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Batch catalytic and high pressure infra-red studies of catalytic systems have provided detailed information about the homogeneous rhodium-chloride catalysed hydrocarbonylation of ethene to form propanoic acid in CH(_3)COOH/c.HC1 at 180ºC and 60 bar pressure. [Rh(CO)(_2)Cl(_2)]- was shown to be an active catalyst for this process. Tin(ll) chloride as a co-catalyst was shown to have an effect on the rate of propanoic acid production for a rhodium-chloride catalytic process, but a clear promotional effect was only observed for systems employing a Sn:Rh molar ratio of 2: 1. Sn:Rh molar ratios higher than 2: 1 lead to a decrease in the selectivity for propanoic acid, while those lower than 2:1 result in catalytic activity consistent with [Rh(CO)(_2)Cl(_2)]- being an active species. The reactions of rhodium(I) carbonyl chlorides with tin(II) chlorides were carried out at atmospheric pressure to investigate the reaction chemistry between species present in the catalytic process. [Rh(CO)(_2)Cl(_2)]- and Rh(_2)(CO)(_4)Cl(_2) react with SnCl(_2) and SnCl(_3)- in both THF and CH(_2)Cl(_2) to form Rh(I)-CO-SnCl(_3) complexes. Infra-red and (^119)Sn NMR data identified the 5-coordinate complex [Rh(CO)(_2)(SnCl(_3)) (_3)](^2-)- as the favoured species formed in solution. Its crystal structure is reported. However, it appears to be related by a series of facile reactions, involving dissociation of SnCl(_3)(^-)- and CO groups, to several other 4 and 5-coordinate Rh(I)-CO-SnCl(-3) complexes. [Rh(CO)(SnCl(_3))(_4)](^3-), [Rh(CO)(SnCl(_3))(_2)Cl](^2-), and [Rh(CO)(_2)(SnCl(_3))X](^-) (X = Cl(^-) or SnCl(_3)(^-)) have been isolated from solution, often as mixtures along with [Rh(CO)(_2)(SnCl(_3))(_3)](^2-). Spectroscopic and X-ray crystallographic data indicated that SnCl(_3)(^-)- is a significant π- tacceptor ligand, thus explaining its ability to form 5-coordinate 18-electron rhodium(I) complexes. The effect of tin(II) chloride on the rhodium-chloride catalytic reaction is attributed to changes in π-acceptor and trans effect properties when SnC1(_3)(^-)- replaces chloride ligand(s). High pressure infra-red studies are consistent with both [Rh(CO)(_2)Cl(_2)](^-) and a Rh(I)CO- SnCl(_3) complex being catalytically active in a rhodium-tin-chloride system, and the carbonyl absorptions observed are consistent with [Rh(CO)(SnCl(_3))(_4)](^3-), [Rh(C0h(SnC(_3))(_3)](^2-) and [Rh(CO)(SnCl(_3))(_2)Cl](^2-) as catalytic precursors. The general predominance of [Rh(CO)(_2)(SnC1(_3))(_3)](^2-) in solution at atmospheric pressure and room temperature, suggests that it may be the favoured catalytic precursor, undergoing conversion to a catalytically active 16-electron Rh(I)-SnC1(_3) complex such as [Rh(CO)(_2)(SnCl(_3))X]- (X = Cl(^-) SnCl(_3)(^-)) via dissociation of SnCl(_3)-.

KB-1 is an anaerobic Dehalococcoides-containing microbial culture used industrially to bioremediate sites impacted with chlorinated solvents. The culture is typically grown at pH 7. However, lower pH is often encountered and therefore the effect of pH was investigated. Both sudden and stepwise decreases in pH from 7 to 6 and 5.5 were investigated over a period of 450 days. An electron balance was also calculated to look at the flow of electrons for dechlorination. More than 95% of the reducing equivalents went towards methanogenesis and acetogenesis. Select microorganisms were compared by quantitative Polymerase Chain Reaction. It was found that lower rates of dechlorination correspond to low Dehalococcoides numbers and that different methanogens were enriched on different electron donors.

