Classical methods of analyzing heat capacity data for the characteristic moments of the frequency distribution are applied to iridium and rhodium. Impurity moments are determined from high and low temperature f values. These moments are combined by modern theory to estimate the magnitude of the host-host to host-impurity force constant ratio. Ratios of the various host moments are also examined.

<p> Reaction of the hydrated trichlorides of rhodium and Iridium with hexamethyldewarbenzene gave the complexes, (C5Me5MCl2)2 (M=Rh, Ir). A mechanism for this reaction is proposed.</p> <p> The dichloro complexes, (C5Me5MCl2)2, were reacted with a number of di- and tri-enes in ethanol in the presence of base and gave a variety of pentamethylcyclopentadienyl complexes of M(l) and M(lll). Evidence for a hydrido intermediate is presented and the hydrido- and deuterido- complexes, C5Me5IrH(D)ClPPh3, were isolated and characterised.</p> <p> The isomers endo-H and exo-H pentamethylcyclopentadiene(cyclopentadienyl) rhodium were isolated and showed significant differences in their properties. Cyclooctadienes reacted with (C5Me5MCl2)2 to give C5Me5M(1,5-C8H12) via the intermediacy of the π-2-cyclooctenyl complexes C5Me5MCl(C8H13); mechanisms are presented to account for the observed products. Cyclohexadienes gave the complexes, C5Me5M(1,3-C6H8). 1,4-Cyclohexadiene was isomerised to 1,3-C6H8; the rhodium complex, C5Me5Rh(1,3-C6H8), was a very active catalyst for the disproportionation of 1,3-C6H8 to cyclohexene and benzene, both ethanol and base were cocatalysts.</p> <p> Mass spectral data for these and other organo-metallic complexes are presented.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

The reaction between 2 acetamino 6 amino benzo thiazole and chloroiridio acid is not sensitive enough to be of importance as a colorimetric quantitative reaction. IrCl₆-- can be detected with this organic compound if iridium is present in as much as 0.02 mg. per ml. of solution providing ferric iron is absent. If ruthenium is present it must be removed before the test for the iridium anion can be made. / M.S.

The oxidative addition of H-H to iridium(l) trimethylphosphine complexes was studied and the reactivity of the resulting water soluble dihydrido iridium (III) complexes was investigated. One Dihydrido iridium(III) complex, mer-Ir(H)₂(PMe₃)₃CI <b>(2)</b> was characterized by ¹H, ³¹p and ¹³C NMR spectroscopy, CH analysis and single crystal xray diffraction. <b>(2)</b> reacted with the strong sigma donor PMe₃ to form [IrH2(PMe₃)4]CI <b>(3b)</b> without having to remove the chloride ligand. <b>(2)</b> reacted with monosubstituted acetylenes and an internal diyne in water to form the vinyl complexes Ir(H)(C(R')=C(H)-(R))(PMe₃)₃CI (R = CMe₃, C₆H₅, SiMe₃, R' = H, <b>(4)-(6);</b> R' = CCMe₃, R= Me, <b>(7)). (2)</b> also reacted in water with ethynylpyridine to form an unusual metallacycle "trimer" <b>(8)</b>. A mechanism for tltrimerizationtl is proposed. <b>(2)</b> also reacted with ethylene in water to form the diethyl iridium complex Ir(CH₂CH₃)₂(PMe₃)₃CI <b>(8)</b>. Encouraged by these results, catalytic hydrogenation of unsaturates in water was investigated. It was found that <b>(2)</b> is active as a water soluble catalyst for hydrogenation of unsaturates. A mechanism for catalytic hydrogenation was proposed. / Ph. D.

The present work describes the design and synthesis of a series of dimers [(η5 - ring)MCl]2(μ2 -Cl)2, (where (η5 -ring)MCl = (η5 -Me4C5R)Rh(III)Cl or (η5 -Me4C5R)Ir(III)Cl). Iridium and rhodium dimeric complexes were synthesized via a microwave reaction and directly compared through single-crystal X-ray crystallography. Finally, the dimeric complexes were evaluated as potential oxidation catalysts. The modified HCp*R (R = isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, nheptyl, n-octyl, phenyl, benzyl, phenethyl, cyclohexyl, and cyclopentyl) type ligands were synthesized by reaction of 2,3,4,5-tetramethylcyclopent-2-en-1-one with the respective Grignard reagent (RMgX), followed by elimination of water under acidic conditions to produce the tetramethyl(alkyl or aryl)cyclopentadienes in moderate to excellent yields (39 - 98%). Reaction of the HCp*R ligands with [M(COD)](μ2 -Cl)2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) gave the dimeric complexes [Cp*RMCl]2(μ2 -Cl)2 in yields ranging from 16 - 96%. The dimers were characterized by nuclear magnetic resonance (NMR)spectroscopy, single-crystal X-ray diffraction (XRD) (supplemented by powder XRD), high-resolution mass spectrometry (HRMS), and elemental analysis. Complexes studied by XRD were analyzed to understand the bond lengths and bond angles throughout each complex. The dimeric complexes synthesized, will facilitate a complete study on how the R group influences catalytic activity. / Master of Science

