An approach to the synthesis of 2,6-diaryl-8-oxo-3,7-dioxabicyclo [3,3,0] octane lignan lactones is presented and then used in the synthesis of the natural products aptosimon and styraxin. The structure of aptosimon has now been confirmed as having a 2,6-diaryl structure rather than the 2,4-diaryl structure which has been postulated in the literature. A germination inhibitor MEL, isolated from Aegilops ovata, has also been synthesised. A key ring closing reaction in this strategy was a Lewis acid catalysed directed aldol reaction between a silyl enol ether and an acetal. A review of similar ring closures in the literature is presented. The use of alpha-arylidene lactones as intermediates in lignin synthesis has also been investigated. The stereochemistry of products from reactions used in this strategy was determined and as a result it was possible to successfully design a stereochemically controlled synthesis of dihydrosesamin.

This thesis describes the synthesis and reactivity studies of new arene-ruthenium(II) and arene-ruthenium(O) complexes. Ultrasound has been investigated as an alternative energy source, with the overall aim of synthesising arene ruthenium clusters. Chapter 1 gives an introduction and summary of the known arene ruthenium chemistry reported to date. Chapter 2 reports the synthesis of (CGH6)Ru(C2H4)2 and (MeC6H4CHMe2)Ru(C2H4)2. Low temperature protonation studies generated (C6H6)Ru(H)(CZH4)2' and (MeC6H4CHMe2)Ru(H)(C2H4)7ý. These are observed by 1H nmr spectroscopy to undergo two dynamic processes, rotation of the ethylene ligands and an exchange between the hydride and the hydrogens of the ethylenes. On protonation with trifluoroacetic acid (C6H6)Ru(02CCF3)2 has been shown to be the final product. Nucleophilic substitution investigations of the bis(ethylene) complexes has determined that the arene is more labile than the coordinated ethylene. Chapter 3 reports the generation of a reactive intermediate, [(MeC6H4CHMez)Ru(THF)2]", and the reactions it undergoes. The synthesis and stereochemistry of the new complexes [(MeC6H4CHMe2)RuBr(C3H5)] and Ru(H)[(C6H40) (OPh)2][P(OPh)3]3 are reported. Chapter 4 describes the successful synthesis of the project goal, with the formation of the trimer [(MeC. H., CHMe2)3Ru3Se,_1` and the tetra nuclear species [(MeC6H4CHMe2)4Ru4H4]2'. Electrochemistry shows both complexes undergo two, one-electron reversible reductions to generate their neutral analogues. Ru3(CO)12 was formed when arene ruthenium carbonyl clusters were sought. Chapter 5 reports the formation and reactivity of arene ruthenium complexes containing nitrogen based ligands. The half sandwich complexes, (arene)RuCl2(NH2R) (arene = C6H6, R= Et, CMe, C6H4Me; McC6H4CHMe2, R=CMe3) and (C. H6)RuCl(NHZCGH4Me)Z' have been synthesised in good yield. However, these complexes are not synthetically useful as substrates for cluster synthesis, although (C6H6)RuC12(NH2CMe3) can be converted to the mixed ethoxide-halide dimer, [(C6H6)Ru(OEt)]2Cl`. Me3SiN3 on reaction with [(MeC6H4CHMe2)RuC12]2 affords [(MeC6H4CHMe2)RuCl(N3)]Z. An X-ray crystal structure determination of this complex showed the nitrogens bridging the two ruthenium atoms are pyramidal rather than the expected planar in geometry. [(MeC6H4CHMe2)RuCl(N3)]2 undergoes chloride loss to form the triply bridged dimer, [(MeCGH4CHMe2)RuCl(N3)z]', and bridge cleavage to form [(MeC, H4CHMe2)RuCl(N3)PPh3]. The latter complex is believed to undergo disproportionation in solution. Conclusions and future directions of the project are discussed in chapter. 6. The appendix provides a discussion of ultrasound proposed structure.

