In this paper it is demonstrated that the stabilizing effect of linear alkanes can be utilized to achieve
very high stability in the adsorption and assembly of planar organic molecules on inert surfaces under ambient
conditions, by direct deposition from solutions. Using peripherally alkylated phthalocyanines and porphyrins
as the examples, optimal resolutions can be achieved with complex molecular systems. Submolecular features
of the molecular cores and the interdigitated alkyl parts are clearly visible. Distinctly different packing symmetries
were also observed and could be attributed to the intermolecular and adsorbate−substrate interactions.
Appreciable contrast variations were also recorded with changing bias voltages. This approach could be adapted
to the studies of other molecules to observe submolecular features and could be helpful in obtaining two-dimensional assemblies of monodispersed molecules, especially planar molecules.
New insights into the formation chemistry of chalcogenate-protected metal nanoparticles (NPs) synthesized via the well-known Brust-Schiffrin two-phase method are presented here. On the basis of Raman, NMR, and surface plasmon resonance characterizations, it is concluded that, before the formation of any metal-chalcogen bonds, metal nucleation centers/NPs are first formed inside the inverse micelles of the tetrabutylammonium bromide in the organic solvent, where the metal ions are reduced by NaBH(4). The ensuing formation of the metal-chalcogen bonds between the naked metal NPs inside the micelles and the organo-chalcogen ligands in the organic solvent is the mechanism by which the further growth of the metal core can be controlled. This proposed mechanism is further examined in the formation of Ag and Cu NPs.
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