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Abstract: Here, we report the synthesis and near‐infrared photoluminescence properties of small‐diameter (∼2–3 nm) silver and copper nanoparticles. Periodic trends in nanoparticle quantum yields, observed lifetimes, and emission peak features are studied and compared to each other as well as to previously reported small diameter gold nanoparticles. These trends are distinct from optoelectronic features observed from either their cluster (4–100 atoms) or larger NP (diameter >5 nm) counterparts. Taken together, the successful synthesis and characterization of these materials introduces potential alternatives to small, Au‐based nanoparticles in photoluminescence‐driven applications such as bio‐labeling and sensing, as well as provides additional insight into particle properties at this important size range between molecular and bulk materials. [ABSTRACT FROM AUTHOR]

We report the use of gold nanoparticle surface chemistry as a tool for site-selective noble metal deposition onto colloidal gold nanoparticle substrates. Specifically, we demonstrate that partial passivation of the gold nanoparticle surface using thiolated ligands can induce a transition from linear palladium island deposition to growth of palladium selectively at plasmonic hotspots on the edges or vertices of the underlying particle substrate. Further, we demonstrate the broader applicability of this approach with respect to substrate morphology (e.g., prismatic and rod-shaped nanoparticles), secondary metal (e.g., palladium, gold, and platinum), and surface ligand (e.g., surfactant molecules and n-alkanethiols). Taken together, these results demonstrate the important role of metal-ligand surface chemistry and ligand packing density on the resulting modes of multimetallic nanoparticle growth, and in particular, the ability to direct that growth to particle regions of impact such as plasmonic hotspots. [ABSTRACT FROM AUTHOR]

Copper-containing nanomaterials are attractive due to the natural abundance, low cost, and unique catalytic properties of copper metal. Copper may also be used as a representative system to study the formation of mixed metal nanoparticles containing 3d transition metals. These elements pose challenges to traditional metal nanoparticle synthesis strategies due to competing formation of both oxides and hydroxides, depending on metal identity. Here, we analyze copper deposition pathways on gold nanoprism substrates using a combination of electron microscopy and X-ray photoelectron spectroscopy techniques, demonstrating conditions for both core@shell and island growth modes. Elemental analysis by X-ray photoelectron spectroscopy and Auger electron spectroscopy indicate that the final nanoparticle products contain metallic copper. Together, these results elucidate important trends for incorporating 3d transition metals into traditional colloidal syntheses of multimetallic nanostructures. [ABSTRACT FROM AUTHOR]

Nanoscale platinum materials are essential components in many technologies, including catalytic converters and fuel cells. Combining Pt with other metals can enhance its performance and/or decrease the cost of the technology, and a wide range of strategies have been developed to capitalize on these advantages. However, wet chemical synthesis of Pt-containing nanopartides (NPs) is challenging due to the diverse metal segregation and metal-metal redox processes possible under closely related experimental conditions. Here, we elucidate the relationship between Pt(lV) speciation and the formation of well-known NP motifs, including frame-like and coreshell morphologies, in Au-Pt systems. We leverage insights gained from these studies to induce a controlled transition from redox to surface chemistry-mediated growth pathways, resulting in the formation of Pt NPs in epitaxial contact and linear alignment along a gold nanoprism substrate. Mechanistic investigations using a combination of electron microscopy and 195Pt NMR spectroscopy identify Pt(lV) speciation as a crucial parameter for understanding and controlling the formation of Pt-containing NPs. Combined, these findings point toward fully bottom up methods for deposition and organization of NPs on colloidal plasmonic substrates. [ABSTRACT FROM AUTHOR]

Seedlessinitiation has been used as a simple and sustainable alternativeto seed-mediated production of two canonical anisotropic gold nanoparticles:nanorods and nanoprisms. The concentration of reducing agent duringthe nucleation event was found to influence the resulting productmorphology, producing nanorods with lengths from 30 to 630 nm andtriangular or hexagonal prisms with vertex-to-vertex lengths rangingfrom 120 to over 700 nm. The seedless approach is then used to eliminateseveral chemical reagents and reactions steps from classic particlepreparations while achieving almost identical nanoparticle productsand product yields. Our results shed light on factors that influence(or do not influence) the evolution of gold nanoparticle shape andpresent a dramatically more efficient route to obtaining these architectures.Specifically, using these methods reduces the total amount of reagentneeded to produce nanorods and nanoprisms by as much as 90 wt % and,to the best of our knowledge, has yielded the first report of spectroscopicallydiscernible, colloidal gold nanoplates synthesized using a seedlessmethodology. [ABSTRACT FROM AUTHOR]

The article presents an undergraduate experiment regarding the synthesis of laurolactam from cyclododecanone through Beckmann rearrangment. It states that the experiment will increase the knowledge of students about Beckmann rearrangment, reaction mechanisms and catalytic cycles. It emphasizes the reinforcement of laboratory safety precautions in dealing with the solvents.