Browsing by Author "Meijboom, Reinout"

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    New iron bis(imino)pyridyl complexes containing dendritic wedges for alkene oligomerisation
    (2005) Overett,Matthew J; Meijboom, Reinout; Moss John R
    The synthesis, characterisation and catalytic behaviour of new iron bis(imino)pyridyl complexes containing dendritic wedges, as well as the synthesis of bis(para-hydroxyphenylimino)pyridines is described. The hydroxyl functionality of the bis(para-hydroxyphenylimino)pyridines was used to attach dendritic wedges of the carbosilane type as well as the benzylphenyl ether type. After attachment of the dendritic wedges, complexation of these ligands to iron(II) chloride was achieved. The resulting dendritically functionalised bis(imino)pyridyl iron complexes were tested in the catalytic oligomerisation of ethene.
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    The synthesis and chemistry of new carbosilane dendrimers and their use in polymerisation catalysis
    (2001) Meijboom, Reinout
    The immobilisation of homogeneous catalysts is an area of research that attracts a great dela of attention. The immobilisation of catalysts on organic polymers and on inorganic materisl such as silica is a well known strategy. Recently, dendrimers have also been used as support materials. In this thesis, an investigation towards the immobilisation of homogeneous polymerisation catalysts on dendrimers is described.
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    Synthesis, crystal structure and hydroformylation activity of triphenylphosphite modified cobalt catalysts
    (Royal Society of Chemistry, 2004) Haumann, Marco; Moss, John R; Meijboom, Reinout; Roodt, Andreas
    The dinuclear complex [Co2(CO)6{P(OPh)3}2] (2) has been synthesised and was fully characterised. The solid state structure revealed a trans diaxial geometry, no bridging carbonyls, and Co–Co and Co–P bond lengths of 2.6722(4) and 2.1224(4) Å, respectively. Catalysed hydroformylation of 1-pentene with 2 was attempted at temperatures in the range 120 to 210 °C and pressures between 34 and 80 bar. High pressure spectroscopy (HP-IR and HP-NMR) was used to detect hydride intermediates. High pressure infrared (HP-IR) studies revealed the formation of [HCo(CO)3P(OPh)3] (4) at ca. 110 °C, but at higher temperatures absorption bands corresponding to [HCo(CO)4] (3) were observed. The hydride intermediate 4 has also been synthesised and characterised. Upon increased ligand concentration, HP-IR studies showed the formation of new carbonyl absorption bands due to a higher substituted cobalt carbonyl complex-[HCo(CO)2{P(OPh)3}2] (5), which is believed to be catalytically less active. Complex 5 has been synthesised independently and was fully characterised. A low temperature crystal structural study of 5 revealed a trigonal bipyramidal structure with a trans H–Co–CO arrangement and two equatorial phosphite ligands, the Co–P bond lengths being 2.1093(8) and 2.1076(8) Å, respectively.