A selection of metal complexes including ligands of the type R3Xn-3M (where X = halide, M = Sn, Pb, n = 0-3) were prepared and studied using multinuclear N.M.R. spectroscopy.

A series of dibenzo macrocyclic tetraamine ligands with 14-, 15-, 16-, 17- and 19-membered inner great lings (L14 to L15) has been synthesized to investigate the effect of ring size variation on their complexation behaviour with the metal-ions, Ni(Il), Zn(ll) and Cd(II).

3-Hydroxytetrahydrofuran, 3,4-epoxybutan-1-o1 and 3,4-epoxy-3- methylbutan-1-o1 were synthesized. The corresponding methacrylate esters were also prepared and their spectroscopic data are presented. The commercially available 3-methyloxetan-3- ylmethanol was converted to its methacryloyl ester and the analytical data was presented.

The use of oxo-transition metal complexes (particularly molybdenum and vanadium) as catalysts for a number of synthetically important reactions is described. The ability of alkyl hydroperoxides to epoxidise alkenes in the presence of transition metal catalysts is well known and is reviewed here along with the more conventional methods of preparing epoxides in the laboratory, with particular emphasis on their application in asymmetric epoxidations. In this work a number of novel oxo-vanadium and oxo-molybdenum complexes containing bulky and/or chiral ligand systems have been prepared and their application as potential catalysts for regio and/or asymmetric epoxidation has been studied. A synthesis of the oxo-vanadium complex of the known ligand NN''-ethylenebis(iminomethylCcunphof ) was developed and the complex characterised. The synthesis and structure of oxo-molybdenum complexes containing novel tridentate ligands derived from substituted salicylaldéhydes and chiral 2-aminoalcohols are also described along with a D(-)-2,3- butandiol complex of dioxomolybdeniam(VI ). As in a number of examples recently reported in the literature, epoxidation of geraniol and related compounds in the presence of these catalysts showed regioselectivity with exclusive reaction of the allylic double bond. The latter complex was also found to give low asymmetric induction in epoxidations of geraniol. In addition to using pre-formed chiral complexes as asymmetric epoxidation catalysts the possibility of using chiral catalysts prepared in situ from simple molybdenum complexes and an excess of the chiral ligand has also been studied. Some of these systems appeared to give the highest asymmetric inductions in epoxidations of geraniol. During the studies of the epoxidation reaction it was found that some of the oxo-vanadium and oxo-molybdenum complexes were very efficient catalysts for the isomerization of allylic alcohols. The scope of rearrangement reactions of this type was examined for ten structurally different allylic alcohols. It was shown that in most cases isomerization leads to an equilibrium mixture and in some cases the position of equilibria differ from that which would be predicted from classical considerations. Several attempts were also made to prepare more reactive isomerization catalysts by synthesising oxo-vanadium complexes with fluorine containing ligands.

Interaction of triphenylphosphine with Ni(XqO)2 (XqOH = 2-nitrosophenol, X = 4-chloro, 4-bromo, 4-methyl and 5-methoxy) resulted in deoxygenation to give mainly bis(2-triphenylphosphiniminophenolato) nickel(ll), Similarly the interaction of triphenyl phosphine with Zn(qO)2 (qOH = 5-methoxy-2- nitrosophenol) involved deoxygenation and formation of bis(2-triphenylphosphiniminophenolato)zinc(ll). Action of dilute hydrochloric acid on these complexes afforded the hydrochlorides of the corresponding N(2-hydroxybenzene)iminotriphenyl phosphoranes. The hydrochlorides on neutralisation with sodium carbonate gave, in most cases, the parent N(2-hydroxybenzene)- iminotriphenyl phosphorene.

X-ray analyses of fifteen carbonyl clusters of ruthenium and osmium have been completed which demonstrate several new aspects of cluster structure.

The reaction of 5-hydroxy-2-nitrosophenol (mnrH), 5-hydroxy-6-methyl-2-nitrosophenol (6-MemnrH). 2 4-dinitrosooresorcinol (dnrH2) and substituted dinitrosoresorcinols (X-dnrH2) with various metal salts gave monomeric, dimeric and polymeric metal complexes such as M(mnr)2 (M=Cu, Ni and Fe); Cu(OH)(mnr); M(dnr)(M=Ni or Cu). The complexes of type M(mnr)j , M(6-Memnr)2 and M(dnr) (M=Cu or Ni) form 1:2 adducts with pyridine. These complexes were investigated using spectroscopic, thermogravimetric and magnetochemical techniques, and where appropriate by Mossbauer spectroscopy. The complexing behaviour of 3-methyl-4-oxime-IH-pyrazol-4, 5-dione (poH) and 3-methyl-4-oxime-l-phenvl-lH-pyrazol-4,5-dione (PpoH) with nickel(II) and copper(II) has been reinvestigated. Three new iron(II) complexes derived from these ligands have been prepared either by the reaction of PpoH with iron(II) under aqueous conditions or by the reaction of poH with iron pentacarbonyl in anhydrous THF. The latter reaction also afforded a number of organic products, the formation of which has been rationalised in terms of nitrene intermediates. The complexes Fe(Ppo)2.H2O, Fe(Ppo)2 .2py and Fe(po)2.H2O were found to be high spin. This property contrasts the behaviour of iron(II) complexes derived from 2-nitrosophenols, which are low spin, and is rationalised in terms of conjugation effects and the bonding character of the pyrazol-4, 5-dione monooxime ligand. The interaction of Cu(mnr)2. 2py with triphenylphosphine gave several products including a phenoxazinone and a novel phenoxazinone phosphorus ylid whose structure was elucidated by X-ray crystallography. The complex Cu(6-Memnr)2. 2py behaved similarly towards triphenylphosphine. The synthetic significance of these reactions is discussed. Kinetic studies on the reaction between triphenylphosphine and Cu(mnr)2 .2py indicate that adduct formation takes place initially. It is suggested that subsequent deoxygenative decomposition of this adduct leads to the products. Attempts to clarify the proposed mechanism through the use of insoluble polymer supports were not fruitful.

