Grafting and Thermal Stripping of Organo‐Bimetallic Clusters on Au Surfaces: Toward Controlled Co/Ru Aggregates

Abstract

The controlled stoichiometry of heterometallic carbonyl clusters make them attractive precursors for the stabilization of bare metal alloy clusters for magnetic applications. The mixed-metal molecular cluster [RuCo3(H)(CO)12] has been functionalized with the phosphane-thiol ligand Ph2PCH2CH2SH to allow subsequent anchoring on a gold surface. The resulting tetrahedral cluster [RuCo3(H)(CO)11(Ph2PCH2CH2SH)] (1) has been characterized by X-ray diffraction and the P-monodentate ligand is axially bound to a cobalt center and trans to the ruthenium cap. This synthesis also yielded the product of oxidative coupling, in which two SH groups were coupled intermolecularly to give a disulfide ligand that links two tetrahedral cluster units in [{RuCo3(H)(CO)11(Ph2PCH2CH2S)}2] (2). This cluster has also been characterized by X-ray diffractions studies. After deposition of 1 on a Au(111) surface by self-assembly, the carbonyl ligands were stripped off by thermal annealing in ultra-high vacuum (UHV) to form a metallic species. X-ray photoelectron spectroscopic measurements performed as a function of the annealing temperature show that the cobalt and ruthenium centers converge towards metallic character and that the stoichiometry of the alloy is retained during the annealing process. Preliminary X-ray absorption spectroscopy (XAS) synchrotron experiments indicate that clusters 1 and 2 behave similarly, which is consistent with the retention of their tetrahedral units on the gold surface after transformation of the thiol function or breaking of the disulfide bond to form Au--S bonds, respectively, has occurred.

Thioether-terminated nickel(ii) coordination clusters with {Ni6} horseshoe- and {Ni8} rollercoaster-shaped cores

“…13 (v) The tetrahedral mixedmetal {RuCo 3 } carbonyl clusters functionalised with the phosphane-thiol ligands were studied on a gold surface by STM, XPS and X-ray absorption spectroscopy. 14 (vi) The chemical, structural, and thermodynamic characterisation of the mononuclear Pt(II) cis-complexes and the heterotrinuclear {Co 2 Pt} clusters containing N-substituted bis(diphenylphosphanyl) amine ligands with the pendant thiobenzyl ester groups 15 as well as a trinuclear Ag(I) complex and a Ag(I) coordination polymer with a thioether function in their short-bite diphosphine ligands 16 were described. (vii) Sulfur-assisted phenyl migration from phosphorus to platinum in molecular {PtW 2 } and {PtMo 2 } clusters with thioether-functionalised short-bite ligands of the bis(diphenylphosphanyl)amine-type was demonstrated.…”

Ion‐Directed Coordinative Polymerization of Copper(II) Pyridyl‐Alcohol Complexes Through Thiane Functionalities

“…The role of thio functionalities in coordination chemistry [1][2][3][4][5][6][7] and its interplay with materials and surface science [8][9][10][11][12][13] continues to receive much attention. In particular, ligands augmented with structurally exposed thio substituents are used to generate metal complexes of interest for example catalysis [14][15][16] and molecular electronics and spintronics.…”

Assembling metals and clusters around an octaphosphine ligand based on N-substituted bis(diphenylphosphanyl)amines: structural characterization of dendrimer-like Co12and Co16branched clusters

“…Future objectives are to deposit such dendrimer-like nanoobjects on surfaces, 15 prepare metal particles and compare their physical properties with those of nanoparticles obtained from the isolated tetrahedral carbonyl clusters. 16 In conclusion, we have reported a stepwise strategy to assemble dendrimer-like Co 12 and Co 16 metal clusters around a polypodal ligand.…”