Planar Iron Hydride Nanoclusters: Combined Spectroscopic and Theoretical Insights into Structures and Building Principles

The controlled assembly of well-defined planar nanoclusters from molecular precursors is synthetically challenging and often plagued by the predominant formation of 3D-structures and nanoparticles. Herein, we report planar iron hydride nanoclusters from reactions of main group element hydrides with iron(II) bis(hexamethyldisilazide). The structures and properties of isolated Fe4 , Fe6 , and Fe7 nanoplatelets and calculated intermediates enable an unprecedented insight into the underlying building principle and growth mechanism of iron clusters, metal monolayers, and nanoparticles.

Synthesis and Reactivity of an Early-Transition-Metal Alkynyl Cubane Mn4 C4 Cluster

While the coordination chemistry of monometallic complexes and the surface properties of extended metal particles are well understood, the control of metal nanocluster formation has remained challenging. The isolation of discrete metal clusters provides an especially rare snapshot at the nanoscale of cluster growth. The synthesis and full characterization of the first early-transition-metal alkynyl cubane and the first μ³ -alkynyl Mn₃ motif are reported.

Perspectives on zeolite-encapsulated metal nanoparticles and their applications in catalysis

Recent strategies for the design of zeolites with unusual architectures and porosities offer many opportunities for the encapsulation of catalysts.

Dual application of Pd nanoparticles supported on mesoporous silica SBA-15 and MSU-2: supported catalysts for C–C coupling reactions and cytotoxic agents against human cancer cell lines

Pd nanoparticles have been supported onto SBA-15 and MSU-2 and present interesting catalytic and cytotoxic properties.

Low-temperature growth of silicon nanotubes and nanowires on amorphous substrates

Silicon one-dimensional (Si 1D) materials are of particular relevance due to their prospect as versatile building materials for nanoelectronic devices. We report the growth of Si 1D structures from quasi-hexagonally ordered gold (Au) nanoparticle (NP) arrays on borosilicate glass (BSG) and SiOx/Si substrates. Using hydrogen instead of oxygen plasma during NP preparation enhances the catalytic activity of AuNPs (diameters of 10-20 nm), enabling Si 1D growth at temperatures as low as 320 degrees C. On BSG, Si nanowires (SiNWs) are identified and reasonable vertical alignment is achieved at 420 degrees C. On SiOx/Si, only Si nanotubes (SiNTs) are obtained right up to 420 degrees C. A mixture of SiNTs and SiNWs is observed at 450 degrees C and only SiNWs grow at 480 degrees C.

Zeolite-confined ruthenium(0) nanoclusters catalyst: record catalytic activity, reusability, and lifetime in hydrogen generation from the hydrolysis of sodium borohydride

Sodium borohydride, NaBH4, has been considered the most attractive hydrogen-storage material for portable fuel cell applications, as it provides a safe and practical means of producing hydrogen. In a recent communication (Zahmakiran, M.; Ozkar, S. Langmuir 2008, 24, 7065), we have reported a record total turnover number (TTON) of 103 200 mol H2/mol Ru and turnover frequency (TOF) up to 33 000 mol H2/mol Ru x h obtained by using intrazeolite ruthenium(0) nanoclusters in the hydrolysis of sodium borohydride. Here we report full details of the kinetic studies on the intrazeolite ruthenium(0) nanoclusters catalyzed hydrolysis of sodium borohydride in both aqueous and basic solutions. Expectedly, the intrazeolite ruthenium(0) nanoclusters show unprecedented catalytic lifetime, TTON = 27 200 mol H2/mol Ru, and TOF up to 4000 mol H2/mol Ru x h in the hydrolysis of sodium borohydride in basic solution (5% wt NaOH) as well. More importantly, the intrazeolite ruthenium(0) nanoclusters are isolable, bottleable, redispersible, and yet catalytically active. They retain 76% or 61% of their initial catalytic activity at the fifth run with a complete release of hydrogen in aqueous and basic medium, respectively. The intrazeolite ruthenium(0) nanoclusters were isolated as black powder and characterized by using a combination of advanced analytical techniques including XRD, HRTEM, TEM-EDX, SEM, XPS, ICP-OES, and N2 adsorption.

Intrazeolite ruthenium(0) nanoclusters: a superb catalyst for the hydrogenation of benzene and the hydrolysis of sodium borohydride

The use of microporous materials with ordered porous structures as the hosts to encapsulate metal nanoclusters has attracted particular interest in catalysis because the pore size restriction could limit the growth of nanoclusters and lead to an increase in the percentage of the catalytically active surface atoms. This letter reports the preparation of ruthenium(0) nanoclusters stabilized by the framework of Zeolite-Y by using a simple, easy, efficient method and their superb catalytic activities in two important reactions: the hydrogenation of arenes (benzene, toluene, o-xylene, mesitylene) and the hydrolysis of sodium borohydride, all at room temperature. Particularly, the intrazeolite ruthenium(0) nanoclusters exhibit unprecedented catalytic activity in the hydrogenation of neat benzene at 22.0 +/- 0.1 degrees C and 40 +/- 1 psig H2 with a record TOF of 1040 mol benzene/mol Ru . h.