Today, few water-soluble organometallic compounds are known, and little research has been done in this area. Water-soluble organometallic complexes are of interest for two reactions. First, a water-soluble compound that could be developed as a catalyst eliminates the need for organic solvents and allows the catalyst to be easily recycled. Secondly, water-soluble compounds can be introduced into biological systems, and like the water-soluble complex cisplatin may show anticancer activity. The compound, [lr(COD)(PMe3)3]CI (COD = 1,5-cyclooctadiene, Me = methyl), was synthesized and found to be water-soluble and fairly air-stable. Other water-soluble compounds, [lr(COD)(tripod)]CI, [lr(COD)(dmpe)]CI and [lrH(COD)(PMe3)3]CI2 [tripod = 1 ,1, 1-tris(diphenylphosphinomethyl)ethane, dmpe = (dimethylphosphino)ethane] were also synthesized by similar methods. All of the water-soluble compounds prepared were characterized by nmr and/or x-ray crystallography. [lr(COD)(PMe3)3]CI was found to undergo intramolecular rearrangement in solution and have a square pyramidal structure, which is unique for five-coordinate organometallic compounds. lr(COD) (tripod)]CI was also fluxional in solution, but it had the trigonal bipyramidal structure, usually observed in five-coordinate compounds. Several of the compounds synthesized were submitted to the National Cancer Institute for anticancer screening. Test results showed that the compounds exhibited some anticancer activity, but were non-selective towards a specific type of cancer. Nucleophilic addition reactions between [lr(COD)(PMe3)31CI and several nucleophiles were also studied. / Master of Science

1. The reactions of monochlormethyl ether with the magnesium cadmium and zinc derivatives of normal propyl and isopropyl halides were investigated. 2. In both the normal propyl and iso-propyl aeries, the yields of the expected condensation products RCH₂OCH₃ appeared in the order RMgX>R₂Zn>R₂Cd. 3. The primary organometallic compounds reacted with monochlormethyl ether in higher yields than did the corresponding secondary compounds. 4. A new method was developed for preparing a zinc-copper couple by heating a mixture of zinc dust and powdered cupric citrate under an atmosphere of nitrogen. 5. This method gave a couple superior in laboratory use to the zinc-copper couples how generally employed. / Master of Science

