylacrylamide) (pNIPAM) microgels (see figure).
Roberto Sanz, Delia Miguel, Mukut Gohain, Patricia García-García, Manuel A. Fernández-Rodríguez, Adán González-Pérez, Olalla Nieto-Faza, Angel R. de Lera, Félix Rodríguez
Synthesis of Diverse Indole-Containing Scaffolds by Gold(I)-Catalyzed Tandem Reactions of 3-Propargylindoles Initiated by 1,2-Indole Migrations: Scope and Computational Studies [Full Paper]
Precious-metal catalysis: 3-Propargylindoles are able to participate in 1,2-migrations under gold-catalysis. 3-(Inden-2-yl)indoles could be accessed through gold-iso-Nazarov or gold-Nazarov cyclizations, whereas 3-(1,3-dien-2-yl)indoles are generated when none of these pathways are accessible.
Alexander Schätz, Oliver Reiser, Wendelin J. Stark
Nanoparticles as Semi-Heterogeneous Catalyst Supports [Review]
High surface area, excellent accessibility, and the ability to readily disperse in common solvents facilitate the use of nanoparticles as semi-heterogeneous supports. Reversible agglomeration through solvent changes and magnetic separation provide technically attractive alternatives to classical catalyst filtration.
A. Stephen K. Hashmi, Miriam Bührle, Michael Wölfle, Matthias Rudolph, Marcel Wieteck, Frank Rominger, Wolfgang Frey
Gold Catalysis: Tandem Reactions of Diyne–Diols and External Nucleophiles as an Easy Access to Tricyclic Cage-Like Structures [Full Paper]
Gold closes the cage: Diyne–diols and external nucleophiles in gold-catalysed reactions deliver rigid tricyclic heterocyclic compounds in high selectivity by a domino reaction. Eight new bonds are formed by hydroalkoxylation/hydrohydroxylation or hydroamination in good overall yields (see scheme).
Rongqing Li, Shuhong Xu, Chunlei Wang, Haibao Shao, Qinying Xu, Yiping Cui
Metal-Enhanced Fluorescence of CdTe Nanocrystals in Aqueous Solution [Article]
Metal-enhanced fluorescence: The Au-induced increased photoluminescence signal and decreased lifetimes of CdTe NCs are obtained through a very simple operation process. The concentration and the molar feed ratio of CdTe and Au nanoparticles related to the magnitude of enhanced photoluminescence are studied (see figure).
Benito Alcaide, Pedro Almendros, Teresa Martínez del Campo, Rocío Carrascosa
Metal-Catalyzed Cycloisomerization and Tandem Oxycyclization/Hydroxylation of Alkynols: Synthesis of Nonfused, Spiranic and Fused Oxabicyclic β-Lactams [Full Paper]
A variety of diversely functionalized nonfused, spiranic and fused oxabicyclic β-lactams can be prepared in good yield through precious metal catalyzed cycloisomerization and tandem oxycyclization/hydroxylation of alkynols. Silver exclusively affords cycloisomerization products, whereas the presence of a catalytic amount of platinum or gold salts favors the formation of tandem oxycyclization/hydroxylation adducts.
Eur. J. Org. Chem., July 13, 2010, DOI: 10.1002/ejoc.201000710
Yong Liu, Chun-Jiang Jia, Jun Yamasaki, Osamu Terasaki, Ferdi Schüth
Highly Active Iron Oxide Supported Gold Catalysts for CO Oxidation: How Small Must the Gold Nanoparticles Be? [Communication]
The shape of gold: The title catalyst has been prepared through a colloidal deposition method. Scanning transmission electron microscopy studies confirmed that for the catalyst, gold clusters with a bilayer structure and a diameter of about 0.5 nm are not mandatory to achieve the high activity (see image).
Angew. Chem. Int. Ed., July 12, 2010, DOI: 10.1002/anie.201000452
Di Wang, Alberto Villa, Paolo Spontoni, Dang Sheng Su, Laura Prati
In Situ Formation of Au–Pd Bimetallic Active Sites Promoting the Physically Mixed Monometallic Catalysts in the Liquid-Phase Oxidation of Alcohols [Full Paper]
Active alloys: Starting from a physical mixture of Au/AC and Pd/AC catalysts (AC=activated carbon), an Au–Pd alloy can be formed during the liquid-phase oxidation of alcohols by reprecipitation of Pd onto Au nanoparticles (see images). The alloy formation greatly enhances the catalyst activity.
