This Thesis describes X-ray crystallographic investigations on twelve compounds. The first three are the products of the acid condensation of ortho-aminobenzaldehyde, OAB, the so-called TAAB salts, based on the tetra-anhydro tetramer of OAB. Although known since 1926, their structures have remained controversial. Of the three salts, TAABH2(X)2, investigated, that of X = picrate was found to be ordered, whilst those of X = HSO4 and BF4 were disordered. The structure of the TAABH2 cation is saddle-shaped and based on a fused heptacyclic framework. In all the three salts the anion appears to be doubly hydrogen bonded to the cation, through hydrogen donors NH and CH. The results enable a controversy in the literature regarding the structures of these compounds to be resolved. The self-condensation products of anthranilic acid, AA, also somewhat controversial in nature, have been investigated. The formation of a trimeric, and minor yields of a tetrameric derivative, is confirmed. The crystal structures of the tetramer and of two solvates of the trimer (CHCI3 and CH3CN.H2O) were determined. These two compounds, also, have a fused heptacyclic double saddle-shape overall structure. Their structures are compared with those of the TAAB salts. Related types of hydrogen bonding are surveyed, and the results found in this Thesis are put in a wider context. The structure of the copper complex Cu(TAABH2 ) of reduced TAAB derivative TAABH4, a 16-membered tetra-azamacrocycle has been investigated. It, too, has an overall saddle-shape, but this is considerably flatter than those of the TAAB salts and AA derivatives. Two metal complexes (CuII and Felll) of a 14-membered tribenzotetra-azamacrocycle were investigated. In the case of the iron compound. X-ray crystallography showed that an unexpected, novel oxygenation reaction of the ethylene bridge had taken place to give an a,B-diketo group. The purpose-made copper diketo-analogue was examined for comparative purposes. This derivative, in contrast to that based on TAABH4 , has an almost square planar co-ordination around the copper atom. A compound, thought to have been the free parent ligand of these metal complexes, was also investigated. The data set was poor, but it could be shown that the compound was acyclic, contained an extra ortho-phenylene diamine residue, and was probably hydrogen bonded. The crystal structures of two metal complexes based on Cull and Felll of two dibrominated Schiff bases were investigated. The dibrominated copper salen derivative is monomeric, in contrast to the unbrominated compound, which is dimeric. The Felll derivative, like the earlier-mentioned oxidised tetra-azamacrocyclic iron derivative, has a dimeric structure, with the iron atoms linked by a p(?)-oxo-bridge. The structures of the three copper and two iron derivatives are discussed and compared. Three themes emerge from the twelve structures described in this Thesis: (i) the structural importance of hydrogen bonding, (ii) the inadequacy of a single valence bond formulation to explain the observed X-ray crystallographic results, and the need to invoke resonance forms, mainly ortho-quinonoid, and (iii) the versatile role of nitrogen in organic and metal organic heterocyclic structures.

This Thesis describes the measurement and interpretation of diffuse optical scattering from concentrated colloidal dispersions. Novel measurement techniques using optical fibres are investigated. These are applied to monodisperse spherical latexes where the results are compared with theories of radiative transport, and also to plate-like Kaolinite particles where non-random particle orientation by shear flow is studied at small and large Reynolds number. For the spherical latex dispersions various fibre configurations are investigated, the results being compared with multiple scattering predictions of the inverse scattering length S. All configurations give values of S which show the theoretical particle size dependence, but the single fibre bundle gives S in good absolute agreement with that calculated from an accepted approximate solution to the radiative transport equation. Comparisons of S between the single fibre bundle and the conventional integrating sphere method show good agreement, but only after making large specular reflectance corrections in the latter case. Measurements made on latex volume fractions (v) up to 0.4 showed a maximum in S at about v = 0.2, Interpreted as non-random destructive interference between ordered particles. For the kaolilnite dispersions S is measured as a function of shear rate, volume fraction, particle size, pH and deflocculant concentration. Using the anomalous diffraction and Rayleigh-Gans light scattering approximations, calculations are given which support a mods of particle orientation expected below the critical Reynolds number from the particle hydrodynamics over a wide range of rotational Peclet number. The results for concentric cylinder flow above the critical Reynolds number are explicable in terms of Taylor vortices. The shear-induced changes in S in laminar flow are shown to be a useful practical measure of the state of flocculation of the dispersion.

