Iron Wheels on Silicon:  Wetting Behavior and Electronic Structure of Adsorbed Organostannoxane Clusters

Abstract

Atomic force microscopy and synchrotron radiation (SR) spectroscopy have been used to study the wetting behavior and electronic structure of thin films of a novel organometallic cluster--[BuSn(O)OC(O)Fc]6 ("Fc" = ferrocenyl)--on silicon substrates. This cluster comprises six ferrocene units connected to a stannoxane central core--"an iron wheel on a tin drum" (V. Chandrasekhar; et al. Angew. Chem., Int. Ed. 2000, 39, 1833). Thin films spin-cast onto native oxide-terminated silicon readily dewet the substrate. We have utilized advanced image analysis techniques based on Minkowski functionals to provide a detailed quantitative analysis of the morphology of the stannoxane overlayers. This analysis shows that the dewetting patterns are rather far removed from those expected to arise from a simple Poisson distribution of centers, and we discuss the implications of this finding in terms of nucleated and spinodal dewetting. Variations in both the surface roughness and the in-plane correlation length have been followed as a function of annealing time to probe the surface dewetting dynamics. SR valence band photoemission illustrates that the highest occupied molecular orbital (HOMO) of the cluster is found 2 eV below the Fermi level. Fe 2p --> 3d and Sn 3d --> 5p resonant photoemission spectroscopy have been used to enhance the cross sections of the partial density of states associated with the Fe and Sn atoms. Sn atoms make a large contribution to the HOMO of the cluster, whereas the Fe atoms are associated with an electronic environment seemingly very similar to that in the "parent" ferrocene molecule.

Dewetting-mediated pattern formation in nanoparticle assemblies

“…Concerning us here, due to their crystallographic statistical indistinguishability one cannot be sure that a given nanoparticle cellular network has formed through a nucleation and growth process as opposed to Bénard-Marangoni convection, but it is believed to be the process at play for the majority of experimentally observed cellular morphologies since Bénard-Marangoni convection only occurs within a narrow window of parameter space. Since these pattern formation mechanisms are primarily determined by properties of the solvent and the local environment, the resultant pattern morphologies can be observed for a range of solutes, including, for example, organometallic clusters [39] and collagen [40].…”

Lanthanide hydroxide cubane clusters anchoring ferrocenes: model compounds for fixation of organometallic fragments on a lanthanide oxide surface

“…11 Not only are these multimetallic clusters aesthetically appealing, they also find applications in materials research as reported in the recent literature. 12 In spite of their enormous potential, only a few molecular clusters based on main group 9,11 and transition metal 10 anchoring ferrocenes have been reported so far, whereas their lanthanide counterparts remains completely unexplored. Hence, we were interested in synthesizing air stable multiferrocene assem- blies based on a lanthanide oxygen cluster core.…”

Luminescence and Electrochemical Properties of Organostannoxane Coordination Polymer Based on Ferrocenyl-2-Cyano Carboxylate Ligand

“…The compound was characterized by FT-IR, 1 H and 13 C NMR. It is further supported by absorbance spectra shows high-energy ligand-centred π-π * electronic transition and metal ligand charge transfer.…”

“…Organometallic polymers have been attracting considerable attention in recent years with a view to generating new materials with interesting electrochemical, electronic and magnetic properties [1,2]. In particular, the ferrocene appended stannoxane frameworks are interest due to electrochemically inertness and do not interfere with the electrochemical properties of the peripheral ferrocene moiety [3][4][5].…”