Yes / A series of ruthenium and iridium complexes have been synthesized and characterized with 20 novel crystal structures discussed. The library of β-ketoiminato complexes has been shown to be active against MCF-7 (human breast carcinoma), HT-29 (human colon carcinoma), A2780 (human ovarian carcinoma), and A2780cis (cisplatin-resistant human ovarian carcinoma) cell lines, with selected complexes’ being more than three times as active as cisplatin against the A2780cis cell line. Selected complexes were also tested against the noncancerous ARPE-19 (retinal pigment epithelial cells) cell line, in order to evaluate the complexes selectivity for cancer cells. Complexes have also been shown to be highly active under hypoxic conditions, with the activities of some complexes increasing with a decrease in O2 concentration. The enzyme thioredoxin reductase is overexpressed in cancer cells, and complexes reported herein have the advantage of inhibiting this enzyme, with IC50 values measured in the nanomolar range. The anticancer activity of these complexes was further investigated to determine whether activity is due to effects on cellular growth or cell survival. The complexes were found to induce significant levels of cancer cell death by apoptosis with levels induced correlating closely with activity in chemosensitivity studies. As a possible cause of cell death, the ability of the complexes to induce damage to cellular DNA was also assessed. The complexes failed to induce double-strand DNA breaks or DNA cross-linking but induced significant levels of single-strand DNA breaks, indicating a mechanism of action different from that of cisplatin. / Lord RM, Hebden AJ, Pask CM, Henderson IR, Allison SJ, Shepherd SL, Phillips RM, McGowan PC

Yes / Platinum complexes are the most widely used anticancer drugs; however, new generations of agents are needed. The organoiridium(III) complex [(η5-Cpxbiph)Ir(phpy)(Cl)] (1-Cl), which contains π-bonded biphenyltetramethylcyclopentadienyl (Cpxbiph) and C^N-chelated phenylpyridine (phpy) ligands, undergoes rapid hydrolysis of the chlorido ligand. In contrast, the pyridine complex [(η5-Cpxbiph)Ir(phpy)(py)]+ (1-py) aquates slowly, and is more potent (in nanomolar amounts) than both 1-Cl and cisplatin towards a wide range of cancer cells. The pyridine ligand protects 1-py from rapid reaction with intracellular glutathione. The high potency of 1-py correlates with its ability to increase substantially the level of reactive oxygen species (ROS) in cancer cells. The unprecedented ability of these iridium complexes to generate H2O2 by catalytic hydride transfer from the coenzyme NADH to oxygen is demonstrated. Such organoiridium complexes are promising as a new generation of anticancer drugs for effective oxidant therapy. / We thank the ERC (247450), SNSF (PA00P2_145308 for N.P.E.B.), IAS (for I.R.C.), BBSRC (for J.M.H.), Science City (AWM and ERDF), and the EPSRC for support, and Prof. Timothy Bugg and members of EC COST Action CM1105 for stimulating discussions. We also thank Professor Pat Unwin, Mike Snowden, and Rob Lazenby for their help with the electrochemical experiments and the National Cancer Institute for NCI-60 human tumor cell panel screening.

Yes / The fabrication of precious metal (ruthenium, osmium, gold, and iridium) nanocrystals from single atoms has been studied in real-time. The dynamics of the first stage of the metal nanocrystallisation on a doped (B,S)-graphitic surface are identified, captured, and reported. / We thank the Leverhulme Trust (Early Career Fellowship No. ECF-2013-414 to NPEB), the ERC (Grant No. 247450 to PJS), EPSRC (EP/F034210/1 to PJS).

Hydrogen terminated silicon surfaces play an important role in the integrated circuit (IC) industry. Ultra-pure water is extensively used for the cleaning and surface preparation of silicon surfaces. This work studies the effects of ultra-pure water on hydrogen passivated silicon surfaces in a short time frame of 120 minutes using fourier transform infrared spectroscopy – attenuated total reflection techniques. Varying conditions of ultra-pure water are used. This includes dissolved oxygen poor media after nitrogen bubbling and equilibration under nitrogen atmosphere, as well as metal contaminated solutions. Both microscopically rough and ideal monohydride terminated surfaces are examined. Hydrogen terminated silicon is also used as the sensing electrode for a potentiometric sensor for ultra-trace amounts of metal contaminants. Previous studies show the use of this potentiometric electrode sensor in hydrofluoric acid solution. This work is able to shows sensor function in ultra-pure water media without the need for further addition of hydrofluoric acid. This is considered a boon for the sensor due to the hazardous nature of hydrofluoric acid. Thin carbon films can be formed by spin coating photoresist onto silicon substrates and pyrolyzing at 1000 degrees C under reducing conditions. This work also shows that the electroless deposition of palladium and platinum may be accomplished in hydrofluoric acid solutions to attain palladium and platinum nanoparticles on a this film carbon surface for use as an electrode. Catalysis of these substrates is studied using hydrogen evolution in acidic media, cyclic voltammetry, and catalysis of formaldehyde. X-ray diffractometry (XRD) is used to ensure that there is little strain on palladium and platinum particles. Iridium is thought to be a prime candidate for investigation as a new generation copper diffusion barrier for the IC industry. Copper electrodeposition on iridium is studied to address the potential of iridium as a copper diffusion barrier. Copper electrodeposition is studied using a current-transient technique to obtain insight into the nucleation and growth mechanism. Copper on iridum was annealed up to 600 degrees C. X-ray photoelectron spectroscopy and XRD confirm that electrodeposited copper exists in a metallic state. XRD shows that copper exists in the characteristic face-centered cubic (111) form. XRD also confirms the stability of the copper-iridium interface with no new peaks after annealing, which is indicative that no interaction occurs. Scanning electron microscopy, and Scotch ® Tape peel tests confirm the uniformity and strength of copper on iridium even after annealing to 600 degrees C.