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The chemical diversity of intrinsically electroactive ionic liquid (IL) phases is extended to redox salts based on ferrocene tethered to imidazolium ions. The intrinsically electroactive ILs are different from the earlier reports, where the ferrocene redox moiety is directly linked to the imidazolium center, rather than being its counterion.

The quantitative the high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and high-resolution TEM measurements are carried out on subnanometer gold clusters that have indicated cluster cores of 13 atoms with average diameters of 0.8 nm. The experiments have provided direct evidence that [Au.sub.13] clusters adopt an icosahedral structure while those with average diameters near 2 nm adopt unrelaxed bonding habits characteristic of the bulk fcc structure.

The synthesis and characterization of two slightly different [Au.sub.13] cluster molecules, [Au.sub.13][[PPh.sub.3].sub.4][[S[(C[H.sub.2]).sub.11]C[H.sub.3]].sub.2][Cl.sub.2] and [Au.sub.13][[PPh.sub.3].sub.4][[S[(C[H.sub.2]).sub.11]C[H.sub.3]].sub.4], are described. The electrochemical and spectroscopic properties of the two [Au.sub.13] cluster molecules are compared with those of a secondary synthetic product and the characterization of sub-nanometer clusters have shown how these [Au.sub.13] clusters display structure not present in the bulk material.

A room-temperature [Au.sub.38] nanoparticle polyether melt is prepared by exchanging poly(ethylene glycol) (PEG) thiolate ligands, HS-C6-[PEG.sub.163], into the organic protecting monolayer of A[u.sub.38][Ph[C.sub.2].sub.24] nanoparticles. The electron hopping dynamics between Au nanoparticles and the mass transport properties of electrolyte ions are studied at room temperature.

A room-temperature redox molten salt for study of electron transfers in semisolid media, based in combining bis(cyclopentadienyl) cobalt with oligomeric polyether counterions is reported. The results support the generality of the proposed model of ionic atmosphere relaxation control of electron transfers in ionically conductive, semisolid materials.

The reaction of the phosphine-protected Au nanoparticle Au(sub 55)[PPh(sub 3)](sub 12)Cl(sub 6) with hexanethiol and other thiols is described. The mass spectrometric results and the thermogravimetric analysis of hexanethiol results in the formation of a preliminary formulation Au(sub 75)(SC(sub 6)H(sub 13)) (sub 40).

A study reports the effects of various organic and inorganic ligands on optical properties of CdSe nanocrystals (NCs) by changes in their photoluminescence and absorbance spectra. The complex of trioctylphosphine with Se atoms on the surface of CdSe NCs was found to be responsible for the trap emission band.

The electrochemical and spectroscopic properties of a well-characterized, synthetically accessible, 1.1 nm diam Au nanoparticle, Au38(PhC2S)24 are discussed. A study on the voltammetry of the Au38 nanoparticles in CH2Cl2 reveals a 1.62 V energy correction of ca. 0.29 V.

The transfer of core metal atoms and ligands of the monolayer shells of monolayer-protected metal cluster (MPC) nanoparticles from one kind of MPC to another is examined. Heterophase ligand exchange and heterophase metal transfer is observed when the reaction is heterophase between C6 Au MPC and tiopronin Ag MPCs.

The synthesis and spectroscopy of three somewhat polydisperse air-stable, water soluble tiopronin (N- 2- mercaptopropionylglycine) monolayer- protected silver clusters (Ag MPC) is presented. The Ag MPCs become organic soluble upon conversion to poly (ethylene glycol) quaternary ammonium salts of the carboxylates of the tiopronin ligand monolayer.

The unprecedented resolution of electrochemically observed quantized double layer (QDL) charging attained with use of reduced solution temperature and with an annealing procedure that produces hexanethiolate monolayer protected gold clusters (C6 MPCs) with a high level of monodispersity in charging capacitance, C(sub CLU), is described.

The rate and extent of ligand place exchange reactions between the hexanethiolate monolayer of Au140 monolayer clusters (C6 MPCs) and dissolved 6-mercapto-1-hexanol thiol increases with increasing positive electronic charge on the Au cluster core. Acid-base studies show that thiolate is more reactive in place exchange reactions than the corresponding thiol.

An attempt is made to characterize tiopronin monolayer-protected gold clusters (MPCs) using NMR spectroscopy and computer modeling techniques. NMR analyses show that the proton and carbon resonances from the tiopronin ligands are split into two components and that the magnitude of the splitting decreases strongly with the number of bonds separating the nucleus from the gold core.

Microband voltammetry is described in undiluted molten salts of Co(II) bipyridine complexes to which short (n=1,2, or 3 units) polypropylene oxide oligomers is applied. It is possible to measure cyclic voltammetric and potential step responses under conditions where the diffusion layer thickness formed in the electrolysis is demonstrated less than the diameter of the Co complex.

A highly viscous room-temperature redox polyether hybrid melt was prepared by combining the hexacyanoferrate(III) with a quaternary ammonium countercation consisting of triethylammonium connected to a poly(ethylene glycol) methyl ether. The microelectrode voltammetry and potential step chronoamperometry in the undiluted melt give an apparent diffusion coefficient of D(sub APP) = 2.5 x 10(super -10) cm(super 2)/s at 20 degree Centigrade.

