I. Attempted synthesis and characterisation of an electron-deficient transition metal complex potentially useful in carbon-hydrogen bond activation. II. Investigations of mesoporous niobium oxide - cobaltocene composites: The first example of superparamagnetism in molecule-based clusters.

Abstract

The attempted syntheses of electron deficient transition metal complexes proposed to be useful in C--H bond activation processes are reported. Because tris(trimethylsilyl)methane (HTsi) is sterically demanding but only donates one electron, we were interested in synthesising transition metal complexes with this ligand, under the assumption that these traits would be important in designing an extremely electron deficient transition metal complex for use in C--H bond activation processes. By means of three synthetic approaches, nucleophilic attack, oxidative addition and free radical reactions, the syntheses of several ligand complexes, Ir(Tsi)I(CO)(PPh3) 2, Rh(Tsi)I(CO)(PPh3)2, RhSiTsi(PPh3) 3, Ir(SiTsi)CO(PPh3)2, MnSiTsiCl, NbCl4Tsi, TaCl4Tsi, ZrCl3Tsi and TaMe3ClTsi) were attempted but most products were intractable. The isolation and characterisation via 1H NMR spectroscopy of a Ru--H species, (RuClH(C6H 5Tsi)PPh3), formed from the direct reaction of RuCl(Tsi)(C 6H6)PPh3 with LiTsi, is discussed. The characterisation of, and hypothesised mechanistic pathway towards a novel organic material, benzyl-Tsi, formed during the course of our investigations, is also reported. Source: Masters Abstracts International, Volume: 40-03, page: 0708. Adviser: David Antonelli. Thesis (M.Sc.)--University of Windsor (Canada), 2001