Inorganic Chemistry Commons^™

Distance-Dependent Electron Hopping Conductivity And Nanoscale Lithography Of Chemically-Linked Gold Monolayer Protected Cluster Films, Francis P. Zamborini, Laura E. Smart, Michael C. Leopold, Royce W. Murray

Chemistry Faculty Publications

Films of monolayer protected Au clusters (MPCs) with mixed alkanethiolate and ω-carboxylate alkanethiolate monolayers, linked together by carboxylate–Cu2+–carboxylate bridges, exhibit average edge-to-edge cluster spacings that vary with the numbers of methylene segments in the alkanethiolate ligand as determined by a combined atomic force microscopy (AFM)/UV-Vis spectroscopy method. The electronic conductivity (σEL) of dry films is exponentially dependent on the cluster spacing, consistent with electron tunneling through the alkanethiolate chains and non-bonded contacts between those chains on individual, adjacent MPCs. The calculated electronic coupling factor (β) for tunneling between MPCs is 1.2 Å−1, which is similar to …

Growth, Conductivity, And Vapor Response Properties Of Metal Ion-Carboxylate Linked Nanoparticle Films, Michael C. Leopold, Robert L. Donkers, Dimitra Georganopoulou, Megan Fisher, Francis P. Zamborini, Royce W. Murray

Chemistry Faculty Publications

Nanoparticles of metals (Au, Ag, Pd, alloys) in the size range 1–3 nm diameter can be stabilized against aggregation of the metal particles by coating the metal surface with a dense monolayer of ligands (thiolates). The stabilization makes it possible to analytically define the nanoparticle composition (for example, Au140(hexanethiolate)53, I) and to elaborate the chemical functionality of the protecting monolayer (for example, Au140(C6)35(MUA)18, II, where C6 = hexanethiolate and MUA = mercaptoundecanoic acid). Network polymer films (IIfilm) on interdigitated array electrodes can be prepared from II, based on cation coordination (i.e., Cu2+, Zn2+, Ag+, methyl viologen) by the …

Dramatic Nondipole Effects In Low-Energy Photoionization: Experimental And Theoretical Study Of Xe 5s, Oliver Hemmers, Renaud Guillemin, E. P. Kanter, B. Krassig, Dennis W. Lindle, S. H. Southworth, R. Wehlitz, J. Baker, A. C. Hudson, M. Lotrakul, D. Rolles, Wayne C. Stolte, I. Tran, A. Wolska, S. Yu, M. Ya Amusia, K. T. Cheng, L. V. Chernysheva, W. R. Johnson, S. T. Manson

Environmental Studies Faculty Publications

The Xe 5s nondipole photoelectron parameter γ is obtained experimentally and theoretically from threshold to ∼200  eV photon energy. Significant nondipole effects are seen even in the threshold region of this valence shell photoionization. In addition, contrary to previous understanding, clear evidence of interchannel coupling among quadrupole photoionization channels is found.

E1-E2 Interference In The Vuv Photoionization Of He, E. P. Kanter, B. Krassig, S. H. Southworth, Renaud Guillemin, Oliver Hemmers, Dennis W. Lindle, R. Wehlitz, M. Ya Amusia, L. V. Chernysheva, N. L. S. Martin

Environmental Studies Faculty Publications

We have measured the forward-backward asymmetry of photoelectron angular distributions produced in the vacuum ultraviolet photoionization of helium. This asymmetry, a consequence of the breakdown of the dipole approximation, measures the real part of the ratio of the quadrupole and dipole matrix elements. In the autoionization region, the strong energy dependence of the asymmetry permits an experimental separation of the ratio of those magnitudes from their phase difference. We experimentally determined the Fano parameters of the 2p²¹D₂ quadrupole resonance, and report improved values of the width Γ and line profile parameter q from those previously available …

Reactions Of Boranes And Metallaboranes With Phosphines, Lawrence Barton, Oleg Volkov, Mitsuhiro Hata, Paul Mcquade, Nigam Rath

Chemistry & Biochemistry Faculty Works

This paper reports extensions of the well-established field of phosphine–borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2 [(Fe(C5H4)2]}, are formed in reactions of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9]. Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10] and [9,9-(PPh3)2-nido-9,7,8-RhC2B8 H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(µ-dppm)]-closo -1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron vertices in the cage, [1,1-(ç2-dppe)-3-(ç1-dppm)-closo-1,2-RhSB 9H8], a mixed ligand system, and {9,9-ç2-[(ç2-BH3)PPh2PCH2 PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described as is an example of …

Argon Eximer Emission From High-Pressure Microdischarges In Mental Capillaries, R. Mohan Sankaran, Konstantinos P. Giapis, Mohamed Moselhy, Karl H. Schoenbach

Bioelectrics Publications

We report on argon excimer emission from high-pressure microdischarges formed inside metal capillaries with or without gas flow. Excimer emission intensity from a single tube increases linearly with gas pressure between 400 and 1000 Torr. Higher discharge current also results in initial intensity gains until gas heating causes saturation or intensity drop. Argon flow through the discharge intensifies emission perhaps by gas cooling. Emission intensity was found to be additive in prealigned dual microdischarges, suggesting that an array of microdischarges could produce a high-intensity excimer source.

Chlorobenzenes And Chloronitrobenzenes Interaction With Iron (O), Manuel Alejandro Serratos

Masters Theses

Degradation of chlorobenzene, dichlorobenzenes and chloronitrobenzenes (ClB, x-Cl2B and x-ClNO2B) was tested by trying to make them react with metallic iron, Fe (0), in water solvent.

The experiments consisted of optimizing the parameters of the reactions (like minimum mass of iron needed) and analytical detection conditions. Analytical techniques used were gas and liquid chromatography (GC and HPLC), mass spectrometry (MS) and UV-Vis spectroscopy.

No substances other than the initial ClB and x-Cl2B were detected in their tests with Fe (0) after shaking for periods of up to three days, although 10%weight average decreases in concentration were observed.

The ClNO2B isomers …

Stabilization Of Polyvinyl Chloride By Some Conducting Polymers, Amit Shah, Brian C. Berry, Ali U. Shaikh

Journal of the Arkansas Academy of Science

No abstract provided.

Simulations Of Quantized Double Layer Charging Voltammetry Of Poly Disperse And Mono-Disperse Monolayer Protected Clusters, Deon T. Miles, Michael C. Leopold, Jocelyn F. Hicks, Royce W. Murray

Chemistry Faculty Publications

This paper describes simulated differential pulse voltammetry (DPV) of quantized double-layer charging (QDL) in poly-disperse monolayer-protected gold cluster (MPC) solutions. The simulation accounts for the voltage spacing between QDL peaks with a concentric sphere capacitor model, in which core sizes, and the relative proportion of each size, are input using transmission electron microscopy (TEM) data. MPC diffusion coefficients are estimated from hydrodynamic radii, and peaks are broadened to account for DPV pulse height effects. The smallest MPCs are omitted from the simulation because electrochemical HOMO/LUMO gap information is uncertain. The largest ones are shown to produce the underlying DPV current …