Monoorganotin-polyoxometal-compounds. Part IV: Na2[(PrSn3)(OV)4O10(OH)3]·5H2O·3DMSO, a novel branched tetravanadate(V) stabilized by a trimeric monoorganotin-oxo-hydroxo unit

Via self-assembly of the molecular precursors sodium orthovanadate and isopropyltin-dihydroxide-chloride the unprecedented organic-inorganic hybrid polyoxoanion [(ⁱPrSn)₃(OV)₄O₁₀(OH)₃]²⁻ was synthesized in dimethylsulfoxide (DMSO) and isolated as its sodium salt Na₂[(ⁱPrSn)₃(OV)₄O₁₀(OH)₃]·5H₂O·3DMSO. This spherical nanosized anion is composed of two different structural subunits, a well-known trinuclear monoorganotin-polyoxo-hydroxo unit with octahedrally coordinated tin atoms and a new open-chain, branched isopolyoxo tetravanadate(V) with tetrahedrally coordinated vanadium atoms.     

Domains in biological membranes

Our current view on biological membranes has gradually evolved from the influential fluid mosaic model of the early 1970s to a distinctively more complex picture. Biological membranes are now assumed to encompass multiple membrane domains and a plethora of protein-lipid and protein-protein interactions that compartmentalize and temporarily order what has originally been envisioned to be mostly random. In this minireview, we will first highlight some structural principles that govern membrane domain formation and permit a classification of membrane domains. We will then focus on the still controversial issue of lipid-based membrane domains, or lipid rafts, and discuss recent advances in detecting these enigmatic structures in living cells. Finally we will evaluate biochemical approaches to characterize lipid rafts and discuss their contribution to the emerging topic of lipid raft diversity     

Structures and Energetics of Platinum–Cobalt Bimetallic Clusters

Platinum–cobalt bimetallic clusters (N=11–15) were modeled by a many-body Sutton-Chen (SC) potential. The basin-hopping algorithm and Monte Carlo (MC) energy minimization were used to determine the global minima of bimetallic clusters. The structural changes with cluster size were observed. Most of the structures had built on icosahedral packing. Second energy difference analyzes were performed to investigate the relative stability of a cluster with respect to its size and composition. The dependence of energetics and structures on size and composition is discussed.     

Thiophenolate clusters as potential nanosized building blocks for zinc-based nanocomposite materials: synthesis and characterization

The synthesis, the spectroscopic and structural characterization of different thiophenolate-capped zinc clusters are reported and described. In particular, different reactions of 4-chlorobenzenethiol with zinc salts yield the clusters [Me₄N][Et₃NH][Zn₄(μ-S-C₆H₄-Cl)₆(S-C₆H₄-Cl)₄] (2a), [Et₃NH]₂[Zn₄(μ-S-C₆H₄-Cl)₆(S-C₆H₄-Cl)₄] (2b), and [Me₄N]₂[Zn₄(μ-S-C₆H₄-Cl)₆(S-C₆H₄-Cl)₄] (2c), and also the thiophenolate derivative [Et₃NH]₂[Zn₄(μ-S-C₆H₅)₆(S-C₆H₅)₄] (1b) was obtained.The nanosized thiophenolate-capped clusters were investigated by ¹H and ¹³C NMR, elemental analysis, and electrospray ionization (ESI) mass spectrometry. NMR experiments provided insights into the dynamic behaviour of the clusters. The thermal decomposition patterns of 2c were analyzed in air as well as in nitrogen, indicating the formation of zinc oxide and metallic zinc, respectively. The X-ray structure of 2a revealed that the cluster core consists of an adamantane-like framework analogous to those realized in many other M₄(SR)₁₀ metal complexes.     

Synthesis, characterization and optical properties of tin oxide nanoclusters prepared from a novel precursor via thermal decomposition route

As a new precursor, [bis(2-hydroxy-1-naphthaldehydato)tin(II)]; ([Sn(HNA)₂]), complex was used in thermal decomposition process for the synthesis of tin oxide (SnO₂) nanoclusters. The steric hindrance of the precursor raises the need of using co-surfactant, therefore oleylamine (C₁₈H₃₇N) was applied as the only surfactant of the reaction. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. Also the novel precursor was thermal treated in solid-state reaction in different temperature, 400, 500, and 600 °C. Synthesized tin dioxide nanoclusters with tetragonal phase, have average size of 1.5-4 nm. Finally, optical properties of the products were examined and investigated by photoluminescence spectra.     

Luminescence and simulation of mixed metal nanoclusters of dicyanoargentate(I) and dicyanoaurate(I) in alkali halides

Heterometallic and homometallic nanoclusters of [Ag(CN)₂]⁻ and [Au(CN)₂]⁻ doped in NaCl, KCl, and NaBr exhibit interesting photophysical phenomenon that are related to the variety of sizes, orientations, and compositions these clusters adopt. Samples of various dopant-host systems have been grown and analyzed with luminescence spectroscopy. In order to predict what types of clusters are in these different systems, an atomistic surface model has been developed that probes the energetics of these clusters as they first form at surface kink sites. An order of preference in mixed-metal systems for heterometallic cluster formation over homometallic cluster formation, NaBr > NaCl > KCl, is predicted which agrees with findings on heterometallic cluster peaks in the luminescence spectra. Structural orientations are predicted to be very different in heterometallic clusters as opposed to homometallic clusters.