Isabel Pastoriza-Santos, Ramón A. Alvarez-Puebla, Luis M. Liz-Marzán
Synthetic Routes and Plasmonic Properties of Noble Metal Nanoplates [Microreview]
Noble metal nanoplates display extremely interesting optical properties based on their characteristic plasmonic response. Thanks to the huge development of synthetic methods, both dimensions and surface plasmon resonances can be tuned in the visible and NIR, with many potential applications.
Eur. J. Inorg. Chem., July 9, 2010, DOI: 10.1002/ejic.201000575
David Monge, Kim L. Jensen, Patrick T. Franke, Lennart Lykke, Karl Anker Jørgensen
Asymmetric One-Pot Sequential Organo- and Gold Catalysis for the Enantioselective Synthesis of Dihydropyrrole Derivatives [Full Paper]
A golden combination: A direct asymmetric one-pot synthesis of optically active 2,3-dihydropyrroles from simple precursors is presented. The approach is based on a bifunctional organocatalytic Mannich-type reaction followed by AuI-catalyzed alkyne hydroamination (see scheme; TFA=trifluoroacetic acid). To highlight the synthetic potential of the accessed heterocyclic compounds, their transformation into 1-pyrrolines is presented.
Xiaoming He, Fernando Herranz, Eddie Chung-Chin Cheng, Ramon Vilar, Vivian Wing-Wah Yam
Design, Synthesis, Photophysics, and Anion-Binding Studies of Bis(dicyclohexylphosphino)methane-Containing Dinuclear Gold(I) Thiolate Complexes with Urea Receptors [Full Paper]
Anion-sensing Au complexes: Three different dinuclear gold(I) thiolate complexes incorporating a bis(dicyclohexylphosphino)methane ligand and urea receptor units have been synthesized. Differences between the luminescence properties seen in solution and the solid state are indicative of Au···Au interactions. By introducing electron-withdrawing NO2 groups to the system, a highly selective colorimetric probe, which shows a distinct color change from yellow to red in the presence of F− ions, was obtained (see graphic).
Christina Brandenberger, Christian Mühlfeld, Zulqurnain Ali, Anke-Gabriele Lenz, Otmar Schmid, Wolfgang J. Parak, Peter Gehr, Barbara Rothen-Rutishauser
Quantitative Evaluation of Cellular Uptake and Trafficking of Plain and Polyethylene Glycol-Coated Gold Nanoparticles [Full Paper]
The intracellular localization of gold nanoparticles (NPs), either plain or coated with polyethylene glycol (PEG), is quantitatively analyzed by stereology on transmission electron microscopy images. The NP surface coatings modulate endocytotic uptake pathways and intracellular trafficking. Nonendocytotic entry mechanisms are also involved, as indicated by a minority of PEG-coated NPs free within the cytosol.
William E. Brenzovich, Diego Benitez, Aaron D. Lackner, Hunter P. Shunatona, Ekaterina Tkatchouk, William A. Goddard, F. Dean Toste
Gold-Catalyzed Intramolecular Aminoarylation of Alkenes: C-C Bond Formation through Bimolecular Reductive Elimination [Communication]
Gold-ilocks and the 3 mol % catalyst: Bimetallic gold bromides allow the room temperature aminoarylation of unactivated terminal olefins with aryl boronic acids using Selectfluor as an oxidant. A catalytic cycle involving gold(I)/gold(III) and a bimolecular reductive elimination for the key C-C bond-forming step is proposed. dppm= bis(diphenylphosphanyl)methane.
Angew. Chem. Int. Ed., July 2, 2010, DOI: 10.1002/anie.201002739
Valeria La Parola, Alessandro Longo, Anna Maria Venezia, Alberto Spinella, Eugenio Caponetti
Interaction of Gold with Co-Condensed and Grafted HMS-SH Silica: A 29Si {1H} CP-MAS NMR Spectroscopy, XRD, XPS and Au LIII EXAFS Study [Full Paper]
The supporting capability of –SH modified HMS is evaluated by depositing gold through incipient wet impregnation. The effect of the two support functionalisation procedures, co-condensation and grafting,is investigated by XRD, Au LIII EXAFS and XPS. A stronger interaction between gold and the thiol groups is achieved in the grafted-SH silica with consequent better gold dispersion.
