Design and Synthesis of Molecular Reactors for the Preparation of Topologically Trapped Gold Cluster

Abstract

DMF (20 mL). To the solution thus obtained was added dropwise over 10 min sulfur monochloride (0.040 mL, 0.50 mmol) in dry DMF (5.0 mL) under nitrogen at ±50 C. While being stirred overnight the reaction mixture was allowed to reach room temperature, and the resultant brown precipitate was filtered and washed with methanol. The crude product was purified by column chromatography (silica gel, carbon disulfide) and recrystallized from carbon disulfide/hexane (1:2, v/v) to afford 64.0 mg (0.141 mmol) of airstable black plate-like crystals in 27 % yield. mp (decomp.) 183.0±183.6 C. IR (KBr) [cm ±1 ] n = 2921, 2853, 1508, 1456, 959, 915, 768, 511, 468. 1 H NMR (CS 2 /CDCl 3 ) (5:1, v/v) [ppm] d = 3.29 (m, 4H). Anal. Calcd. for C 8 H 4 S 11 : C 21.25, H 0.92, S 78.19; found, C 21.22, H 0.89, S 77.89.Crystallographic Data Collection and Structure Determination: X-ray crystal structure analyses were performed for 4 and its ClO 4 ± salt. Their crystal and experimental data are shown in Table 1. Data collection and refinement conditions: Rigaku AFC-5R diffractometer, 296 K, o±2y mode up to 2y = 60, o scan speed 8.0 deg min ±1 , graphite monochromated Mo Ka radiation (l = 0.71069 ). No decay correction was applied. The structure was solved by a direct method (SHELXS86) [12]. The atomic scattering factors were taken from the International Tables for X-ray Crystallography [13]. Full-matrix least-squares refinements with all non-hydrogen atoms anisotropic were carried out for 4 and 4×ClO 4 ×(chlorobenzene) 0.5 except for the solvent molecule of the perchlorate salt, which was refined isotropically. Hydrogen atoms were included, but their positions were not refined.The potential application of monodisperse metals and semiconductor colloids in such fields as nonlinear optics, photovoltaic cells, catalysis and new laser technologies has led to research into the preparation and stabilization of nanosized particles. [1±8] The classical routes comprise

Functionalized gold nanoparticles: Synthesis, structure and colloid stability

“…The similarities in the preparation of different metal colloids allow the synthesis of mixed-metal particles, which may have functionality different from each individual metal. Metallic nanoparticles can also be capped with various inorganic shells [12][13][14], such as conductive, non-metallic graphite, or semiconductive CdS and they also can be prepared in the form of a hollow sphere. Such "core-shell" or hollow particles have been studied extensively because their properties can differ from those of the core or shell materials.…”

Nanoparticle interaction with model lung surfactant monolayers

“…Polyorganosiloxane (AmorSil20) NPs, which consist of a core-shell NP with polyorganosiloxane nanospheres and polydimethylsiloxane (PDMS) core, and have a non-functional surface and are hydrophobic in nature (Roos et al 1999) (kindly provided by Dr Michael Maskos, Institute for Physical Chemistry, University of Mainz), were dissolved in chloroform to get a concentration of 10 mg ml 21 corresponding to 1.93 Â 10 15 particles ml…”

Crosslinked Spherical Nanoparticles with Core-Shell Topology

“…Analogous to the tracer diffusion studies of Liz-Marzan and Philipse using silica-coated gold clusters [23] (see above), we employed gold-labeled core±shell organosilicon microgels as tracers with enhanced scattering contrast. The synthesis of these particles, published in detail elsewhere, [28] is sketched in Figure 10. Similar to the dye-labeled organosilicon particles, the gold clusters are incorporated after formation of reactive core±shell microgels, i.e., in this case by in-situ reduction of Au 3+ and precipitation of Au within the reactive network.…”

“…[27,29,30] Here, it should be noted that for our gold-doped organosilicon microgels the non-functional shell is used to suppress any negative influence of the gold clusters on the tracer mobility (see above) as well as to control, via its mesh size, the gold cluster morphology by providing a kinetic barrier to diffusion of the gold ions into the reactive core. [28] …”