Alkanethiol cluster

Murray and co-workers have demonstrated that further funetionalization of these nanoparticles can be achieved by place exchange reactions, which occur when an excess of functionalized alkanethiol is added to an alkanethiolate-cluster solution." In this way, a new chemical functionality can be introduced without changes in the... 

Chaki NK, Negishi Y, Tsunoyama H, Shichibu Y, Tsukuda T (2008) Ubiquitous 8 and 29 kDa gold alkanethiolate cluster compounds mass spectrometric determination of molecular formulas and structural implications. J Am Chem Soc 130 8608-8610. doi 10.1021/ja8005379... 

Cerril, R.H., Posdethwaite, T.A., Chen, C.H., Poon, C.D., Tzerzis, A., Hutchinson, A.D., Clark, M.R., Wignall, G., Londono, J.D., Superfine, R., Calvo, M., Johson, C.S., Samulski, E.T. and Murray, R.W. (1995) Monolayers in Three Dimensions NMR, SAXS, Thermal, and Electron Hopping Studies of Alkanethiol Stabilized Gold Clusters. Journal of the American Chemical Society, 117, 12537-12548. 

SAMs of alkanethiols on an Au(l 11) surface are widely used to control surface properties, electron transfer processes and to stabilize nano-clusters [6, 7]. SAMs are formed by chemical bond formation between Sand Au when an Au(l 11) substrate is immersed in a solution containing several mM of alkanethiols for hours to days. Various functions have been realized by using SAM s of alkanethiols on Au substrates as listed in Table 16.1. 

Why do we believe that a Cu monolayer is inserted between SAM and gold substrate The 2D-deposit grows and dissolves extremely slowly. Another indication is that the 2D deposit is very stable and shows no displacement by the scanning tip. Cu clusters on top of an alkanethiol-SAM would be only weakly bound and should be easily pushed away by the tip at higher tunnel currents, very much like metal clusters on a hydrogen-terminated Si(lll) surface, which for that very reason are difficult to image by STM (or AFM [122]). And finally, the cyclic voltammograms (Fig. 33) point to the formation of a buried monolayer . 

Osterloh, F. Hiramatsu, H. Porter, R. Guo, T., Alkanethiol induced structural rearrange ments in silica gold core shell type nanoparticle clusters An opportunity for chemical sensor engineering, Langmuir. 2004, 20, 5553 5558... 

S. J. Green, J. J. Stokes, G. D. Wignall, G. L. GUsh, M. D. Porter, N. D. Evans, and R. W. Murray, Alkanethiolate gold cluster molecules with core diameters from 1.5 to 5.2 nm Core and monolayer properties as a function of core size, Langmuir 14,17—30 (1998). 

While Pb is typically not a useful choice for device top contacts because of its low melting point and soft mechanical characteristics, it is of considerable interest for its superconducting characteristics. There appear to be, however, no reports on Pb deposition on SAMs. In our own preliminary experiments of Pb deposition on Cl6 alkanethiolate SAM on Au/mica from UHV AFM imaging, we observed complete penetration with no top surface cluster formation and continuing penetration into the underlying Au lattice. ... 

Maitani MM, Daniel TA, Cabarcos OM, Allara DL (2009) Nascent metal atom condensation in self-assembled monolayer matrices coverage-driven morphology transitions from buried adlayers to electrically active metal atom nanofilaments to overlayer clusters during aluminum atom deposition on alkanethiolate/gold monolayers. J Am Chem Soc 131 (23) 8016-8029... 

Wang B, Xiao X, Sheng P (2000) Growth and characterization of Au clusters on alkanethiol self-assembled monolayers. J Vac Sci Technol B 18 2351-2358... 

Lando A, Lauwaet K, Lievens P (2009) Controlled nanostructuring of a gold film covered with alkanethiol SAM by low energy cluster implantation. Phys Chem Chem Phys 11 (10) 1521-1525... 

Gold clusters are stabilized by the adsorption of surfactants. Alkanethiols play an important role in this stabilization. 

Scheme 3.5 Ligand exchange reaction of the cluster [Au11(PPh3)gCI3] with -functionalized alkanethiols.

Imahori H, Arimura M, Hanada T, et al. Photoactive three-dimensional monolayers porphyrin-alkanethiolate-stabilized gold clusters. J Am Chem Soc 2001 123 335-6. 

The giant clusters could be reproducibly formed starting from Pd561 nanocrystals in water, ethanol and ethanol-water mixtures and from sols with very different concentrations of the nanocrystals. It is possible that the formation of the giant clusters is facilitated by the polymer shell that encases them. Unlike Pd nanocrystals coated with alkanethiols, which self-assemble to form ordered arrays, the polymer shell effectively magnifies the facets of the metallic core, thereby aiding a giant assembly of the nanocrystals. The surface properties of the polymer-coated nanocrystals are clearly more favorable in that the interparticle interaction becomes sufficiently attractive. 

Hanada Y. Nishimura 1. Yamazaki Y. Sakata S. Fukuzumi, Photoactive Three-Dimensional Monolayers Porphyrin-Alkanethiolate-Stabilized Gold Clusters. J. Am. Chem. Soc. 2000,... 

S. R. Johnson S. D. Evans S. W. Mahon A. Ulman, Alkanethiol Molecules Containing an Aromatic Moiety Self-Assembled onto Gold Clusters. Langmuir 1997, 13, 51-57. 

Murray and co-workers have also demonstrated that the variation in Au-core sizes leads to a transition from metal-like double layer capacitive charging for larger sized particles to redox-like charging for smaller particles ranging between 1.1 nm and 1.9 nm diameter [105] (Figure 20.8). Gold particles stabilized with short chain alkanethiolate monolayers have been used in this study. The capacitance of the clusters is calculated using the concentric sphere capacitance model ... 

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