Eur. J. Inorg. Chem., July 1, 2010, DOI: 10.1002/ejic.201000427
George Z. Chen
A Golden Episode Continues Fenton’s Colorful Story [Highlight]
Stimulating new studies using Fenton’s reagent to selectively dissolve asperities and hence knock out catalytic sites on the surface of gold, may present unknown fundamental and applied opportunities; for example, modification of the surfaces of micro- and nanoparticles of gold and other metals to enhance catalytic activity, thereby making the process more affordable (see figure).
Angew. Chem. Int. Ed., June 29, 2010, DOI: 10.1002/anie.201001449
David Aguilar, Maria Contel, Esteban P. Urriolabeitia
Mechanistic Insights into the One-Pot Synthesis of Propargylamines from Terminal Alkynes and Amines in Chlorinated Solvents Catalyzed by Gold Compounds and Nanoparticles [Full Paper]
Golden reactions: Propargylamines can be obtained from amines and terminal alkynes in chlorinated solvents by catalysis with gold compounds and nanoparticles under mild reaction conditions (see scheme). The use of dichloromethane allows for the activation of two C-Cl bonds and a clean transfer of the methylene fragment to the final product.
Yue Zhang, Fugang Xu, Yujing Sun, Cunlan Guo, Kang Cui, Yan Shi, Zhiwei Wen, Zhuang Li
Seed-Mediated Synthesis of Au Nanocages and Their Electrocatalytic Activity towards Glucose Oxidation [Full Paper]
Au nanocages: For the first time, uniform Au nanocages with an outer-edge length of (54.6±13.3) nm were synthesized by a modified seed-mediated growth approach without the use of solid templates (see figure). The functions of the reagents were investigated in detail, and a possible mechanism for the growth of the nanocages was proposed.
Zhou Zhang, Lai Mun Wong, Hou Xiao Wang, Zhi Peng Wei, Wei Zhou, Shi Jie Wang, Tom Wu
Self-Assembled In-Plane Growth of Mg2SiO4 Nanowires on Si Substrates Catalyzed by Au Nanoparticles [Full Paper]
Self-assembled in-plane Mg2SiO4 nanowires are synthesized on Si substrates using Au nanoparticles as catalyst. Besides serving as the supporting substrates, Si actively takes part in the vapor–liquid–solid growth of the nanowires. The epitaxial growth also confines the nanowires along the Si <110> directions on Si (110), (100), and (111) substrates.
Adv. Funct. Mater., June 25, 2010, DOI: 10.1002/adfm.201000442
José María Cíes, Juan José Delgado, Miguel López-Haro, Ratchaneekorn Pilasombat, José Antonio Pérez-Omil, Susana Trasobares, Serafin Bernal, José Juan Calvino
Contributions of Electron Microscopy to Understanding CO Adsorption on Powder Au/Ceria–Zirconia Catalysts [Full Paper]
Model behaviour: A nanostructural model for the adsorption of CO on powder Au/ceria–zirconia catalysts, under conditions relevant to catalysis, is proposed by combining electron microscopy, computer modelling (see figure) and chemical analysis. This model highlights the key role of CO spillover in the adsorption on ceria–zirconia.
Alasdair W. Clark, Jonathan M. Cooper
Optical Properties of Multiple-Split Nanophotonic Ring Antennae [Communication]
Simulated plasmonic activity is reported for a series of Au nanoring antennae with 1–5 splits in their geometry. The rings have a radius of 75 nm and splits of 3–6 nm. By controlling the size of the splits, their location and the radius of the ring structure, we can control the number, intensity and frequency of the plasmonic hotspots.
Miguel Peña-López, Miguel Ayán-Varela, Luis A. Sarandeses, José Pérez Sestelo
Palladium-Catalyzed Cross-Coupling Reactions of Organogold(I) Reagents with Organic Electrophiles [Full Paper]
Gold C-C coupling: Organogold(I) reagents (aryl, alkenyl, alkynyl, alkyl) can be used in palladium-catalyzed cross-coupling reactions with different organic electrophiles, such as aryl and alkenyl halides, aryl triflates, benzyl bromide, and benzoyl chloride (see scheme; OTf=trifluoromethane sulfonate). The reaction generally proceeds at room temperature in high yields.
