This Account reports the synthesis and characterization of dendrimer-encapsulated metal nanoparticles their applications to catalysis. These materials are prepared by sequestering ions within dendrimers followed chemical reduction yield corresponding zerovalent nanoparticle. The size such particles depends on number initially loaded into dendrimer. Intradendrimer hydrogenation carbon-carbon coupling reactions in water, organic solvents, biphasic fluorous/organic supercritical CO2 also described.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPreparation of Cu Nanoclusters within Dendrimer TemplatesMingqi Zhao, Li Sun, and Richard M. CrooksView Author Information Department Chemistry, P.O. Box 300012 Texas A&M University, College Station, 77842-3012 Cite this: J. Am. Chem. Soc. 1998, 120, 19, 4877–4878Publication Date (Web):April 29, 1998Publication History Received9 February 1998Published online29 April inissue 1 May...

In this article we describe the synthesis, characterization, and applications of dendrimer-encapsulated nanoparticles (DENs). These materials are synthesized by a template approach in which metal ions extracted into interior dendrimers then subsequently chemically reduced to yield nearly size-monodisperse particles having dimensions less than 3 nm. Monometallic, bimetallic (including core/shell), semiconductor have been prepared route. The dendrimer component these composites serves not only...

Extraordinarily stable, monodisperse noble metal nanoparticles can be prepared by using dendrimers as both templates and stabilizers. Dendrimer-encapsulated Pd (see the schematic representation) exhibit high catalytic activity for hydrogenation of alkenes in water. The selectivity these materials controlled adjusting dendrimer generation.

We report a method, based on the principles of origami (paper folding), for fabricating three-dimensional (3-D) paper microfluidic devices. The entire 3-D device is fabricated single sheet flat in photolithographic step. It assembled by simply folding hand. Following analysis, can be unfolded to reveal each layer. applicability chemical analysis demonstrated colorimetric and fluorescence assays using multilayer networks.

Communication: Dendrimers act as templates for platinum nanoparticles. The authors describe a general synthetic approach whereby dendrimer nanotemplate is loaded with Pt2+, which reduced in situ to yield dendrimer-encapsulated metal cluster. clusters are monodisperse and very stable, when attached an electrode surface, they efficient electrocatalysts O2 reduction (see Figure).

We report a particle size dependence for the rate of hydrogenation allyl alcohol using 1.3−1.9 nm Pd dendrimer-encapsulated nanoparticle (DEN) catalysts. For particles with diameters <1.5 and containing <147 atoms, modulation in catalytic activity is due to electronic properties particle. larger particles, 1.5−1.9 diameter an average 147−250 effect result geometrical constraints. Specifically, reaction shown occur preferentially on face atoms nanoparticles.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPotential dependence of the conductivity highly oxidized polythiophenes, polypyrroles, and polyaniline: finite windows high conductivityDavid Ofer, Richard M. Crooks, Mark S. WrightonCite this: J. Am. Chem. Soc. 1990, 112, 22, 7869–7879Publication Date (Print):October 1, 1990Publication History Published online1 May 2002Published inissue 1 October 1990https://pubs.acs.org/doi/10.1021/ja00178a004https://doi.org/10.1021/ja00178a004research-articleACS...

Over the past decade, bipolar electrochemistry has emerged from relative obscurity to provide a promising new means for integrating into lab-on-a-chip systems. This article describes fundamental operating principles of electrodes, as well several interesting applications.

In this article we describe the synthesis, characterization, and applications of dendrimer-encapsulated nanoparticles (DENs). These materials are synthesized using a template approach in which metal ions extracted into interior dendrimers then subsequently reduced chemically to yield nearly size-monodisperse particles having diameters 1–2 nm range. Monometallic, bimetallic (alloy core@shell), semiconductor have been prepared by route. The dendrimer component these composites serves not only...

Paper biosensors: An origami sensor is printed on a single piece of paper, folded into three-dimensional fluidic device, and encapsulated by thermal lamination. Aptamer trapped in the channel, where it binds to target releases an enzyme generate signal. The device read out using digital multimeter.

We report a battery-powered, microelectrochemical sensing platform that reports its output using an electrochromic display. The is fabricated based on paper fluidics and uses Prussian blue spot electrodeposited indium-doped tin oxide thin film as the indicator. integrated metal/air battery powers both electrochemical sensor read-out, which are in electrical contact via reservoir. sample activates presence of analyte initiates color change spot. entire system assembled lab bench, without need...