A study of preparation methods for alpha-aminoalkanephosphonic, alpha-aminoalkanephosphonous and alpha-aminoalkanephosphinic acids has been made, based on the combined use of an aldehyde, an amino com pound, and a phosphorus reagent. Reported yields are frequently poor and the mechanisms of the reactions are unclear. The synthesis of alpha-aminoalkanephosphonic acids has been systematically examined. Propanal was used as a model carbonyl compound in reaction with various combinations of the following: 1) (PhO)3P, (PhO)2PH, (MeO)3P, (MeO)2PHO, (Et0)2PH0, PCI3, H3PO3. 2) H2NC02Et, H2NC02CH2Ph, H2NCH2Ph, H2NCHPh2, H2NCONH2 , H2NC0NHPh. NH3. The yields of various routes developed have ranged from 65% to 12%. The products have been fully characterised by melting point, elemental analysis, and nmr (1H,13C,31P) spectroscopy. Radiolabelled alpha-amino4 -[14C ]-propanophosphonic acid was prepared for toxicology studies. An interesting feature of this compound has been the formation of chemically identical crystalline products whose melting points differ by 10°C after repeated recrystallisation. The crystal structure of alpha-amino4-[14C]-propanephosphonic acid was determined in order to examine the possibility of different crystalline forms. 31P nmr spectroscopy studies of "one-pot" syntheses of the alpha-aminopropanephosphonic acid have shown that low yields may be due to the formation of several phosphorus-containing by-products and not merely from the problems of isolation. A range of a-aminoalkanephosphonous acids and their derivatives has been prepared and characterised by nmr (1H,13C, 31P) spectroscopy. These acids were also examined by FAB mass spectrometry and were found to give strong [M+H]+ ions. New derivatives of alpha-aminopropanephosphonic acid were prepared and characterised. Results of screening tests have been presented.

1-Aminoalkanephosphonic acids and their derivatives, have long been claimed to be compounds with a wide variety of application. Numerous examples exist where they have been described as: complex-forming agents with sequestrating properties, extractants, wetting agents, pharmaceutical preparations, ion exchangers, herbicides, compounds with plant growth regulatory activity; inhibitors of aminopeptidases; as structural units in peptide analogues, functioning as antibacterial agents, which inhibit bacterial cell wall biosynthesis; as structural units in peptidic phosphonylating agents that irreversibly inhibit a wide variety of serine proteases; as structural units in butyloxycarbonyl protected phosphonate esters that complex with alpha-lytic proteases; and as structural units in peptidyl phosphonate diphenyl 9 10 esters which powerfully inhibit the enzyme thrombin. ...

