Metal-containing polymers (MCPs) are emerging as a class of interesting materials with promising properties and functions. Although many techniques are available for their synthesis, the range of main-chain MCPs available for material applications is limited. Most well-defined main-chain MCP syntheses rely only on the ring-opening polymerization (ROP) of metallocene monomers, thereby new synthetic approaches for novel MCPs are in high demand. In this study a new polymerization technique, migratory insertion polymerization (MIP), was explored and used to produce novel types of MCPs with asymmetric iron repeat-units connected by phosphine-iron (Ph2P-Fe) and iron-acyl (Fe-CO) bonds in the backbone. This research work involved the synthesis, characterization and polymerization of cyclopentadienyl(dicarbonyl)(diphenylphosphinopropyl)iron (FpP). FpP consists of an Fp functional group capable of undergoing a migratory insertion reaction (MIR) and a phosphine group to assist the MIR. FpP was prepared via the reaction between cyclopentadienyl dicarbonyl iron metalate (Fp anion) and (3-chloropropyl)diphenylphosphine, and was characterized using Fourier transform infrared (FTIR), 1H NMR, 31P NMR, 13C NMR, and ultraviolet-visible (UV-Vis) spectroscopies. The molecules undergo intramolecular cyclization reactions at low concentrations in organic solvents, while polymerization occurs in bulk at 70°C, leading to polymers with number-average molecular weights (Mn) up to 12,000 g/mol and narrow molecular weight distributions (PDI=1.08-1.33). These polymers are soluble in a wide range of organic solvents and have a Tg of 100°C.

<p>Development in the field of materials science is propagated by the synthesis of polynuclear metal-containing complexes, that exhibit enhanced chemical and physical properties. This thesis describes the synthesis of new metal-containing linear polymers and dendritic molecules.</p> <p>Chapter 1 presents an overview of the field of metal-containing polymers, with particular attention to the synthesis of polymers via condensation polymerisation. This review includes the various types of metal-containing condensation polymers and the applications of these materials, where available. This discussion is followed by a brief summary of metal-containing dendrimers, which includes a concise description of their structure and applications in general.</p> <p>There are two routes to preparing metal-containing polymers. Chapter 2 describes the synthesis of three bifunctional organometallic monomers, of the general type [M]-O-{2,6-(CH2OH)2-4-CH3-C6H2}, where [M] represents the various metal-containing moieties, (&eta / 5-C5H5)(CO)2 Fe(CH2)3 (25), (&eta / 5-C5H4-CH2CH2CH2-)Re(CO)3 (26) and Fpdendr (27). These monomers were prepared using 2,6-bis(hydroxymethyl)-p-cresol as the key reagent. The monomers were used in classical polycondensation reactions with terephthaloyl chloride using ambient temperature solution techniques. This yielded new low molecular weight oligomeric polyesters, that were characterised using FTIR and 1HNMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and sizeexclusion chromatography.</p> <p>In Chapter 3, an alternate route to metal-containing polymers is described. In this case, bifunctional organic monomers were polymerised to give preformed organic polymers. Two types of organic polymers were prepared, viz. polyesters (with pendant vinyl moieties) and polyimines (with &alpha / -diimine units along the polymer backbone). Functionalisation of these preformed organic polymers with various metal sources was attempted. Hydrozirconation reactions of the vinyl polyesters with Schwartz&rsquo / s reagent, Cp2Zr(H)Cl, were attempted and were largely unsuccessful. Competing reactions with the ester functionality prevailed, preventing the desired reaction. Reaction of the polyimines with PdCl2(COD) yielded insoluble, intractable metal-containing oligomers. Partial characterisation of the complexes is described.</p> <p>The synthesis of new poly(propylene imine) iminopyridyl metallodendrimers is described in Chapter 4. Schiff-base condensation reaction of the commercially available DAB dendrimers with 2-pyridinecarboxaldehyde, gave the dendrimers 51, 52, and 53, with four, eight and sixteen pyridylimine functionalities respectively on the periphery. Successful complexation reactions with PdCl2(COD), PtCl2(COD) and CuCl2 produced the corresponding metal-containing dendrimers, with either PdCl2 (54, 55, 56), PtCl2 (57) or CuCl2 (58) moieties bound on the periphery. The metallodendrimers were insoluble in the more common organic solvents, and were characterised by IR and 1H-NMR spectroscopy and microanalysis where possible. Dendrimers with salicylaldiminato ligands on the periphery were prepared by reacting the DAB dendrimers with salicylaldehyde. These ligands were reacted with various metal acetates in an attempt to prepare new metalcontaining salicylaldimine dendrimers. This work yielded either paramagnetic metal complexes or insoluble, intractable compounds.</p> <p>Chapter 5 describes the applications of the catalyst precursors (54, 55, 56, 57, 58), discussed in Chapter 4, in the polymerisation of ethylene and the use of complexes 54 and 55 as Heck cross-coupling catalyst precursors. The complexes all showed catalytic activity toward ethylene polymerisation. A discussion of their activity, the polyethylene molecular weight and microstructure is presented in this chapter. The precursors 54 and 55 are also effective catalysts in the Heck reactions, coupling iodobenzene with methyl acrylate, styrene and 1-octene in high conversions.</p> <p>General conclusions are given in Chapter 6.</p>