Xiu-Ling Li, Ke-Juan Zhang, Juan-Juan Li, Xin-Xin Cheng, Zhong-Ning Chen
Dual Luminescent Dinuclear Gold(I) Complexes of Terpyridyl-Functionalized Alkyne Ligands and Their Efficient Sensitization of EuIII and YbIII Luminescence [Full Paper]
The binuclear gold(I) complexes [(tpyC6H4C≡CAu)2{μ-Ph2P(CH2)nPPh2}] (n = 2–6) display dual luminescence at room temperature. Spectrophotometric titrationand quantum yields demonstrate that they can behave as good energy donors for EuIII and YbIII emission.
Eur. J. Inorg. Chem., June 16, 2010, DOI: 10.1002/ejic.201000324
Avelino Corma, Marta Iglesias, Francesc X. Llabrés i Xamena, Félix Sánchez
Cu and Au Metal–Organic Frameworks Bridge the Gap between Homogeneous and Heterogeneous Catalysts for Alkene Cyclopropanation Reactions [Full Paper]
Transfer of fragments: Metal–organic framework (MOF) materials containing either Cu or Au centers can act as catalysts (i.e., [Cu3(BTC)2] (BTC=benzene-1,3,5-tricarboxylate), and IRMOF-3-SI-Au) for the cyclopropanation of alkenes with diazoacetates (see scheme). This example is the first use of these materials to induce the carbene transfer reactions from diazo compounds.
Takato Mitsudome, Akifumi Noujima, Yusuke Mikami, Tomoo Mizugaki, Koichiro Jitsukawa, Kiyotomi Kaneda
Supported Gold and Silver Nanoparticles for Catalytic Deoxygenation of Epoxides into Alkenes [Communication]
Taking the 'O': Supported gold and silver nanoparticles (NPs), which are well-known epoxidation catalysts, were found to have intrinsic catalytic ability for the deoxygenation of epoxides into alkenes using alcohol as a reductant (see picture). The selectivity for all the alkenes were over 99 %, and an excellent turnover number was achieved. Furthermore, these supported gold and silver nanoparticles were recyclable.
Angew. Chem. Int. Ed., May 12, 2010, DOI: 10.1002/anie.201001055
Michele Melchionna, Martin Nieger, Juho Helaja
Isolation of a Zwitterionic Dienegold(III) Complex Intermediate in the Direct Conversion of Enyne–Amines to Cyclopentadienes [Communication]
Golden ring: A route for the direct AuCl3-catalyzed conversion of an enyne–amine into cyclopentadiene is reported. The mechanism for the catalysis is proposed and supported by a resting-state zwitterionic gold(III)-cyclopentadiene structure (see figure).
L.Y. Chen, T. Fujita, Y. Ding, M. W. Chen
A Three-Dimensional Gold-Decorated Nanoporous Copper Core–Shell Composite for Electrocatalysis and Nonenzymatic Biosensing [Full Paper]
A gold-decorated nanoporous copper core–shell composite is fabricated by a facile in situ hydrometallurgical approach. Gold shells are deposited onto the internal surfaces of 3D nanoporous copper via a spontaneous displacement reaction while copper is utilized as the reduction agent, 3D template, and substrate. The core–shell nanostructure exhibits significant electrocatalytic activity for the oxidation of methanol and high non-enzymatic sensitivity in detecting glucose.
Jun Zhang, Xianghong Liu, Xianzhi Guo, Shihua Wu, Shurong Wang
A General Approach to Fabricate Diverse Noble-Metal (Au, Pt, Ag, Pt/Au)/Fe2O3 Hybrid Nanomaterials [Full Paper]
Dual control! A novel, facile, and general one-pot strategy is explored for constructing diverse noble-metal (Au, Pt, Ag or Pt/Au)/Fe2O3 hybrid nanoparticles by using lysine as a dual linker and capping reagent (see figure). The hybrid Au/Fe2O3 nanoparticles exhibit significantly improved sensor performance in terms of high sensitivity, low detection limit, good selectivity, and reproducibility in comparison to pristine Fe2O3.
A. Stephen K. Hashmi
Homogeneous Gold Catalysis Beyond Assumptions and Proposals—Characterized Intermediates [Minireview]
Hard facts: Which intermediates of homogeneous gold-catalyzed conversions have been isolated or detected, and where do we enter the shaky grounds of speculation? The palette of proven intermediates extends from gold π complexes to pure organic cyclization products (see examples).