The involvement of chemically-reactive oxygen radical species (RORS) in the pathogenesis of inflammatory joint diseases has been well documented. Much of the toxicity produced by increased superoxide ion (O2.-) and hydrogen peroxide (H2O2) generation has been attributed to the production of the highly reactive hydroxyl radical (.OH) which is mediated by low-molecular-mass iron chelates such as iron-citrate complexes. The .OH radical is extremely reactive and proving its formation in vivo is very difficult. Hence, assays for the assessment of .OH radical activity in the inflamed rheumatoid joint have involved identification and/or quantification of ‘unnatural’ chemical species produced by the attack of OH radical on a range of endogenous or, alternatively, therapeutically-administered exogenous 'target' molecules. This study involves: (1) An investigation of the precise chemical nature of intermediates in and so called 'endproducts' of the process of lipid peroxidation. Second-derivative (2D) electronic absorption spectrophotometry has been applied to the analysis of isomeric conjugated hydroperoxydienes, hydroxydienes and ketodienes and also to thiobarbituric acidreactive material in synovial fluid (SF) obtained from patients with inflammatory joint diseases. (2) A method for determining the extent of RORS-dependent peroxidation of polyunsaturated fatty acids (PUFAs) has been further developed for application to biological samples. This technique involves the conversion of conjugated hydroperoxydienes and compounds derived therefrom, i.e. oxodiene and hydroxydienes, to strongly chromophoric conjugated triene and tetraene species. The chromophore(s) produced are measured by their absorbance in the ultra-violet or near ultra-violet regions of spectra using 2D spectrophotometry. (3) An evaluation of the chemical nature of non-transferrin-bound iron in inflammatory synovial fluid is investigated by high-resolution, high-field proton (1H) nuclear magnetic resonance (NMR) spectroscopy, combined with the use of powerful iron(III) chelators (desferrioxamine and nitrilotriacetate), and the iron(lII)-binding protein apotransferrin in order to 'speciate' catalytic, low-molecular-mass iron complexes present in inflammatory SF samples. (4) The application of high field proton NMR spectroscopy to evaluate the abilities of the antioxidant thiol drug N-acetylcysteine and exogenous cysteine to protect metabolites present in intact inflammatory SF samples against oxidative damage arising from reactive oxygen radical species generated via gamma-radiolysis (5.00 kGy) in the presence of atmospheric oxygen.

5-Acatylamino-l,2-benzoquinone 2-oxine [5-AcqoH] results from the direct nitrosation of 3-acatylaminophenol together with its isomer 3-acetylamino-l,4-benzoquinone 4-oxine [3-AcqoH]. The quinone oximic structure of the former has been indicated by i.r. and n.m.r. studies. In the case of 3-AcqoH this type of structure has been established by X-ray crystallography. Following a brief review of quinone oxinic complexes, a study of the synthesis, properties and structure of Cu(II), Ni(II), Co(III), and Mn(III) complexes of 5-AcqoH is presented. The complexes Ni(5-Acqo)2.nH2O (n = 2-6), Cu(5-Acqo)2, Co(5-Acqo)3, and Mn(5-Acqo)2, .H2O were prepared by the direct reaction of 5-AcqoH with the appropriate metal(II) chloride or by the nitrosation of 3-acetylaminophenol in the presence of the metal salt. Co(5-Acqo)3 was also prepared by the reaction of the ligand with Na3[Co(NO2)6]. The complex Na(Co(5-Acqo)2 (NO2)2 ], resulted from the nitrosation of Na3(Co(NO2)6] in the presence of 3-acetylaminophenol. Pyrolysis of Ni(5-Acqo)2.6H2O gave Ni(5-Acqo)2. The complexes Cu(5-Acqo)2 and Ni(5-Acqo)2.nH2O (n = 0, 2-6) reacted with pyridine and 2,2-dipyridyl to give adducts whereas the complexes of M(5-Acqo)3 (M = Co, Mn) showed no reaction with pyridine. Magnetochemical measurements, indicated that all complexes, [except Ni(5-Acqo)2], are magnetically dilute and hence monomeric. Ni(5-Acqo)2 complex has a subnormal magnetic moment due to association. The diamagnetism of Co(5-Acqo)3 and the low spin configuration of Mn(5-Acqo)3.H2O are indicative of the strong field character of the ligand. COSY, H- and C n.m.r. studies have shown that Co(5-Acqo)3 is a mixture of facial and meridial isomers. For all complexes i.r. studies indicate the involvement of the ring CO in bonding. Their electronic spectra show strong absorption in the u.v. region which tails into the visible but d - d transitions have been clearly Identified for Ni(5-Acqo)2.6H20 and Mn(5-Acqo)3 .H20. Reexamination of the reaction of several complexes of type M(Rqo)2 [M = Ni or Cu) with dimethyl acetylenedicarboxylate has confirmed the occurence of cycloaddition and the formation of oxazine. A metal-containing product, M(II)(butynedioate), and in some cases an additional organic product, l,4-benoxazin-2-one, have been isolated. Mechanistic appraisals for the 1,4-benoxazinone formation are presented and the structure of one has been elucidated by X-ray crystallography. The reaction of the new complex Cu(5-Acqo)2 with DMAD leads to analogous products. The reaction of the complexes M(l-nqo)2 [M = Cu, Ni) with methyl propiolate give the hydrated M(II)(propynoate)2 and oxazine.

