Electronic structure and bonding of the metal cluster compound Au55(PPh3)12Cl6

Abstract

We discuss the electronic structure, bonding and physical properties of the gold cluster compound Auss(PPh3)l~C16.Results from our experimental measurements, including EXAFS, specific heat, MSssbauer, UV-visible and photoelectron spectroscopy, are combined with those of other work to form a consistent physical picture of the system. The bonding in Anss(PPh3)I~CI6 is much more delocalised and nondirectional than in smaller gold cluster molecules. The Au~s cluster exhibits a substantial degree of metallic bonding, while displaying some of the characteristics of a discrete energy level spectrum.

Metal-cluster compounds: Model systems for nanosized metal particles

“…The isomer shift (IS) and quadrupole splitting (QS) parameters obtained from these MES spectra for the surface sites are very different from the bulk-metal values, being close to literature values for nonconducting metal salts. [14][15][16] For Au 55 , the parameters for the 13 inner-core atoms were already close to but not yet equal to the bulk values. Quite recently, we have been able to extend the MES experiments to Pt 309 .…”

Selective Immobilization of Nanoparticles on Surfaces by Molecular Recognition using Simple Multiple H‐bonding Functionalities

“…The energy resolution was set to 1.5 eV to minimize data acquisition time and the photoelectron take-off angle (TOA) was 37°. All binding energies were referenced to the Au 4f 7/2 core level at 83.8 eV [51]. The base pressure in the spectrometer was in the low 10 -9 mbar range.…”

Electronic and Geometric Structure of the Cluster Compound Au55[P(C6H5)3]12Cl6. A Computational Study

“…As a cuboctahedron features 12 corners and 6 facets, it is suggestive to assign the phosphine ligands to corner sites and the chlorine ligands to locations at the centers of the (100) facets [9]. The Au 55 cluster compound did not yield crystals suitable for X-ray crystallographic studies [10], but extended X-ray fine structure spectroscopy (EXAFS) furnished Au-Au nearestneighbor distances of 275 -280 pm [11 -13]. The result Au-Au = (278.5 ± 0.3) pm with the smallest error range [13] agrees very well with the average nearest-neighbor distance, 279 pm, calculated with the local density approximation (LDA) for a bare cuboctahedral cluster Au 55 [14]; the corresponding value for bare Au 55 with icosahedral symmetry constraints was 281 pm [14].…”

“…A notable example is the cluster compound assigned as Au 55 [P(C 6 H 5 ) 3 ] 12 Cl 6 to which this study is devoted [9]. In fact, it was proposed [9,10] that clusters of a specific nuclearity are generated when one reduces (C 6 H 5 ) 3 PAuCl with B 2 H 6 in benzene at 50 • C. Stable monodisperse cluster systems of this size are quite rare [1,2], yet very interesting for building up nanostructured systems with precise size-dependent properties. 0932-0776 / 09 / 1100-1246 $ 06.00 c 2009 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com Originally, a cuboctahedral structure was postulated for Au 55 [P(C 6 H 5 ) 3 ] 12 Cl 6 [9].…”