A. Stephen K. Hashmi, Christian Lothschütz, Martin Ackermann, René Doepp, Sankaran Anantharaman, Benjamin Marchetti, Helmut Bertagnolli, Frank Rominger
Gold Catalysis: In Situ EXAFS Study of Homogeneous Oxidative Esterification [Full Paper]
All that glitters! Investigations into gold-catalysed oxidative esterification with gold–pyridine complexes proves that the oxidation is truly homogeneous. The reaction flasks after the reaction has taken place under stabilised conditions (I–IV) and non-stabilised conditions (V–VII) are depicted.
Rongli Fan, Shu Wen Chew, Vee Vee Cheong, Brendan Patrick Orner
Fabrication of Gold Nanoparticles Inside Unmodified Horse Spleen Apoferritin [Communication]
Size-constrained gold nanoparticles are successfully synthesized within the cavity of native horse spleen ferritin by using a two-step process relying on the initial formation of nanoclusters. The particles co-elute with the nanocage ferritin by chromatography, indicating that the particles are associated with intact protein cages. Further characterization reveals that the growth of the monodisperse particles is limited by the protein cage.
Luca Beverina
Towards the Controlled Self-Assembly of Gold Nanoparticles [Highlight]
Control freaks: Recent developments in the design of neutral multidentate pyridine ligands enable the controlled cross-linking of gold nanoparticles in solution (see picture). Impressive results opening the way for a highly controlled self-assembly of intimate nanoparticles are highlighted herein.
Zhen Zhang, Min Shi
Gold(I)-Catalyzed Domino Reaction of Aziridinyl Alkynes [Communication]
Aziridinyl alkynes strike gold: A novel gold(I)-catalyzed domino transformation of aziridinyl alkynes with arenes to construct 1,2,3,4-tetrahydroisoquinoline and 3,4-dihydroisoquinoline structural motifs (see scheme), especially sterically congested syn-3,4-disubstituted 1,2,3,4-tetrahydroisoquinolines, is described. A plausible mechanism proceeding through a benzylic cation is given based upon deuterium-labeling and control experiments as well as the observed diastereoselectivities.
Wei Huang, Hirofumi Tanaka, Takuji Ogawa, Xiao-Zeng You
Properties of Thiol End-Capped and Iodine-Doped Sexithiophene Disulfide Semiconducting Polymers Bridging Nanogap Gold Electrodes [Communication]
Doped photoresponsive nanodevices. A thiol end-capped and iodine-doped sexithiophene disulfide polymer is used to bridge nanogap gold electrodes via an in-situ oxidation, doping, and self-assembly method. Temperature-dependent semiconducting and photoresponsive nanodevices are formed and Coulomb-blockade phenomena are observed in these organic molecule-based nanodevices.
Yihong Shen, Shenghong Zhang, Hongjia Li, Yuan Ren, Haichao Liu
Efficient Synthesis of Lactic Acid by Aerobic Oxidation of Glycerol on Au–Pt/TiO2 Catalysts [Communication]
Go for the burn! A one-pot approach to the efficient synthesis of lactic acid through the aerobic oxidation of glycerol in the presence of bases at an atmospheric pressure of O2 is reported, which combines two consecutive reactions, including oxidative dehydrogenation of glycerol to its dehydrogenated intermediates and their subsequent isomerization (see scheme).
Ashok Mohanty, Niti Garg, Rongchao Jin
A Universal Approach to the Synthesis of Noble Metal Nanodendrites and Their Catalytic Properties [Communication]
Flower power: A universal approach is presented for high-yield synthesis of Au, Pt, and Pd nanoflowers using the surfactant sodium N-(4-n-dodecyloxybenzoyl)-L-isoleucinate (SDBIL). The pH-dependent self-assembly using SDBIL is critical for nanoflower growth. The Pt and Pd nanoflowers show superior catalytic activity for Suzuki–Miyaura and Heck coupling reactions over spherical counterparts.