It was at the turn of this century, within the area of co-ordination chemistry that the interdependence of structure and reactivity was first realised. The understanding of interactions between metal and ligand has become more complex progressing from simple unidentate to the more complicated multidentate systems and in some instances, ligand designs have imposed unusual co-ordination geometrics around metal atoms. Such offsets are particularly evident in macrocyclic ligands. Their intrinsic properties as ligands gives them the potential to behave as catalysts, semiconductors and sequestering agents for use in pollution control and hydrometallurgy. In addition, they have impinged on the biomedical field, where they have become likely candidates for therapeutic reagents required for the treatment of metal intoxication, or used as diagnostic agents in the form of radio-labelled macrocycle-conjugated antibodies for better tumor imaging while their specificity and efficacy prove excellent for enzyme modelling. In 1987, achievements in this expanding field culminated in the form of a Nobel prize, awarded to C. J. Pedersen, J. M. Lehn and D. J. Cram and marked the scientific world's recognition of the importance of macrocyclic chemistry. Having briefly outlined the wealth of research associated with macrocyclic ligands currently being undertaken, one aspect is of special interest to this work. The objective of this project has been to design new selective complexing agents for the toxic heavy metal ions cadmium(II), mercury(II) and lead(II). Resulting observations on the properties of such systems should provide a better insight of how and why certain ligands 'discriminate' or appear selectively to complex with only certain metal ions. In addition, the project supplements an ongoing study of related work which forms part of a series within a matrix of similar macrocyclic ligands.

A wide range of diphosphines and their complexes with chromium, molybdenum, and tungsten carbonyl moieties has been synthesised and characterised, arid studied by proton, C-13 and P-31 n.m.r. spectroscopy. In many cases the diphosphines have one or more centres of chirality, and this leads to the formation of diastereomers that are readily distinguishable by n.m.r. The P-31 chemical shifts occur in specific ranges that are often structurally diagnostic, and are interpreted in terms of 'group contributions’, 'coordination chemical shifts', and the effects of chelate 'ring strain’. In order to obtain values of geminal and vicinal P-31 to proton coupling constants which can be used to assess conformational details, recourse was had to C-13/H -1 two-dimensional heteronuclear chemical shift correlation experiments. These use effective chemical shifts introduced by the presence of a single C -13 nucleus to reduce the extent of second-order character in the spectrum and hence give values of N(PC) and N(PH) together with their relative signs. Synthetic studies have also been undertaken on the triphosphine ligand (Ph2P)2CHCH2PPhH, which has a chiral phosphorus atom, and its complexes. When all three phosphorus atoms are coordinated to the same metal atom this leads to considerable ring strain, but nonetheless such complexes are stable, but show interesting variations in their n.m.r. properties. The presence of the P-H bond in this triphosphine and its complexes permits base-catalysed addition reactions with species such as (Ph2P2)2C=CH2 to yield derivatives of the pentaphoshine [(Ph2P)2CHCH2]2PPh in a regio- and even stereo-selective manner. This behaviour has been studied, and several new complexes have been prepared and their n.m.r. properties have been determined.