Metal-containing polymers (MCPs) are emerging as a class of interesting materials with promising properties and functions. Although many techniques are available for their synthesis, the range of main-chain MCPs available for material applications is limited. Most well-defined main-chain MCP syntheses rely only on the ring-opening polymerization (ROP) of metallocene monomers, thereby new synthetic approaches for novel MCPs are in high demand. In this study a new polymerization technique, migratory insertion polymerization (MIP), was explored and used to produce novel types of MCPs with asymmetric iron repeat-units connected by phosphine-iron (Ph2P-Fe) and iron-acyl (Fe-CO) bonds in the backbone. This research work involved the synthesis, characterization and polymerization of cyclopentadienyl(dicarbonyl)(diphenylphosphinopropyl)iron (FpP). FpP consists of an Fp functional group capable of undergoing a migratory insertion reaction (MIR) and a phosphine group to assist the MIR. FpP was prepared via the reaction between cyclopentadienyl dicarbonyl iron metalate (Fp anion) and (3-chloropropyl)diphenylphosphine, and was characterized using Fourier transform infrared (FTIR), 1H NMR, 31P NMR, 13C NMR, and ultraviolet-visible (UV-Vis) spectroscopies. The molecules undergo intramolecular cyclization reactions at low concentrations in organic solvents, while polymerization occurs in bulk at 70°C, leading to polymers with number-average molecular weights (Mn) up to 12,000 g/mol and narrow molecular weight distributions (PDI=1.08-1.33). These polymers are soluble in a wide range of organic solvents and have a Tg of 100°C.

<p>Development in the field of materials science is propagated by the synthesis of polynuclear metal-containing complexes, that exhibit enhanced chemical and physical properties. This thesis describes the synthesis of new metal-containing linear polymers and dendritic molecules.</p> <p>Chapter 1 presents an overview of the field of metal-containing polymers, with particular attention to the synthesis of polymers via condensation polymerisation. This review includes the various types of metal-containing condensation polymers and the applications of these materials, where available. This discussion is followed by a brief summary of metal-containing dendrimers, which includes a concise description of their structure and applications in general.</p> <p>There are two routes to preparing metal-containing polymers. Chapter 2 describes the synthesis of three bifunctional organometallic monomers, of the general type [M]-O-{2,6-(CH2OH)2-4-CH3-C6H2}, where [M] represents the various metal-containing moieties, (&eta / 5-C5H5)(CO)2 Fe(CH2)3 (25), (&eta / 5-C5H4-CH2CH2CH2-)Re(CO)3 (26) and Fpdendr (27). These monomers were prepared using 2,6-bis(hydroxymethyl)-p-cresol as the key reagent. The monomers were used in classical polycondensation reactions with terephthaloyl chloride using ambient temperature solution techniques. This yielded new low molecular weight oligomeric polyesters, that were characterised using FTIR and 1HNMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and sizeexclusion chromatography.</p> <p>In Chapter 3, an alternate route to metal-containing polymers is described. In this case, bifunctional organic monomers were polymerised to give preformed organic polymers. Two types of organic polymers were prepared, viz. polyesters (with pendant vinyl moieties) and polyimines (with &alpha / -diimine units along the polymer backbone). Functionalisation of these preformed organic polymers with various metal sources was attempted. Hydrozirconation reactions of the vinyl polyesters with Schwartz&rsquo / s reagent, Cp2Zr(H)Cl, were attempted and were largely unsuccessful. Competing reactions with the ester functionality prevailed, preventing the desired reaction. Reaction of the polyimines with PdCl2(COD) yielded insoluble, intractable metal-containing oligomers. Partial characterisation of the complexes is described.