Avelino Corma, Violeta R. Ruiz, Antonio Leyva-Pérez, María J. Sabater
Regio- and Stereoselective Intermolecular Hydroalkoxylation of Alkynes Catalysed by Cationic Gold(I) Complexes [Full Paper]
Ying Jiang, Hong Zhao, Yuqing Lin, Ningning Zhu, Yurong Ma, Lanqun Mao
Colorimetric Detection of Glucose in Rat Brain Using Gold Nanoparticles [Communication]
A gold-based assay: By taking advantage of the unique optical properties of gold nanoparticles (AuNPs) and the cascade reactions of glucose, a simple but effective method has been successfully developed for the direct colorimetric visualization of glucose in the rat brain. GOD=glucose oxidase.
Michael Riskin, Ran Tel-Vered, Marco Frasconi, Nimrod Yavo, Itamar Willner
Stereoselective and Chiroselective Surface Plasmon Resonance (SPR) Analysis of Amino Acids by Molecularly Imprinted Au-Nanoparticle Composites [Full Paper]
Au-nanoparticle composites detect amino acids: Selective and chiroselective surface plasmon resonance (SPR) analysis of amino acids is accomplished with molecularly imprinted bis-aniline-crosslinked Au-nanoparticle composites electropolymerized on Au surfaces (see graphic).
José Barluenga, Jonás Calleja, Abraham Mendoza, Félix Rodríguez, Francisco J. Fañanás
Synthesis of Polycyclic Compounds by a Cascade Cycloisomerisation/Diels–Alder Reaction [Communication]
Running rings around gold: A new cascade reaction catalysed by AuCl3 that is based upon an initial cycloisomerisation reaction of enynol or enynamine derivatives, which form 1,3-butadiene derivatives, followed by a Diels–Alder cycloaddition reaction to give fused or spirocyclic compounds is reported (see scheme).
Nicola Salvi, Leonardo Belpassi, Francesco Tarantelli
On the Dewar–Chatt–Duncanson Model for Catalytic Gold(I) Complexes [Full Paper]
Coordination bonds defined! A charge–displacement analysis reveals the full picture of σ donation and π back-donation in catalytic gold(I)–alkyne complexes (see figure; nhc=2,3-dihydroimidazol-2-ylidene).
Alberto Martínez, Patricia García-García, Manuel A. Fernández-Rodríguez, Félix Rodríguez, Roberto Sanz
Gold(I)-Catalyzed Enantioselective Synthesis of Functionalized Indenes [Communication]
Can you dig it? An asymmetric synthesis of functionalized 1H-indenes from easily available ortho-(alkynyl)styrene derivatives under mild reaction conditions has been achieved. The reactions proceed through an unprecedented and selective 5-endo-dig gold(I)-catalyzed cycloisomerization or alkoxycyclization, if water or an alcohol is present (see scheme).
Ling Lin, Pieterjan Claes, Philipp Gruene, Gerard Meijer, André Fielicke, Minh Tho Nguyen, Peter Lievens
Far-Infrared Spectra of Yttrium-Doped Gold Clusters AunY (n=1–9) [Article]
Gold digger: The vibrational spectra of AunY (n=4–9) clusters are recorded by photodissociation techniques and assigned with the aid of density functional calculations. Most of the isomers for which the IR spectra agree best with experiment are the calculated energetically most stable ones (see picture). All the AunY clusters considered prefer a low spin state, and the Y atom consistently adopts high coordination.
Prasath Kothandaraman, Weidong Rao, Shi Jia Foo, Philip Wai Hong Chan
Gold-Catalyzed Cycloisomerization Reactions of 2-Tosylaminophenylprop-1-yn-3-ols as a Versatile Approach for Indole Synthesis [Communication]
A great combination: A putative indolyl-substituted vinyl gold species generated in situ from AuCl/AgOTf catalyzed the title transformation. Under these reaction conditions, indenyl-fused and 2,3-disubstituted indole derivatives were produced in good to excellent yields of up to 94 % (see scheme).
Yunxia Hu, Dian Chen, Soojin Park, Todd Emrick, Thomas P. Russell
Guided Assemblies of Ferritin Nanocages: Highly Ordered Arrays of Monodisperse Nanoscopic Elements [Communication]
High-density arrays of highly ordered ferritin nanocages are fabricated through the guided assembly of thiol-modified ferritin on prepatterned gold nanodots, which are prepared by block copolymer micelle lithography. One and only one ferritin nanocage is anchored to each gold nanodot, as confirmed by scanning electron and scanning force microscopy.
