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Sugar chlorosulphates of furanoid and pyranoid derivatives bearing chlorosulphonyloxy groups at primary and secondary positions, were synthesized and examined mainly with a view to determine their extent of reactivity in terms of nucleophilic substitution reactions, especially with azide. Inversion of configuration occurred at reactive chiral centres, whereas intermediate azidosulphonyloxy derivatives (azidosulphates) were formed via S-Cℓ bond fission of the chlorosulphonyloxy group at less reactive primary or secondary centres, e.g. 1,2:3,4-diO̲isopropyl idene-α-D-galactopyranose 6-azidosulphate, 1,2-O̲isopropylidenea- D-xylofuranose 3-azidosulphate and 1,2:5,6-di-O̲-isopropyl idene-α-Dglucofuranose 3-azidosulphate. 1,2:3,4-Di-O̲-isopropylidene-α-Dgalactopyranose 6-azidosulphate ultimately afforded the 6-azidodeoxy derivative probably by an SN2 mechanism. Some SNi characteristics were,however, evident when substitution occurred at a reactive primary centre (e.g. methyl 2,3,4-tri-O̲-methyla- D-glucopyranoside 6-chlorosulphate), as the 6-azidodeoxy derivative obtained, appeared to be contaminated with a trace amount of the corresponding 6-chlorodeoxy sugar, which had presumably formed via an internal SNi mechanism, while no intermediate azidosulphonyloxy derivative was isolated. In another study, the reaction pathways for the synthesis of benzylated chlorodeoxy sugars having potential biological properties as exemplified by the multivalent drug, tribenoside, were also investigated

The reactions between the lanthanide nitrate salts and the ligand triphenylphosphine oxide (TPPO) gave rise to nine-coordinated complexes of the nature Ln(TPPO)3(NO3)3, for Ln = La – Dy, Er, Tm, in which the Ln(III) centre is coordinated to three phosphoryl oxygen atoms and three bidentate nitrate ligands. Generally, the geometry can be described as being mer-octahedral, where the nitrate ligands are considered as monoatomic species. The product of the reaction between Yb(NO3)3·5H2O and TPPO, however, was a highly symmetrical eight-coordinated complex, in which the Yb(III) centre was coordinated to two bidentate nitrate groups and four TPPO molecules. The geometry in this case is best described as being trans-octahedral, with the two nitrate ligands coordinated practically perpendicular to one another. The complexes isolated from the reactions of lanthanide nitrate salts with the ligand bis(pentamethylene)urea (PMU) had the general formula Ln(PMU)3(NO3)3, where Ln = La – Dy, Yb, Lu. The complexes were found to be nine-coordinated with distorted trigonal prismatic geometry, in which the one base of the prism is composed of the oxygen atoms of the three PMU ligands and the other base is made up by one oxygen atom from each of the bidentate nitrate groups. The second oxygen atoms of each of the nitrate groups protrude upward, occupying capping positions. The reactions of the La and Pr nitrate salts with the ligand 2,2’-dipyridyl-N,N’-dioxide (DPDO) produced two novel complexes of the nature [Ln(DPDO)(H2O)2(NO3)3]. These complexes are remarkable in that their crystal structures reveal the Ln(III) centres to be ten-coordinated. The geometry around the Ln(III) centres was complex, due to the presence of a seven-membered chelate ring, formed by the bidentate coordination of the oxygen atoms from the DPDO ligands to the metal centres. The chelate ring did not lie in a single plane, but was twisted at the pyridyl bridgeheads to lie above and below the coordination plane.