The thesis describes synthetic studies towards the marine natural product phorboxazole A. This unprecedented compound was recently isolated from an Indian Ocean sponge and displays extraordinary levels of cytostatic activity against a broad range of human cancer cell lines. The Introduction summarises a variety of different natural products which have been targeted as anti-cancer agents, and compares their mode of action with that of phorboxazole A. A review of structurally related natural products is then included, followed by an account of how phorboxazole A was isolated and its structure determined. The Introduction concludes with a brief discussion on our planned retrosynthetic analysis and contemporaneous studies within our research group towards phorboxazole A. The Results and Discussion section of the thesis contains details of our synthetic studies towards two of the key fragments present from our retrosynthetic analysis, namely the oxazole bis-pyran unit and the side chain. A detailed discussion is presented throughout this section including a review of the hetero Diels-Alder reaction and methods of oxazole formation. This section culminates with a successful synthesis of the entire side chain of phorboxazole A. The third chapter of the thesis is the Experimental section containing full details of the preparative work completed and listing spectroscopic and analytical data for all new compounds synthesised during the study. The thesis is concluded by a schematic account of the contemporaneous total synthesis of phorboxazole A by the Forsyth research group at the University of Minnesota.

The main focus of this thesis is the investigation of structure and motion of different materials by applying different solid-state NMR techniques. In the first section (1) some of the bases of NMR are described both in a Classical (1.1) and Quantum Mechanical (1.2) approach, while the next two sections deal with the experimental part of the work. In section 2 solid-state NMR studies of CsC60 are described and an unambiguous assignment of the 13C NMR spectrum of the polymer phase of CsC60, which is based solely on our experimental data, is presented. In contrast to previous work, the assignment does not rely on the knowledge of the electronic structure of this material and our results support a fully three-dimensional electronic structure as opposed to a quasi one-dimensional one. This is achieved using a two-dimensional 13C MAS NMR correlation experiment, which identifies nuclei coupled via a through-bond scalar interaction, the Refocused INADEQUATE. In section 3 solid-state NMR experiments performed on polyethylene and long-chain n-alkanes corresponding to the formula C246H494 are described. Particular attention is given to some specific issues such as chain folding and a detailed study of the saturation-recovery curves (T1) obtained is carried out for different materials. The model elaborated is able to simulate all the data recorded and the presence of an interphase between the crystalline and the amorphous parts of the samples is proposed. To help the understanding of the structure and the motion of long-chain n-alkanes in section 3 some deuterated samples such as C216H434-d24 and C12H25(CH2)192CHDC11D23+C162H326 ("the mixture") are also studied. Deuterium NMR is widely used and we fit all the experimental line shape of the different samples at different temperatures. Diverse models for the structure and motion of such materials are given, which take into account all the experimental results obtained.