The aims of this project fall into two main categories. The primary objective was the preparation and characterisation of novel [alpha]-aminophosphonic acids and their phosphonate ester derivatives. Compounds of these types are of interest because of their potential for biological activity, particularly in the area of agricultural chemistry. The second objective was to investigate the conformation of selected examples of these types of molecules in solution. This was achieved by considering the proton-proton and proton-phosphorus coupling constants. These coupling constants were obtained by the full analysis of the 1H NMR spectra. The strategy adopted for the preparation of the phosphonic acids started from the synthesis of imine precursors. The imines were prepared by condensing aminodiphenylmethane or [alpha]-methylbenzylamine with a wide variety of aldehydes and ketones, using very mild reaction conditions. The imine precursors were then reacted with diethyl (or dimethyl) phosphite to give diethyl (or dimethyl) 1-substituted-l-(diphenylmethylamino)methanephosphonates, which were isolated and characterised. The phosphonate esters prepared from the reactions of imines derived from [alpha]-methylbenzylamine were not isolated. A series of the phosphonate esters [diethyl 1-phenyl-l-(diphenylmethylamino)methanephosphonate, diethyl l-(l’-naphthyl)-l-(diphenylmethylamino)methanephosphonate and diethyl l-(1’-pyrenyl)-l-(diphenylmethylamino)methanephosphonate] were selected for full 1H NMR spectral analysis. The effects of the aromatic ring currents exerted by the extended aromatic substituents were investigated. The complex aromatic regions of the 1H NMR spectra were not analysed. The X-ray crystal structures of selected diethyl 1-substituted-1- (diphenylmethylamino)methanephosphonates, where the substituents are: phenyl, 1’-naphthyl, 9'-anthryl, I'-pyrenyl, 2'-pyrrolyl and piperonyl, were determined and are discussed. The phosphonate esters were subjected to acid-hydrolysis to yield the [alpha]-aminophosphonic acids, including l-N-phenylethylamino-l-(2'-thienyl)phosphonic acid which was prepared from the imine derived from [alpha]-methylbenzylamine. Full 1H NMR spectral analysis was carried out on [alpha]-aminopropanephosphonic acid at three different pH values. The results of these analyses are discussed and compared with the results of the NMR spectral analysis of [alpha]-aminopropanephosphinic acid.

X-ray crystallographic analyses of a group of salicylaldoxime ligands, and their copper(II) complexes were carried out. The three of the copper(II) complexes studied, bis-(2-hydroxy-5-methylbenzaldehydeoximato)copper(II), [(L1)2Cu]n, bis-(2-hydroxy-5-methylbenzophenoneoximato)copper(II), [(L5 )2Cu] and bis-(2-hydroxy-3-t-butyl-methylbenzaldehydeoximato)copper(II), [(L7 )2Cu], existed as centrosymmetric molecules, with the copper atom at crystallographic inversion centre. Two bidentate ligands produce a planar arrangement of donor atoms around the copper. The molecules reassemble macrocyclic systems, due to effective intramolecular hydrogen bonding linking the two ligands. To correlate chelating properties with intramolecular H-bond strengths an X-ray structural analysis was carried out on one ligand supplied by ICI, and thought to be 3,5-dimethyl-2-hydroxy acetophenone methoxyimine. Unexpectedly the molecule was found to be 3,5-dimethyl-4-hydroxy acetophenone methoxyimine. This was successful in explaining the anomolously low efficiency of extraction for copper(ll), shown by the related n-nonyl oxime ligand. It is thought that the presence of syn and anti isomers in 2-hydroxybenzophenone oximes accounts for the low efficiency of copper extraction shown by reagents which contain this chelating unit. The syn and anti forms, of 2-hydroxy-5-methylbenzophenone oxime (L5H) were prepared separately. Significantly both forms appear to yield [L5]2CH] when treated with Cu(CH3CO2)2.H20 in a homogeneous solution, although there are indications that formation of the complex from the syn-form is slower. Selectivity of complexation of metal ions by macrocyclic ligands were investigated. The stability constant data of zinc(II) and cadmium(II) complexes of a series of cyclic quadridentate ligands were compared. For the 15-membered N4 macrocyle L15, the propyl (L15p) and butyl (L15b) C-alkylated derivatives were synthesised for the first time, and the cadmium(II) complex of (L15b) was prepared. X-ray analysis were performed on the free ligand L15b, and the three metal complexes [Zn(L15)(NO3)(H2O)]NO3, [Cd(15)(NO3)NO3, and [Cd(L15b)(NO3)NO3. These results were then correlated with the results of stability constant measurements in discussing the probable behaviour of the ligands in the solution environment and hence to provide some insight into the effect of alkylation on the discrimination for zinc(II) over cadmium(II). The discrimation for zinc over cadmium is decreased on alkylation and the reason for this is discussed.