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Charles G. Riordan, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: This study comprises the preparation and characterization of various novel organometallic complexes of palladium(ll) which contain symmetric and unsymmetric (heteroatom-containing) r..-dicarbonyl-type ligands, T]3-heteroallyl ligands and T]3-coordinated trimethylsilyl-containing ligands. With the ultimate objective of preparing potential catalytic precursors similar to known catalytic precursors which exhibit hemilabile activity, the main goals of this study were the following: - • Investigate the coordination mode of the aforementioned ligand-types to the palladium of the starting compound, trans-[Pd(CeHs)CI{P(CeHshhl (1), by physical measurements. • Carry out single crystal structure determinations where possible. • Investigate the influence of the properties of the ligands on the stability of the prepared complexes. • Investigate the existence of hemilability (if any) in the prepared complex. The deprotonated symmetric and unsymmetric f!,-dicarbonyl-type ligands readily bind to the palladium of the starting compound in a bidentate fashion through the oxygens by displacing a triphenylphosphine group and producing easily removable sodium chloride. These complexes show that a negative charge can be accommodated in a delocalized fashion by the -S=O and - P=O groups of these acac--type ligands in a similar manner to the carbonyl groups of acetylacetonate. However, no evidence of hemilabile activity was found in this series of complexes. In a similar fashion, the deprotonated T]3-heteroallyl ligands, L = [PhzPS£], [PhCOz-], [PhC{NSi(CH3hhl [(Ph)zP{NSi(CH3hh-], were linked to palladium in the same starting complex, in T]3-fashion by triphenylphosphine substitution. No evidence of hemilabilty was evident in this series of complexes, but when L = [PhzPSz-], an exchange of the coordinated triphenylphosphine group with the free triphenylphosphine group was observed in the reaction mixture. Finally, the preparation, isolation and spectroscopic characterization of several T\3-allyl paliadium(lI) complexes with ligands of the type R-TeCH2CH2CQQCH3, (R = isopropyl, t-butyl ,ethyl) were attempted with the compound bis-( T\3-allyl )-di-~ -iodo-dipalladium( II), [T\3 -( CH2CHCH2J2Pd212J, which had also now been crystallographically characterized. Chelate formation by TeAQ coordination seemed possible by halide precipitation with silver tetrafluoroborate. Unfortunately the resulting compounds were too unstable to be isolated in the pure form for characterization. / AFRIKAANSE OPSOMMING: Die studie behels die bereiding en karakterisering van verskeie nuwe palladium(lI) organometaalkomplekse met inbegrip van simmetriese en onsimmetriese (heteroatoom bevattende) ~-dikarboniel-tipe ligande, 113- heteroallielligande en 113_gekoordineerdetrimetielsiliel bevattende ligande. Met die beoogde einddoel die bereiding van potensiele katalitiese voorgangers soortgelyk aan bekende katalitiese voorgangers met hemilabiele aktiviteit, sluit die hoof mikpunte van die studie die volgende in: - • 'n Ondersoek na koordinasie-wyse van die bogenoemde ligand tipes aan die palladium van die uitgangstof, trans-[Pd(C6Hs)CI{P(C6Hshhl (1), met behulp van fisiese bepalings. • Enkel kristal struktuur bepalings waar moontlike. • 'n Ondersoek na die invloed van die einskappe van die ligande op die stabilitiet van die komplekse. • 'n Ondersoek na die bestaan van hemilabiele aktiwiteit (indien enige) in die voorbereide complekse. Die gedeprotoneerde simmetriese en onsimmetriese ~-dikarboniel-tipe ligande het geredelik, bidentaat deur middel van die suurstowwe gebind aan die palladium van die uitgangstof deur die verplasing van die trifenielfosfien group en die vorming van verweiderbare natriumchloried. Hierdie komplekse dui aan dat 'n negatiewe lading wei geakkommodeer kan word deur delokalisasie by die -S=O- en -P=O-groepe van hierdie acac"-tipe Iigande, soortgelyk aan die karbonielgroep van asetielasetonaat. Geen hemilabiliteit is waargeneem in hierdie reeks komplekse nie. Die gedeprotoneerde 113-heteroalliel Iigande, L = [Ph2PS£), [PhCO£), [PhC{NSi(CH3h}£), [(PhhP{NSi(CH3hhl is op 'n soortgelyke wyse 113- gekoppel aan palladium van dieselfde uitgangstof met trifenielfosfien verplasing. Geen hemilabiliteit is waargeneem in hierdie reeks komplekse nie, maar wanneer L = [Ph2PS£], is 'n uitruiling van 'n gekoordineerde trifenielfosfien met 'n vrye trifenielfosfien in die reaksiemengsel waargeneem. Die bereiding, isolasie en spektroskopiese karakterisering van Tj3-alliel paliadium(lI) komplekse met ligande van die tipe R-TeCH2CH2COOCH3, (R = isopropiel, t-butiel ,etiel) is gepoog met die uitgangstof bis-(Tj3-alliel)-di-ll-iododipaliadium( II), [Tj3-(CH2CHCH2hPd2b], wat volledig gekarakteriseer was. Chelaat-vorming deur TeAO-koordinasie het moonlik blyk te wees deur halied presipitasie met behulp van AgBF4. Die komplekse is baie onstabiel en is dit gevolglik nie moontlik am die komplekse suiwer te isoleer en te karakteriseer nie.

published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy

The electronic structure of a variety of metal-heteroatom multiply bonded complexes, including some active alkyne metathesis catalysts, have been investigated using He(I) and He(II) ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and Fenske-Hall molecular orbital calculations. Utilizing this electronic structure information, confirmation of the proposed mechanism for the alkyne metathesis reaction which involves formation of a metallacyclobutdienyl intermediate was ascertained. Also, the important relationships between metallatetrahedral and metallacyclobutadienyl complexes, both of which have been mentioned as possible intermediates in the alkyne metathesis reaction and for which examples have been prepared and isolated, are discussed in significant detail. In the final chapters the electronic structure of some corresponding metal-nitrogen triply bonded complexes are discussed as well as the results probing the charge distribution in metal-heteroatom multiply bonded systems as determined by the XPS experiment.

The electronic structure factors that control Si-H and Ge-H bond activation by transition metals are investigated by means of photoelectron spectroscopy. Molecular orbital calculations are also used to gain additional insight into the orbital interactions involved in bond activation. The complexes studied have the general molecular formula (η⁵-C₅R'₅)Mn(CO)(L)HER₃, where R' is H or CH₃, L is CO or PMe₃, E is Si or Ge and R is Ph or Cl. These compounds are interesting models for catalysts in industrial processes like hydrosilation. The compounds display different stages of interaction and "activation" of the E-H bonds with the metal. One purpose is to measure the degree of Mn, Si, H 3-center-2-electron bonding in these complexes. The three-center interaction can be tuned by changing the substituents on Si, methylating the cyclopentadienyl ring, changing the ligand environment around the metal and substituting Si with Ge. The degree of activation is measured by observing the shifts in the metal and ligand ionizations relative to starting materials and free ligand in the photoelectron spectrum. Changing the substituent on Si extensively changes the degree of activation. Photoelectron spectral studies on (η⁵-C₅H₅)Mn(CO)₂HSiPh₃ show this to be a Mn(I) system. Progressive methylation of the cyclopentadienyl ring increases the electron richness at the metal center with no substantial effect on the degree of activation. Substitution on the metal (PMe₃ for CO) is less able to control the electronic structure factors of activation than the substitution on the Si atom. The magnitude of Ge-H bond activation is found to be of the same order as the Si-H bond activation for analogous compounds as found by studying (η⁵-C₅H₅)Mn(CO)₂HGePh₃, (η⁵-CH₃C₅H₄)Mn(CO)₂HGePh₃ and (η⁵- C₅(CH₃)₅)Mn(CO)₂HGePh₃ complexes by photoelectron spectroscopy. The photoelectron spectra of CpFe(CO)₂SiCl₃ and CpFe(CO)₂SiMe₃ were measured to study the electron charge shift from the metal to the ligand in these complexes as compared to CpMn(CO)₂HSiR₃ complexes. The photoelectron spectroscopic studies include numerous perturbations of the ligand and metal center to observe the extent of bond interaction and remain one of the best techniques to detect activation products.

