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The deuterium NMR spectra of the ternary metal deuterides (TMDs) [Ca.sub.2]Rh[D.sub.5] and [Ca.sub.2]Ir[D.sub.5] has shown that the disorder is dynamic at room temperature. The differential scanning calorimetric study of the transition in [Ca.sub.2]Ir[H.sub.5] has located a reversible phase transition at 284 K with an enthalpy change of 650 J [mol.sup.-1] and entropy change of 2.3 J [K.sup.-1] [mol.sup.-1].

A study to examine the catalytic properties of small clusters of rhodium and of iridium on oxide supports using the hydrogenation reaction of ethene, propene, and toluene was conducted. The results indicated self-inhibition of reaction adsorbed hydrocarbons and differences between ethene hydrogenation and propene hydrogenation that may arise primarily from different adsorbate-adsorbate interactions.

The assembly of Ir4(Co)12 from Ir(CO)2(acac) precursors in the supercages of the zeolite NaY is investigated by extended X-ray absorption fine structures (EXAFS) and in-situ infrared (IR) spectroscopies. The results revealed that conditions of pretreatment of the zeolite significantly affect the chemistry of the intercage cluster assembly of Ir4(Co)12 in zeolites nanopores.

The photoluminescence (PL) dynamics of Ir(ppy)(sub 3)-cored dendrimers with the simple molecule Ir(ppy)(sub 3) in solution, blends, and neat films are discussed. Extensive aggregation of Ir(ppy)(sub 3) molecules is indicated by their rough surface with aggregated region of rodlike structure, as obtained by atomic force microscopy, which suggests that the PL quenchers in neat Ir(ppy)(sub 3) films may be excimers.

It is found that incorporation of SnO2 and Sb2O5 into IrOx not only saved the precious content significantly but also generated a synergic effect to make Ti/IrOx-Sb2O5-SnO2 much more stable. Ternary IrOx-Sb2O5-SnO2 is a promising electocatalyst for O2 evolution.

The nanosized Rulr bimetallic clusters in the NaY zeolite show strong resistance for the agglomeration in 1-atm oxygen and at high temperatures, compared to the Ru/NaY. Nanosized Rulr bimatallic clusters containing of 30-60 atoms can be obtained from the thermal decomposition and reduction with hydrogen of the precursor zeolite containing Ru complex and Ir (NH3)5(H2O)3+ free of chloride.

A general approach is developed for the numerical simulation of square wave anodic stripping voltammetry at hemispherical and uniform planar electrodes based on the backward implicit method. Data is presented for the nature of mercury on the surface of both iridium and copper substrates, obtained by atomic force microscopy.

The citrate-stabilized IrO2 colloid was self-assembled onto an indium tin oxide (ITO) electrode to form a monolayer of the colloidal IrO2 particles when dipped in the colloidal solution. The self-assembly could be achieved by a chemical interactions between carboxylate groups on the citrate stabilizer and hydroxyl groups on the ITO surface to form ester bonds.

Some new types of nonclassical iridium carbonysis formed after CO adsorption on Ir-ZSM-5 are reported. An investigation is conducted based on a Fourier transform infrared spectroscopy and the results are explained by the smaller cationic radius of [Ir.sup.2+], which is associated with a decease of the number of ligands required for coordinative saturation.

The syntheses of bright deep blue emitting mixed ligand Ir(III) complexes comprising two cyclometalating, one phosphine and one cyano, ligands are reported. A firm connection between the nature of the excited states and the physicochemical behavior of the complexes with the different ligand systems is elucidated by correlating the observed crystal structures, spectroscopic properties and electrochemical properties with the theoretical results obtained by the density functional theory (DFT) methods.

Adsorption and reactions of NO on clean and CO-precovered Ir(111) were investigated by means of X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy, infrared reflection absorption spectroscopy and temperature-programmed desorption. Two NO adsoprtion states, indicative of fcc-hollow sites and atop sites, were present on the Ir(111) surface at saturation coverage.

A 3-parameter local hot spot model of gas-surface reactivity is employed to analyze and predict dissociative sticking coefficients for CH4 incident on Ir(111) under varied nonequilibrium and equilibrium conditions. The CH4 dissociative sticking coefficient predicted for Ir(111) surfaces at thermal equilibrium, based on the molecular beam experiments, is roughly four orders of magnitude higher and suggests that substaintial improvements in catalyst turnover rates may be possible.

The kinetic energy dependence of reactions of the late third-row transition metal cation Ir(super +) with H2, D2, and HD is measured using a guided ion beam tandem mass spectrometer. Ir(super +) was found to have a stronger M(super +) -H bond, which can be explained by the lanthanide contraction and relativistic effects that alter the relative size of the valence s and d orbitals.

The adsorption and reaction of acetylene on planar and faceted Ir(210) were studied utilizing temperature-programmed desorption (TPD), Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and high-resolution electron energy loss spectroscopy (HREELS). The evidence was found in TPD measurements for structure sensitivity in decomposition of acetylene over the clean faceted Ir(210) surface versus the clean planar Ir(210) surface, which is attributed to nanometer sale structures on the faceted surface.