Alberto Villa, Gabriel M. Veith, Laura Prati
Selective Oxidation of Glycerol under Acidic Conditions Using Gold Catalysts [Communication]
Skip the bases! H-mordenite-supported PtAu nanoparticles are highly active and selective in the oxidation of glycerol under acidic conditions, which allows the direct preparation of free acids (see picture). The high selectivity for C3 compounds results from the negligible formation of H2O2, in contrast to PtAu nanoparticles supported on activated carbon.
Hendrik O. Lintang, Kazushi Kinbara, Kenichi Tanaka, Takashi Yamashita, Takuzo Aida
Self-Repair of a One-Dimensional Molecular Assembly in Mesoporous Silica by a Nanoscopic Template Effect [Communication]
Upon confinement of a trinuclear gold(I) pyrazolate complex in a hexagonal silicate channel, the luminescence center formed by a AuI–AuI metallophilic interaction is not only protected against thermal disruption but also strongly encouraged to self-recover from a heat-induced structural damage. This nanoscopic template effect is negligible for a lamellar silica framework.
Hiroyuki Kusama, Yusuke Karibe, Yuji Onizawa, Nobuharu Iwasawa
Gold-Catalyzed Tandem Cyclization of Dienol Silyl Ethers for the Preparation of Bicyclo[4.3.0]nonane Derivatives [Communication]
Tandem bicycle: A gold-catalyzed geminal carbo-functionalization reaction of 3-siloxy-1,3-dien-8-ynes proceeded smoothly to give bicyclo[4.3.0]nonanes stereoselectively through ring expansion of the bicyclic carbene complex intermediates. The product configuration was different from that of the thermal Diels–Alder adduct.
Yukatsu Shichibu, Katsuaki Konishi
HCl-Induced Nuclearity Convergence in Diphosphine-Protected Ultrasmall Gold Clusters: A Novel Synthetic Route to “Magic-Number” Au13 Clusters [Communication]
A magic-number Au13 cluster with icosahedral geometry can be exclusively generated from a polydisperse mixture of ultrasmall 1,2-bis(diphenylphosphino)ethane-coordinated gold clusters upon treatment with HCl, which acts as an efficient promoter.
Dominic Thibeault, Michèle Auger, Jean-François Morin
Synthesis of Fluorine-Containing Molecular Rotors and Their Assembly on Gold Nanoparticles [Full Paper]
Molecular rotors with thiol anchors and bulky trityl headgroups were synthesized and assembled on gold nanoparticles. The rotating part of the rotor (rotator) is a phenyl group with alkyne substituents in the 1-and 4-positions, providing a low rotation energy barrier. Fluorine atoms were introduced onto the rotator allowing rotation dynamics inside monolayers to be studied by solid-state 19F NMR.
A. Stephen K. Hashmi, Tobias Hengst, Christian Lothschütz, Frank Rominger
New and Easily Accessible Nitrogen Acyclic Gold(I) Carbenes: Structure and Application in the Gold-Catalyzed Phenol Synthesis as well as the Hydration of Alkynes [Full Paper]
A. Stephen K. Hashmi, René Döpp, Christian Lothschütz, Matthias Rudolph, Dominic Riedel, Frank Rominger
Scope and Limitations of Palladium-Catalyzed Cross-Coupling Reactions with Organogold Compounds [Full Paper]
Benito Alcaide, Pedro Almendros, Rocío Carrascosa, M. Rosario Torres
Gold/Acid-Cocatalyzed Regiodivergent Preparation of Bridged Ketals via Direct Bis-Oxycyclization of Alkynic Acetonides [Communication]
Yong Wang, Changcheng He, Weihong Xing, Fengbin Li, Ling Tong, Zhiquan Chen, Xingzhi Liao, Martin Steinhart
Nanoporous Metal Membranes with Bicontinuous Morphology from Recyclable Block-Copolymer Templates [Communication]
Nondestructive preparation of bicontinuous nanoporous metal membranes by replication of bicontinuous nanoporous polymeric membranes consisting of recoverable asymmetric block copolymers (BCPs) is reported. The BCP membranes are generated by swelling the minority domains of the BCP with selective solvents accompanied by reconstruction of the glassy matrix formed by the majority component (see figure).