The compounds in the series from triphenylphosphine to triphenylbismuthine were examined as acceptors in oxygen transfer reactions involving the l-pyrroline-l-oxides. Triphenylphosphine was found to offer a useful route from the l-pyrroline-l-oxides to the corresponding pyrrolines. The second part of this work is centred on the structural investigation of Sanno's base (XV) (l), obtained as a by-product in the reductive cyclization of ethyl 2-acetyl-2-ethyl-4-methyl-3-nitromethyl valerate (aγ -nitro-ketone) and formulated by the author as having the Δ’ -pyrroline structure; this compound has since been found to be a cyclic nitrone (XVI). In the case of this complex nitrone, the oxygen transfer reaction to triphenylphosphine has been successful, yielding two isomeric Δ' -pyrrolines. The isolation of a Δ -pyrroline structure is confirmation of the proposed cyclic nitrone (XVI) structure for Sanno's base and as this provides a practical application of this reaction in structural work as well as showing that triphenylphosphine will reduce N-oxides in the presence of an ester group. / Science, Faculty of / Chemistry, Department of / Graduate

The amount of reaction between pyrite and vapor state nitric acid-has been analytically determined at 130°, 145°, 160° and 175° C. for one hour reaction time, and for one-half, one and two hour reaction times at 160°C. The variation of pressure with time for constant-boiling (68.2 per cent) nitric acid was studied at 130° and 160°C The reaction observed between pyrite and vapor state nitric acid followed the possible chain of reactions given below: (formula omitted) with the possible reaction: Fe₂(S0₄)₃ + H₂S0₄⇄Fe₂(S0₄)₃ . H₂SO₄. At 160°C the overall reaction was found to be of an apparent zero-order as was also that for the formation of ferric sulfate and ferric oxide, over the range of almost 100 per cent decomposition of the nitric acid. The maximum amount of pyrite used was about 11 per cent. Experimental results show that reactions (3), (4),(5) and (6) must all be surface reactions. A decrease in the rates of the reactions was noted between 145° and 160°C. This was most probably caused by the change in the physical and chemical properties of sulfur in this range, and indicates that elemental sulfur has a significant retarding effect on the rate of the overall reaction / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Final state interactions in the p-p and p-n systems corresponding to the formation of the singlet states of the di-proton and the deuteron have been observed in the reactions He³(He³,2p)He⁴ and T(He³,np)He⁴, by measuring the energy spectra of two of the final state particles detected in coincidence. These interactions appear as regions of high density of events along the kinematic contours in two dimensional energy space. Both p-p and p-He⁴ coincidences from the reaction He³(He³,2p)He⁴ and p-He⁴ coincidences from the reaction T(He³,np)He⁴ were studied. The dominant mechanism producing the three particle final states was found to be the sequential breakup through the states of Li⁵ and He⁵, in agreement with the results of previous experiments. The interaction between the two nucleons affects the distribution of coincidence events only in the region of two dimensional energy space corresponding to a breakup in which the two nucleons emerge with low relative energy. The relative contributions of the different processes in the reaction He³(He³,2p)He⁴ was determined for incident He³ energies from 1.15 MeV to 5.0 MeV. It was found that the nucleon-nucleon interaction becomes less important as the incident energy increases. The validity of two approximate theories of final state interactions, the Watson theory and the Phillips, Griffy and Biedenharn density of states formalism, was checked by comparing their predictions with the observed energy spectra. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

An accurately colliraated monenergetic fast neutron beam of small angular width was produced by bombarding a deuterium target with 2 MeV deuterons. Background reduction was achieved by using the associated particle technique and extensive shielding. Dual parameter pulse height analysis was used to reduce the coincidence time resolution between the detected neutrons and the associated He³ recoil particle to 4.6 nanoseconds by taking into account the variations in flight times of the He³ particles. A rotating thin film deuterated polyethylene target was developed which enabled a substantial increase in the neutron flux to be made. The beam of 70 neutrons/second/millisteradian produced, was of sufficient intensity to perform a small angle scattering experiment. The technique was tested by a measurement of the angular distribution from 40 degrees to 10 degrees of neutrons elastically scattered from lead. / Science, Faculty of / Physics and Astronomy, Department of / Graduate