</p> <p>The synthesis of new poly(propylene imine) iminopyridyl metallodendrimers is described in Chapter 4. Schiff-base condensation reaction of the commercially available DAB dendrimers with 2-pyridinecarboxaldehyde, gave the dendrimers 51, 52, and 53, with four, eight and sixteen pyridylimine functionalities respectively on the periphery. Successful complexation reactions with PdCl2(COD), PtCl2(COD) and CuCl2 produced the corresponding metal-containing dendrimers, with either PdCl2 (54, 55, 56), PtCl2 (57) or CuCl2 (58) moieties bound on the periphery. The metallodendrimers were insoluble in the more common organic solvents, and were characterised by IR and 1H-NMR spectroscopy and microanalysis where possible. Dendrimers with salicylaldiminato ligands on the periphery were prepared by reacting the DAB dendrimers with salicylaldehyde. These ligands were reacted with various metal acetates in an attempt to prepare new metalcontaining salicylaldimine dendrimers. This work yielded either paramagnetic metal complexes or insoluble, intractable compounds.</p> <p>Chapter 5 describes the applications of the catalyst precursors (54, 55, 56, 57, 58), discussed in Chapter 4, in the polymerisation of ethylene and the use of complexes 54 and 55 as Heck cross-coupling catalyst precursors. The complexes all showed catalytic activity toward ethylene polymerisation. A discussion of their activity, the polyethylene molecular weight and microstructure is presented in this chapter. The precursors 54 and 55 are also effective catalysts in the Heck reactions, coupling iodobenzene with methyl acrylate, styrene and 1-octene in high conversions.</p> <p>General conclusions are given in Chapter 6.</p>

Philosophiae Doctor - PhD / metal-containing complexes, that exhibit enhanced chemical and physical properties. This thesis describes the synthesis of new metal-containing linear polymers and dendritic molecules. Chapter 1 presents an overview of the field of metal-containing polymers, with particular attention to the synthesis of polymers via condensation polymerisation. This review includes the various types of metal-containing condensation polymers and the applications of these materials, where available. This discussion is followed by a brief summary of metal-containing dendrimers, which includes a concise description of their structure and applications in general. There are two routes to preparing metal-containing polymers. Chapter 2 describes the synthesis of three bifunctional organometallic monomers, of the general type [M]-O-{2,6-(CH2OH)2-4-CH3-C6H2}, where [M] represents the various metal-containing moieties, (η5-C5H5)(CO)2 Fe(CH2)3 (25), (η5-C5H4-CH2CH2CH2-)Re(CO)3 (26) and Fpdendr (27). These monomers were prepared using 2,6-bis(hydroxymethyl)-p-cresol as the key reagent. The monomers were used in classical polycondensation reactions with terephthaloyl chloride using ambient temperature solution techniques. This yielded new low molecular weight oligomeric polyesters, that were characterised using FTIR and 1HNMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and sizeexclusion chromatography. In Chapter 3, an alternate route to metal-containing polymers is described. In this case, bifunctional organic monomers were polymerised to give preformed organic polymers. Two types of organic polymers were prepared, viz. polyesters (with pendant vinyl moieties) and polyimines (with α-diimine units along the polymer backbone). Functionalisation of these preformed organic polymers with various metal sources was attempted. Hydrozirconation reactions of the vinyl polyesters with Schwartz’s reagent, Cp2Zr(H)Cl, were attempted and were largely unsuccessful. Competing reactions with the ester functionality prevailed, preventing the desired reaction. Reaction of the polyimines with PdCl2(COD) yielded insoluble, intractable metal-containing oligomers. Partial characterisation of the complexes is described. The synthesis of new poly(propylene imine) iminopyridyl metallodendrimers is described in Chapter 4. Schiff-base condensation reaction of the commercially available DAB dendrimers with 2-pyridinecarboxaldehyde, gave the dendrimers 51, 52, and 53, with four, eight and sixteen pyridylimine functionalities respectively on the periphery. Successful complexation reactions with PdCl2(COD), PtCl2(COD) and CuCl2 produced the corresponding metal-containing dendrimers, with either PdCl2 (54, 55, 56), PtCl2 (57) or CuCl2 (58) moieties bound on the periphery. The metallodendrimers were insoluble in the more common organic solvents, and were characterised by IR and 1H-NMR spectroscopy and microanalysis where possible. Dendrimers with salicylaldiminato ligands on the periphery were prepared by reacting the DAB dendrimers with salicylaldehyde. These ligands were reacted with various metal acetates in an attempt to prepare new metalcontaining salicylaldimine dendrimers. This work yielded either paramagnetic metal complexes or insoluble, intractable compounds. Chapter 5 describes the applications of the catalyst precursors (54, 55, 56, 57, 58), discussed in Chapter 4, in the polymerisation of ethylene and the use of complexes 54 and 55 as Heck cross-coupling catalyst precursors. The complexes all showed catalytic activity toward ethylene polymerisation. A discussion of their activity, the polyethylene molecular weight and microstructure is presented in this chapter. The precursors 54 and 55 are also effective catalysts in the Heck reactions, coupling iodobenzene with methyl acrylate, styrene and 1-octene in high conversions. / South Africa