KB-1 is an anaerobic Dehalococcoides-containing microbial culture used industrially to bioremediate sites impacted with chlorinated solvents. The culture is typically grown at pH 7. However, lower pH is often encountered and therefore the effect of pH was investigated. Both sudden and stepwise decreases in pH from 7 to 6 and 5.5 were investigated over a period of 450 days. An electron balance was also calculated to look at the flow of electrons for dechlorination. More than 95% of the reducing equivalents went towards methanogenesis and acetogenesis. Select microorganisms were compared by quantitative Polymerase Chain Reaction. It was found that lower rates of dechlorination correspond to low Dehalococcoides numbers and that different methanogens were enriched on different electron donors.

Twelve porphyrin dyads linked by an ethene bridge were synthesised as model systems for conjugated polymers. The extent of interporphyrin interaction was investigated for meso-meso and meso-β linked homo- and heterobimetallo-porphyrin dyads. To complement these dyads, model monomers with alkenyl substituents were also studied. Once the synthesis of these compounds was achieved, the extent of interaction was studied using UV-visible and fluorescence spectroscopy and molecular modelling. In order to gain a true indication of the extent of interaction in a dyad, the effect of the bridge as a substituent must be accounted for. This was achieved by studying the series of monomers by UV-visible and fluorescence spectroscopy. The increased conjugation resulting from mono- and bis-alkenyl substituents results in a red shift of the origin of transition energies in the absorption spectrum which is accompanied by a broadened and less intense Soret band and an increase in the intensity of the Q bands. The emission of these compounds also displays an increase in Stokes shift and a loss of vibronic coupling due to the increased conjugation. The serendipitous synthesis of three asymmetric meso-β ethene-linked porphyrin dyads was achieved by the use of palladium-catalysed Heck coupling of mesoethenyl- with meso-bromoporphyrins. A possible mechanism for this meso to β rearrangement was proposed. A series of nine meso-meso ethene-linked dyads was synthesised by palladium-catalysed Suzuki coupling of meso-(2-iodoethenyl)- with meso-borolanylporphyrins. All of these dyads were characterised by 1D and 2D NMR as well as MS analysis. The absorption spectra of ethene-linked dyads exhibit a split Soret band and a red-shifted and intensified HOMO-LUMO band. In the meso-β dyads, the degree of splitting in the Soret band is sufficient only to generate a shoulder on the red edge, whereas in the meso-meso dyads two separate bands appear. The extent of splitting is believed to be an indication of the amount of porphyrin-porphyrin interaction. The fluorescence profiles of the dyads change dramatically depending upon the central substituents in the porphyrins and the wavelength used for irradiation, which suggests that different conformations of these compounds give rise to different parts of their absorption and emission profiles. The fluorescence profiles of the dyads also do not reflect their absorption profiles, and therefore the excitation of the dyad is believed to be accompanied also by a change in geometry. All ethene-linked dyads exhibited an anti-Stokes shift, and the excitation spectra of the different parts of the fluorescence envelope also support the possibility of different conformers contributing to the fluorescence spectra. Molecular mechanics and time-dependent quantum mechanical calculations were performed on seven ethene-linked porphyrin dyads. These calculations further support the proposal of different conformations contributing to the physical properties of ethene-linked dyads. Electronic structure calculations also show considerable electron density on the alkene for the meso-meso ethene-linked dyads, which highlights the important influence of this bridge upon the electronic nature of these conjugated diporphyrins.

This diploma thesis is focused on study of polymerization of hexa-1,5-diene catalyzed by phenoxy-imine titanium dichloride (FI Ti) and methylaluminoxane (MAO) as cocatalyst. Effect of monomer concentration, polymerization temperature and cocatalyst/catalyst ratio on catalytic activity, molecular weights, polydispersities and particularly microstructure of prepared poly(hexa-1,5-diene) was studied. 1H NMR spectroscopy revealed that the poly(hexa-1,5-diene) microstructure contained methylene-1,3-cyclopentane (MCP) as well as vinyl tetramethylene (VTM) units. Kinetics of this polymerization was studied. Finally, copolymer of ethene and hexa-1,5-diene possessing incorporated pendant vinyl group was prepared.

The aim of the study will be the determination of the kinetic profiles of the polymerization of propene, ethene and their mixtures with commercial Ziegler-Natta catalyst by application of two different experimental procedures. The prepared polymer material will be utilized for the SEC analysis and subsequent evaluation of the concentration of active sites. The determined molecular mass distribution curves will be further investigated by the application of the procedure, which deconvolute the overall profile on the basic Flory's distribution functions. Then the comprehensive study about character and behavior of various types of active centers in dependence on time and type of monomer will result from this investigation.

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