A new methodology using simple acid-base hydrolysis of aminosilanes with molecules containing terminal hydroxyl groups, has been developed for the preparation of supports for heterogenized homogeneous catalysis. The flexibility of this approach has allowed the build-up of new materials ranging from simple organometallic thin films to complex organometallic-inorganic sol-gel networks, and organophosphine and metallodendrimers. The acid-base hydrolytic route to construct thin films containing phosphine and amine donor ligands on glass surfaces, eliminates the problems of the traditional surface functionalization techniques. Surface modification involves the reaction of SiCl4 with the surface hydroxyl groups of glass, quartz and single crystal silicon, followed by the addition of NEt2H, resulting in the formation of [Si]-NEt2 sites on the surface, which can undergo acid-base hydrolysis with phosphine and amine ligands containing terminal OH groups, to afford thin films of various long alkane chains containing terminal donor ligands. Bridge-splitting and ligand displacement reactions were used to anchor the organometallic complexes of Ni(0), Rh(I), Ru(II) and Pd(0). A detailed analysis of their characterization is reported. The catalytic efficiencies were examined for the cyclooligomerization of phenylacetylene using the thin film, [Si]-O-(CH 2)3PPh2Ni(CO)2PPh3, and the hydrogenation of diphenylacetylene with the long alkane chain thin film, [Si]-O-(CH2)nPPh2Rh(1,5-C8H 12)(Cl) (n = 10--12). Both anchored catalysts were highly active and selective, resulting in product distributions that differed from similar reactions with solution complexes. / In an attempt to prepare solution analogs to the surface-bound species, an interesting class of Rh(I) complexes of the type, Rh(CO)(Cl)(PPh3 )(NRR'R″) were synthesized, of which Rh(CO)(Cl)(PPh3)(HNEt2) and Rh(CO)(Cl)(PPh 3)(H2NCy) were crystallographically characterized. Reactivity of the complex, Rh(CO)(Cl)(PPh3)(HNEt2) towards haloalkanes was also explored, resulting in Rh(III) amine anionic complexes of the type, [RhX4(CO)(PPh3)]-(H2NEt 2)+. X-ray structural characterization of the Rh(III) complexes are discussed. The catalytic reactivity of Rh(CO)(Cl)(PPh3 )(HNEt2) in the hydrosilation of 1-hexene, shows higher activity than both Rh(CO)(Cl)(PPh3)2 and RhCl(PPh3) 3. In the presence of CCl4, Rh(CO)(Cl)(PPh3)(HNEt 2), was able to polymerize styrene and methyl methacrylate. / An alternative approach to sol-gel processing, based on acid-base hydrolysis, was used to develop organometallic network supports. The organometallic-inorganic sol-gel was prepared in an non-aqueous medium, under mild reaction conditions, using commercially available reagents, eliminating many of the problems related to the traditional sol-gel technique. The organometallic-inorganic hybrid network catalyzed tolan hydrogenation with selectivities for the fully hydrogenated product, bibenzyl. / In the final part of the study on supported catalysis, tri-branched organophosphine and metallo-dendrimers are prepared in excellent yields via acid-base hydrolytic chemistry. The organophosphine dendrimers are used to subsequently bind the Rh(I)(COD)(Cl) complex. An examination of the 31P NMR and MALDI data suggests dendrimer growth. The Rh(I) dendrimers were employed as catalysts for decene hydrogenation resulting in activities similar to the monomeric adduct.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35963 |
| Date | January 1998 |
| Creators | Petrucci, Maria G. L. |
| Contributors | Kakkar, Ashok K. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001655625, proquestno: NQ50297, Theses scanned by UMI/ProQuest. |
Page generated in 0.0017 seconds