A stirred flow reactor was adapted to study the rate of formation of hydrocarbons in the low pressure, 10mmHg, oxidation of propanal, n-butanal and iso-butanal over the temperature range 710-783K.

The synthesis of 1,2-naphthoquinone I-oxime and 1,2- naphthoquinone 2-oxina complexes of rhodium and Iridium has been Investigated. In the case of rhodium, complexes of the type Rh(l-nqo)3 have been prepared by reacting 1 ,2-naphthoquinone 1-oxime with hydrated rhodium(III) chloride. Both products ware obtained as mixtures of isomers. The Interaction of 1,2- naphthoquinone 2-oxime with rhodium(lll) chloride yielded Rh(2-nqo)3 also as a mixture of Isomers. The trichelates were also obtained from the nitrosation of the appropriate naphthol in the presence of rhodium(Ill) chloride. In contrast, the corresponding reaction systems involving iridium gave very complex mixtures Involving both iridium containing species and organic products. One of the iridium products, [pyH][lr(1-nqo)C13 pyl, has been isolated in the pure state and characterised by X-ray crystallography. The complexes Ir(1-nqo)3 and lr(2-nqo)3 were also isolated but in low yields. All trichelates ware shown to be diagmagnetic. None reacted with either pyridine or triphenylphosphine. These observations have been rationalised in terms of crystal field stabilisation energy. The behaviour of the rhodium and iridium complexes towards the Lewis bases contrasts that of analogous iron and cobalt complexes. The X-ray study of [pyH][lr(l-nqo)C13 py] has shown that the ligand is chelated to the metal as been observed in first transition series metal complexes derived from such ligands. The use of 1,2-naphthoqulnone 1-oxime as a potential ligand for separating rhodium from iridium has been investigated. Optimum conditions for recovery of rhodium was established, as a technique for refining rhodium current process at Inco (Europe) Ltd. The synthesis of cobalt, rhodium, copper, iron and nickel complexes of 1 ,2-naphthoquinone l-oxime-3,6- disulphonic acid (nRsH3) has been investigated and the complexes were isolated in solid form by developing a separation technique. Cobalt(III) and rhodium(III) salts reacted with the ligand to give metal complexes of type M(nRs Na)3 . The behaviour of the 1,2-naphthoquinone 1- oxime-3,6-disulphonic acid towards iron(ll) and iron(lll) or copper salts was shown to be more complex and interesting than previously reported. Both iron(II) and iron(III) chloride gave an Iron(II) product of the type Fe(nRs Na) whilst Iron(II) ammonium sulphate gave an Fe(II) product of the type Fe(nRs Na)2. The nickel salts gave a complex containing two ligands per metal, Ni(nRsHNa)2. The complexes of Iron(II) and copper(Il) of 1 ,2-naphthoquinone l-oxime-3,6-disulphonic acid catalysed aerobic oxidation of catechols. The oxidation involved oxidative cleavage of the aromatic ring of catechol by molecular oxygen to give muconic acid anhydride and 2H-pyran-2-one in addition to benzoquinone. This behaviour is very similar to enzyme catalysed oxygenation.

The development of an effective test system for detecting the irradiation status of foodstuffs is essential for the establishment of legislative control and consumer choice. For foodstuffs consisting mainly of water, treatment with ionising radiation initially generates highly reactive free radical species (hydroxyl radical (‘OH), hydrated electrons (e-aq) or hydrogen atoms (H)). These react extremely rapidly with a wide variety of “target" molecules in foodstuffs resulting in small but detectable chemical changes. Hence, assays for the assessment of ‘OH radical activity involve the identification and/or quantification of chemical species produced by the attack of ‘OH radical on a range of biomolecules occurring in foodstuffs. This study Involves an investigation of radiolytically-induced chemical modifications arising from the Interaction of ‘OH radical with naturally occurring aromatic compounds in fruits and vegetables. High performance liquid chromatography coupled with electrochemical detection has been applied to the analysis. In addition, the chemical nature of intermediates in, and end-products arising from the interaction of ‘0H radical with polyunsaturated fatty acids and carbohydrates Is reviewed by application of second-derivative (2D) electronic absorption spectrophotometry. The 2D spectrophotometric technique has not been previously applied to food studies and may serve as a potential “probe” for the measurement of radiolytic products generated as a consequence of irradiation treatment. Additionally, high-field, high-resolution proton nuclear magnetic resonance spectroscopy has been employed to assess radiolytically-induced damage to biomolecules present In shellfish.