Bis(amidinate) dichloride complexes of the type M(L)2Cl2 (M=Zr, 2a; M=Ti, 2b; L=CyNC(C5H5FeC5H4)NCy) were synthesized by treating 2 equiv of ferrocenyl amidine, H(L), with M(NMe2)2Cl2 (M=Ti, Zr.2THF). Half sandwich mono(amidinate) complexes, Cp’ZrLCl2 (Cp’=Cp, 2c; Cp’=Cp*, 2d), were prepared by the reaction of Cp’ZrCl3 with 1 equiv of Li(L). The dialkyl complexes, M(L)2Me2 (M=Zr, 3a; M=Ti, 3b), CpZr(L)(CH2Ph)2 (3c) and Cp*Zr(L)Me2 (3d) were prepared by treatment of the dichloride complexes (2a-2d) with an appropriate alkylating agent. The dichloride complexes (2a-2d) activated with MAO, and dialkyl complexes (3a-3d) activated with B(C6F5)3 and [Ph3C][B(C6F5)4] show low to moderate ethylene polymerization activities. Cyclic voltammetry studies on the metal complexes containing ferrocenyl amidinates reveals quasi reversible oxidation and reduction waves for the ferrocene/ferrocenium couple.

Bis(amidinate) dichloride complexes of the type M(L)2Cl2 (M=Zr, 2a; M=Ti, 2b; L=CyNC(C5H5FeC5H4)NCy) were synthesized by treating 2 equiv of ferrocenyl amidine, H(L), with M(NMe2)2Cl2 (M=Ti, Zr.2THF). Half sandwich mono(amidinate) complexes, Cp’ZrLCl2 (Cp’=Cp, 2c; Cp’=Cp*, 2d), were prepared by the reaction of Cp’ZrCl3 with 1 equiv of Li(L). The dialkyl complexes, M(L)2Me2 (M=Zr, 3a; M=Ti, 3b), CpZr(L)(CH2Ph)2 (3c) and Cp*Zr(L)Me2 (3d) were prepared by treatment of the dichloride complexes (2a-2d) with an appropriate alkylating agent. The dichloride complexes (2a-2d) activated with MAO, and dialkyl complexes (3a-3d) activated with B(C6F5)3 and [Ph3C][B(C6F5)4] show low to moderate ethylene polymerization activities. Cyclic voltammetry studies on the metal complexes containing ferrocenyl amidinates reveals quasi reversible oxidation and reduction waves for the ferrocene/ferrocenium couple.

The new ligand L1 [2-[(E)-2,6-diisopropylphenyl-phenyimino]-2H-acenaphthylen-(1E)-ylidene]-(2,4,6-trimethyl-phenyl)-amine was prepared by stepwise addition of 2,6-diisopropylaniline and 2,4,6 trimethylaniline to acenaphthenequinone. The L1NiBr2 complex crystallized as a pseudo tetrahedral monomer, as determined by single crystal X-ray diffraction. This new catalyst L1NiBr2 and 3 related catalysts, bis(2,6-diisopropylphenyl)acenaphthenediimineNiBr2 (L2NiBr2), [(N,N'-bis-(2,6-diisopropylphenyl)-phenanthrene-9,10-diylidendiamineNi-η3-C3H4COOCH3)]+.{B[C6H3(CF3)2]4-} [(L3Ni-η3-C3H4COOCH3)]+.{B[C6H3(CF3)2]4-} and N-(2,6-diisopropylphenyl)-N'-(2,4,6-trimethylphenyl)-phenanthrene-9,10-diylidenediamineNiBr2 (L4NiBr2) were tested for activity in ethylene polymerization. The super-bulky α-diimine nickel catalysts [(η3- L3NiC3H4COOCH3)]+.{B[C6H3(CF3)2]4-} and L4NiBr2 successfully produced higher molecular weight polyethylene with a high level of linearity compared to the less bulky α-diimine nickel catalysts (L1NiBr2 and L2NiBr2). The super bulky α-diimine backbone helped to compress the reaction space and therefore impede the ethylene insertion to active centre of the catalyst. For this reason, the catalyst activity for super- bulky backbone ligands (L3 and L4) is lower than for their analogous less-bulky backbone ligands (L1 and L2). In general, for both backbones, the nickel catalysts with all-isopropyl substituents produced higher molecular weight polyethylene with less linearity compared to the nickel catalysts with methyl substituents. Moreover, for the acenaphthene backbone, the nickel catalysts with all isopropyl substituents (L2NiBr2) got a higher activity compared to the nickel catalysts with methyl substituents (L1NiBr2). A similar catalyst activity trend was not observed for phenanthrene backboned catalysts. In contrast, L4NiBr2 showed a higher activity compared to [(η3- L3NiC3H4COOCH3)]+.{B[C6H3(CF3)2]4-} For all catalysts, the majority of branches, as characterized by 13C nuclear magnetic resonance, were methyl branches. Polymers with a high level of branches showed a sharp intensity in the loss modulus measured by dynamic mechanical analysis due to a high level of interfacial chains. A reduction in catalyst activity was observed with all nickel catalysts when supported on silica. However, supporting nickel catalysts helps to improve the linearity of the polymer. The same ligands L3 and L4 were used with palladium and successfully produced two new catalysts [L3PdCH3NCCH3]+.{B[C6H3(CF3)2]4-} and [L4PdCH3NCCH3]+.{B[C6H3(CF3)2]4-. Catalyst [L3PdCH3NCCH3]+.{B[C6H3(CF3)2]4-} was more active and produced higher molecular weight and less branched polymer than catalyst [L4PdCH3NCCH3]+.{B[C6H3(CF3)2]4-} in the polymerization of ethylene.

Thesis (doctoral)--Rijksuniversiteit te Utrecht, 1983. / Summary also in Dutch. Acknowledgements and vita in Dutch. Additional references inserted. Includes bibliographical references.

Despite the growing interest in heterogeneous polymerization catalysis, the majority of the polymerization catalysts used industrially are single-use entities that are left in the polymer product. Recoverable and recyclable polymerization catalysts have not reached the industrial utility of single-use catalysts because the catalyst and product separation have not become economical. The successful development of recyclable transition metal polymerization catalysts must take a rational design approach, hence academic and industrial researchers need to further expand the fundamental science and engineering of recyclable polymerization catalysis to gain an understanding of critical parameters that allow for the design of economically viable, recoverable solid polymerization catalysts. Unfortunately, the rapid development of Atom Transfer Radical Polymerization over the past 10 years has not resulted in its wide spread industrial practice. Numerous reports regarding the immobilization of transition metal ATRP catalysts, in attempts to increase its applicability, have extended the fundamentals of recyclable polymerization catalysis. However, for industrial viability, more research is required in the area of how the catalyst complex immobilization methodology and support structure affect the catalyst polymerization performance, regeneration, and recyclability. A comprehensive rational catalyst design approach of silica-immobilized ATRP catalyst was undertaken to answer these questions and are discussed here.

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