Supercritical fluid chromatography has recently been coupled to an ICPMS detector. The method has been shown to be suitable for the speciation and analysis of organometallic compounds at trace levels. This study has attempted to further the research initiated by other groups in this field by developing a new interface for coupling these two instruments. The new interface makes use of a modified join between the nebuliser and the torch in the ICP unit. The effect of the mobile phase on the plasma with time has been investigated and little spectral background interference has been observed. The chromatographic conditions were optimised using a flame ionisation detector and a series of tin, arsenic, iron, and mercury compounds were analysed using SFC-ICPMS. Mter focusing the ICP-MS on the element of interest, each compound was evaluated in terms of the change in peak intensity with change in concentration and the theoretical detection limits were compared to the practical detection limit. The restrictor temperature was determined using a rough calibration procedure with bench top experiments. The effect of the restrictor temperature on the peak intensity of each compound was then studied. All results were plotted and a theory for the observed trends and observations is proposed. The results obtained and the interface used have been compared to the results and interfaces of other groups and differences have been explained. Attempts to extract relevant compounds from topsoil using supercritical fluid extraction were made. Finally, sediment samples were collected from relevant points in Durban Bay and an attempt was made to extract these samples using supercritical fluid extraction. The extracted samples were analysed using SFC-ICPMS although little success was obtained. Reasons for the failure of this method on the real samples have been proposed. In the concluding section of this study SFC~ICPMS has been evaluated in terms of its future applicability and use as a viable analytical method. / Thesis (M.Sc.-)-University of Natal, Durban, 1994.

No description available.

The successful application of Tppts, and its derivatives, in biphasic transition metal-catalysed reactions opened up a new field of chemistry requiring a rational design of water-soluble ligands. The main objective of the research described in this dissertation was the preparation and the application of new water-soluble phosphine ligands. The ligands were prepared by the use of carbon nucleophiles and chlorophenylphosphine derivatives. The carbon nucleophiles included malonate derivates, which were subsequently reduced to the di-alcohols and were transformed into water-soluble phosphines by the reaction with 1,4-butanesultone. Secondary and tertiary malonate nucleophiles were used and the steric demands of compounds containing more than one malonate group were investigated. Various attempts to obtain water-soluble compounds from dimalonate phosphine oxides failed. TBDMS-protected aryl halides were also used as nucleophiles. One (or two) of these silyl ethers was reacted with chlorophenylphosphine derivatives and after deprotection with TBAF the compounds were made water-soluble by a reaction with 1,4-butanesultone. The hydrogenation of arylphosphine oxides to form cyclohexylphosphine oxide derivatives was also investigated. However, these cyclohexylphosphines were more easily obtained by the reaction between the previously mentioned carbon nucleophiles and chlorocyclohexylphosphine derivatives, which were freshly prepared. A series of cyclohexyl-containing water-soluble phosphines was prepared in this way. The oxygen sensitive nature of phosphines lead to two different approaches in the reaction route: the phosphines were either borane protected followed by a subsequent deprotection step, or the phosphines were allowed to oxidise and were reduced back to the free phosphine at a later stage. The efficiency of both approaches in the reaction routes was examined. The deprotection of phosphine-boranes was performed using various “new” deprotecting reagents and the borane-species and free phosphines were separated using water/organic extractions. The various extraction coefficients of the amine-borane complexes were determined. The newly prepared ligands were used in a variety of palladium-catalysed reactions as well as in the hydroformylation of 1-octene employing rhodium. The reactions were performed in both neat organic solvents as well as mixtures between water and DMF or toluene and the results were compared to the use of Tpp and Tppts. It was found that many of the new ligands afforded superior yields compared to those of Tpp and Tppts. In the last part of the study, various diphenylphosphinic amides were used as DoM-groups. Sec- and tert-BuLi were used together with a variety of electrophiles to facilitate ortho-substitution on either one or two rings on the amides. This was seen as a start of a new approach towards functionalised phosphine ligands. / Prof. D.B.G. Williams