ABSTRACT
The assembly of 3D nanoscale structures of plasmonic nanoparticles (NPs) holds great promise for achieving enhanced optical and electronic properties. This type of materials exhibits a large number of surface hot spots, while offering the possibility for synergetic effects to be observed. Herein, a facile, yet powerful, strategy to fabricate 3D mesoporous networks of copper NPs decorated with graphite layers (denoted as Cu/G) is demonstrated by using a polymer-assisted self-assembly method. After thermal processing, the resulting Cu/G-linked networks retain an open and interconnected porosity with a large surface area (up to 90â m2 g-1 ) and narrow pore size distribution (ca. 4.3â nm in size). Owing to these characteristics, Cu/G assemblies behave as high-performance surface-enhanced Raman scattering (SERS) probes for the detection of analytes in very low concentrations. The substrates comprise low-cost, environmentally benign materials and show promise for chemical and biological sensing applications.
ABSTRACT
The gold-catalyzed hydration of 2-phenyl- or 2,2-diphenylcyclopropyl acetylene, sensitive probes to trace the formation of vinyl carbocations, provides exclusively the corresponding cyclopropyl methyl ketones. On the other hand, in the Ag(I)- or Fe(III)-catalyzed hydration, a profound vinyl carbocationic character appears in the initially formed metal-alkyne complexes, as judged by the partial (Ag(+)) or exclusive (Fe(3+)) formation of allene-type rearrangement products. These findings provide clear evidence for subtle electronic differences in metal-alkyne complexes, including Au(I or III), Ag(I), Fe(III), and Hg(II).