David A. Giljohann, Dwight S. Seferos, Weston L. Daniel, Matthew D. Massich, Pinal C. Patel, Chad A. Mirkin
Gold Nanoparticles for Biology and Medicine [Review]
Sitting on a gold mine: Gold nanoparticles have been developed and studied as gene-regulating agents, drug carriers, photoresponsive therapeutics, and as imaging platforms (see the nanoflare, which allows detection of mRNA by fluorescence microscopy). These structures have new properties that are advantageous for biological applications. This Review highlights the synthesis of gold nanoparticles and their application from cell-based assays to therapeutic materials.
Rajpal Singh, Thathan Premkumar, Ji-Young Shin, Kurt E. Geckeler
Carbon Nanotube and Gold-Based Materials: A Symbiosis [Review]
The interaction between carbon materials and gold provides access to new hybrid materials with useful properties for various potential applications. Here we provide an overview of the recent progress in this area by exploring the various synthesis approaches and types of assemblies, and study the diverse applications of the resulting composites (see graphic).
A. Stephen K. Hashmi, Christoph Hubbert
Gold and Organocatalysis Combined [Highlight]
All that glitters: Binary catalytic systems of gold(I) complexes and chiral Brønsted acids, which were recently reported by the research groups of Dixon and Gong, represent a significant leap forwards in the area of sequential one-pot reactions. The special feature of these reactions is the isolobal analogy of the proton and [LAuI] cations, which requires a delicate balance between the reactivities of the acids and the gold complexes.
Sung-Jin Kim, Gordon J. Miller, John D. Corbett
Zigzag Chains of Alternating Atoms in A2AuBi (A = Na, K) and K2AuSb. Synthesis, Structure, and Bonding [Contributions Dedicated to Professor Arndt Simon on the Occasion of His 70th Birthday]
Philippe Belmont, Evelyne Parker
Silver and Gold Catalysis for Cycloisomerization Reactions [Microreview]
In a “golden world”, silver-based opportunities for cycloisomerization reactions are also outlined. We offer a quick overview of the usefulness of each metal along with counterion effects. The need of some gold catalysts for activation through silver anion metathesis is also discussed, because it links two coinage metals of increasing interest in the field of organometallic chemistry.
Panikkanvalappil R. Sajanlal, Thalappil Pradeep
Reply to “Comments on Electric-Field-Assisted Growth of Highly Uniform and Oriented Gold Nanotriangles on Conducting Glass Substrates” [Comment]
Peng Diao, Dafeng Zhang, Min Guo, Qi Zhang
Comments on ‘Electric-Field-Assisted Growth of Highly Uniform and Oriented Gold Nanotriangles on Conducting Glass Substrates’ [Comment]
AFM artifacts: Recent results by Sajanlal and Pradeep on the electric-field-assisted growth of highly uniform and oriented gold nanotriangles appear to provide a simple route to the size-, shape-, and orientation-controlled synthesis of nano structures. In our view, however, the triangle patterns observed in the AFM images are not real surface features but artifacts produced by a broken or contaminated AFM tip.
Alan L. Balch
Dynamic Crystals: Visually Detected Mechanochemical Changes in the Luminescence of Gold and Other Transition-Metal Complexes [Highlight]
Back to the grindstone: Certain crystalline complexes of gold, platinum, and vanadium undergo dramatic changes in their luminescence or their color upon grinding. The picture shows the transformation of colorless crystals of [(F5C6Au)2(μ-1,4-CN2C6H4)] powder from a blue-emitting form (λmax=415 nm) to a yellow/green-emitting form (λmax=533 nm) on grinding with a pestle. The process is reversible.
Jill E. Millstone, Sarah J. Hurst, Gabriella S. Métraux, Joshua I. Cutler, Chad A. Mirkin
Colloidal Gold and Silver Triangular Nanoprisms [Review]
Nanoprisms, such as the Au prisms in the image (scale bar: 83 nm), exhibit unique chemical and optical features, promising for applications ranging from catalysis to therapeutics. This Review focuses on the wide variety of synthetic methods for preparing nanoprism structures and not only highlights some of the most effective approaches but also examines what these methods have uncovered about the underlying principles of colloidal anisotropic nanoparticle growth.
Cyrille Gautier, Thomas Bürgi
Chiral Gold Nanoparticles [Minireview]
Nanoparticle chirality has attracted much attention recently, and the application of chiral nanoparticles to chiral technologies (see figure) is also of interest. This Minireview deals with advances in the preparation and characterization of chiral gold nanoparticles. Origins of the chiroptical properties and potential applications are discussed.
© Wiley-VCH 2010.
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