Monolayer-protected Au clusters (MPCs) have been prepared with mixed monolayers of alkanethiolates and alkanethiolates terminally [Omega]-functionalized with phenothiazine. The mixed monolayer MPCs can contain as many as 10 phenothiazines/MPC; these electron donors are electroactive in rapid, successive one-electron reactions. Surface adsorption of the functionalized MPCs is evident in cyclic voltammetry. Double-potential-step chronocoulometry with incremented potential steps was applied to unfunctionalized hexanethiolate-coated MPCs and to those functionalized with phenothiazine to analyze the coupling between the diffusion-controlled double-layer charging of the MPC cores and the oxidation of the phenothiazine centers. Apparent changes in ordering of the MPC alkanethiolate chains were observed with infrared spectroscopy in solutions of MPCs where alcohol, carboxylic acid, or phenothiazine moieties had been incorporated into the monolayer.

Visible--near-IR luminescence spectra of gold monolayer-protected Au clusters (MPCs) that are similar, irrespective of a 20-fold range of core atoms and different monolayers are discussed. Luminescence can be induced by introducing polar or charged ligands into nonpolar MPC monolayers and by galvanic exchange of Au atoms onto Ag MPC core surfaces with intensities quantitatively proportional to the number of introduced ligands and Au metal atoms.

Gold nanoparticles are the focus of numerous investigations because of their optical, electronic, and chemical properties. The first results for the electron-transfer dynamics of the smallest, most molecular, member (8 kDa) of this transition are provided.

Research describing the process of diffusive transportation of monomeric solutes and micelles in carbon dioxide is presented. Particular attention is given to the technique of selecting ionic surfactants with high conductivity as well as electroactive solutes.

Issues concerning the synthesis and examination of polyether, semisolid, MPEG-based redox molten salts of mixed-valent ruthenium complexes, using electrochemical measurements, and their electron-transfer chemistry are discussed. Analysis of the optically-driven electron transfer process indicates that ion association contributes thermal electron-transfer energy barriers in these redox melts.

Electroactive Polymers and Macromolecular Electronics ELECTRON-TRANSFER ACTIVE (ELECTROACTIVE) POLYMERS represent an emerging class of important conductive materials (1, 2). In the first part of this article we discuss how fundamental [...]

Research was conducted to examine a monolayer-protected Au cluster (MPC) based on a monolayer of thiolated polymer that was chosen for its potential to yield improved core stabilization and to induce aqueous solubility. The objective was to explore a polymer electrolyte nanophase organized around distributed metallic centers. Results demonstrate that a polymeric monolayer has resulted in characteristics that are uniquely different from alkanethiolate MPCs.

The synthesis and chemical properties of nanometer-sized monolayer-protected metal alloy clusters (MPACs), large alloy molecules that were the first to be isolated from solvent-free forms and redissolved without change, were discussed. Electronic spectral analysis characterized the MPACs as typical metal cluster surface plasmon band above an absorbance decreasing from high to low energy due to electron-hole interactions. The findings suggest that the optical and electronic properties of MPACs can be altered and their core metals slightly segregated.

A proportionality of over 1011-fold range of values was found in the heterogeneous rate constants (ko) of the Co(III/II) reaction of Co(II) tri(bipyridine) complexes to their physical self-diffusion coefficients (Dphys). The linear regression plot of ko vs. Dphys is interpreted as a general example of solvent dynamics control over electron transfer rate. The plot shows that Co(III/II) rates are not affected by distance-related tunneling barriers imposed by the polyether shells of the complexes and the insensitivity of the Co(II/I) reaction rate constant to Dphys.

The electron transfer (et) behaviour of purified, 28 kDa core mass, hexanethiolate-protected gold cluster molecules is described. It demonstrates the link between tip-based tuneling spectroscopy of a single Au cluster molecule on a metal surface, and cyclic pulse voltammetry of groups of the same clusters. The voltammetry gives the first example of a solution-phase coulomb staircase of a group of nanoparticles.

Alpha-functionalized alkanethiolate-stabilized gold cluster compounds are synthesized using a strategy based on place exchange reactions that occur when an alpha-substituted alkanethiol is added to an alkanethiolate-cluster solution. The multi-electron electrochemical reactions of the ferrocenyl cluster molecule are determined. The functionalization of the compounds is expected to pave the way for their use as multifunctional reagents, catalysts and chemical sensors.

Molecule scale diffusion studies of the metal complex (CO(bpy(pppm)2)3)(super 2+)(I(super 2+)) in its room-temperature salt with (ClO4-)2 reveal the reactant diffusion rate and the electrodes control electrochemical reaction rate. The diffusion constants are larger for complexes near the electrode. This may be due to the disruption of neutrality in a diffusion layer, variation in structure or kinetics, electron hopping between faces and variation in interfacial layer components.

The mechanism by which ordinarily crystalline materials are converted into room-temperature melts by the covalent linkage of short oligo (ethylene glycol) chains to cobalt tris(bipyridine) complexes (I), tetrathiafulvalene, tetraphenylporphyrin and ferrocenecarboxylate is explored. These melts freely dissolve electrolytes such as LiClO4 to produce ionically conductive melts. Intrinsic ionic conductivity is observed for compound I, which is a novel electroactive molten salt.