Nearly monodisperse (1.7 ± 0.2 nm) palladium nanoparticles were prepared within the interiors of three different generations hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers. These dendrimer-encapsulated catalysts (DECs) used to hydrogenate allyl alcohol and four α-substituted derivatives in a 4:1 methanol/water mixture. The results indicate that steric crowding on dendrimer periphery, which increases with generation, can act as an adjustable-mesh nanofilter. That is, by controlling...

Highly monodisperse, 1−2-nm diameter Au nanoparticles were prepared using poly(amidoamine) (PAMAM) dendrimers as templates. The synthesis is carried out in water, takes less than 30 min, and requires no subsequent purification. having diameters of 1.3 ± 0.3 1.6 nm obtained when 55 140 equiv, respectively, HAuCl4 per dendrimer used. For unpurified this size range, represents more a 200% improvement distribution compared to previous reports. high monodispersity function the template synthesis,...

The synthesis, characterization, and catalytic properties of 1-3 nm-diameter bimetallic PdAu dendrimer-encapsulated catalysts are reported. Both alloy core/shell nanoparticles were prepared. hydrogenation allyl alcohol was significantly enhanced in the presence as compared to mixtures single-metal nanoparticles.

Palladium nanoparticles (2−3 nm in diameter) have been prepared within covalently functionalized poly(propylene imine) (PPI) dendrimers, and the resulting composite materials are shown to be effective for Heck coupling reactions. Two novel concepts demonstrated this report. The first concept involves incorporation of Pd0 into PPI dendrimers with perfluorinated polyether chains on their periphery. second example a carbon−carbon reaction catalyzed by dendrimer-templated nanomaterial,...

We report the synthesis, characterization, and catalytic activity of bimetallic palladium-platinum dendrimer-encapsulated catalysts (DECs). These materials are prepared by co-complexation different ratios palladium platinum salts to interior tertiary amines fourth-generation, hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers. Chemical reduction these composites yields stable, fairly monodisperse, water-soluble DECs having sizes on order 1.9 +/- 0.4 nm. Evidence that nanoparticles comes...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Organic Materials Suitable for Use in Chemical Sensor ArraysRichard M. Crooks and Antonio J. RiccoView Author Information Department of Chemistry, Texas A&M University, P.O. Box 300012, College Station, 77842 Microsensor R&D Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1425 Cite this: Acc. Chem. Res. 1998, 31, 5, 219–227Publication Date (Web):April 17, 1998Publication History Received20 August 1997Published online17...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTInteractions between Organized, Surface-Confined Monolayers and Vapor-Phase Probe Molecules. 10. Preparation Properties of Chemically Sensitive Dendrimer SurfacesMona Wells Richard M. CrooksView Author Information Department Chemistry, Texas A&M University College Station, 77843-3255 Cite this: J. Am. Chem. Soc. 1996, 118, 16, 3988–3989Publication Date (Web):April 24, 1996Publication History Received12 January 1996Published online24 April...

Au colloids in the 2−3-nm size regime were prepared by situ reduction of HAuCl4 presence poly(amidoamine) dendrimers. The dendrimers encapsulate colloids, imparting stability to aqueous colloidal solutions. nanocomposite materials can be isolated precipitation. dendrimer generation used synthesis controls resultant colloids: lower-generation give rise larger colloids. characterized infrared and UV−vis spectroscopy transmission electron microscopy.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTElectrochemistry Using Single Carbon NanotubesJoseph K. Campbell, Li Sun, and Richard M. CrooksView Author Information Department of Chemistry P.O. Box 30012, Texas A&M University College Station, 77842-3012 Cite this: J. Am. Chem. Soc. 1999, 121, 15, 3779–3780Publication Date (Web):April 2, 1999Publication History Received4 January 1999Published online2 April inissue 1...

This work represents the first study of mass transport phenomena within a nanotube and thus holds promise as means probing properties interiors. Multiwall carbon nanotubes are used templates to fabricate single-pore membranes. These membranes better experimental models for testing specific predictions theories than arrays nanopores because they require fewer adjustable parameters have well-defined geometry chemical structures. Using polystyrene particles probes, we demonstrate that...

We report that dendrimer-encapsulated Pd nanoparticles having a diameter of approximately 1.7 nm are effective and general catalysts for coupling aryl halides to organostannanes (the Stille reaction) under mild conditions. The significant results this study the reaction is catalyzed by in very good yield, aqueous solution at 23 degrees C, using only 0.100 atom % as catalyst.