The reactions of amino- and formylimidazoles, and aminopyrimidinones are described. Conditions were found for the successful condensation of 5(4)-aminoimidazole-4(5)-carboxamide with a number of substituted benzaldehydes, to provide a series of novel 5(4)-N-benzylideneaminoimidazole-4(5)-carboxamides. Reaction of a subset of the benzylidene derivatives with sodium hydride furnished novel imidazo[1,5-a]quinazoline-3-carbox-amides in good yields, via an intramolecular cyclisation. Attempted mixed acid nitration of imidazo[1,5-a]quinazoline-3-carboxamide led only to amide hydrolysis to provide the carboxylic acid. High yielding conditions were sought for the synthesis of a formylimidazole by the selective partial reduction of commercially available 4,5-disubstituted imidazoles. Lithium triethoxy-aluminium hydride reduction of 1-benzyl-4,5-dicyanoimidazole gave a mixture of the isomeric monoaldehydes in a yield of 53%. Methyl 5(4)-formylimidazole-4(5)-carboxylate was formed by acidic hydrolysis of methyl 5(4)-diethoxymethylimidazole-4(5)-carboxylate. Unfortunately, Knoevenagel condensation of the formyl-imidazoles prepared with ethyl nitroacetate could not be achieved. Ethoxycarbonylacetylferrocene and 1,1'-bis(ethoxycarbonylacetyl) ferrocene, prepared from ferrocene in one and two steps respectively via Friedel-Crafts acylations, were heated with guanidine carbonate to provide 1-(2-amino-3,4-dihydro-4-oxopyrimidin-6-yl)ferrocene and 1,1'-bis(2-amino- 3,4-dihydro-4-oxopyrimidin-6-yl)ferrocene in low yields, though the latter appeared to decompose on storage. In studies aimed at preparing a pyrimido[5,4-b]indole, attempted nitrosation of 2-amino-6-phenylpyrimidin- 4-one with nitrosonium tetrafluoroborate gave the unexpected unsymmetrical dimer 2-amino -5-(3,4-dihydro-4-oxo-6-phenylpyrimidin-2-yl)-6-phenylpyrimidin-4-one, in low yield. To overcome the observed poor reactivity of 2- amino-5-halopyrimidin-4-ones towards Suzuki coupling with boronic acids, 2-amino-5-halo-4-methoxy-6-phenylpyrimidines were prepared and successfully coupled with a range of aryl and heteroaryl boronic acids to provide 5-aryl-and 5-heteroarylpyrimidines in good to excellent yields. As expected, the iodopyrimidine was more reactive to the palladium catalysed coupling than the bromo analogue. Acidic hydrolysis of the 5-arylpyrimidines furnished 2- amino-5-aryl-6-phenylpyrimidin-4-ones in excellent yields. Heck reactions of 2-amino-5-iodo-6-phenylpyrimidin-4-one and 1-hexyne gave only a low yield of 6-amino-2-butyl-4-phenylfuro[2,3-d]pyrimidine, involving intramolecular cyclisation. Unlike the trend observed for Suzuki reactions, Heck reaction of 2-amino-5-iodo-4-methoxy-6-phenylpyrimidine with 1-hexyne gave the coupled product, 2-amino-5-(1-hexyn-1-yl)-4-methoxy-6-phenylpyrimidine, but only in a low yield of 27%.

The thesis describes synthetic studies directed towards the total synthesis of 14,15-anhydrovirginiamycin M2, a streptogramin antibiotic of the virginiamycin family. This novel natural product shows pronounced antibacterial activity against a wide range of potentially lethal bacteria. The Introduction summarises the main therapeutic uses, isolation, structural determination, biosynthesis, and mode of action of the virginiamycins. Also included is a review of synthetic approaches which have been described to access these and similar streptogramin antibiotics by other research groups. A review of the intramolecular Stille coupling reaction within organic synthesis incorporating the most prominent examples of its use over the past ten years in the synthesis of natural products is also presented. The Discussion part of the thesis contains details of our synthetic studies on suitable model systems, including: a study of conjugated triene formation via Stille chemistry; peptidic bond formation; and special reference to the problems involved in the synthesis of the 2,4-disubstituted oxazole contained within the virginiamycins. The studies culminate with a description of the first total synthesis of 14,15- anhydrovirginiamycin M2, which proved identical to the natural product obtained from a Streptomyces fermentation process. A full description of the experimental work carried out, and spectroscopic data for all compounds synthesised, is contained in an Experimental section.

In chapter one, the various methods of generating benzenoid orthoquinodimethanes are discussed and approaches to their heterocyclic analogues are also reviewed. The utility of ortho-quinodimethanes in organic synthesis is highlighted by examples of both inter- and intramolecular Diels-Alder cycloadditions as the key steps in the total synthesis of naturally occurring polycyclic systems. In chapter two, work aimed at the development of a rapid synthetic entry to heterocyclic quinodimethanes starting from ortho-methyl heterocyclic carboxylic acids is presented. To this end, the dianion of 3-methylbenzofuran-2-carboxylic acid (018) was used to facilitate the construction of a "benzylsilane type" precursor (038) which in turn when treated with fluoride base, resulted in the generation of benzofuran-2,3-quinodimethane (012). We were then successful in trapping this intermediate with reactive dienophiles to form a series of the corresponding tetrahydrodibenzofurans (042 to 049). We have been able, for the first time, to determine the regioselectivity in this reaction by performing an X-ray crystallographic analysis on the major isomer (046) arising from cyclization with methylvinylketone. Preliminary work on an intramolecular variant as well as other heterocyclic acids is also presented. Chapter three, deals with the extensive modern approaches to tetrahydrofurans, but concentrates on examples that exhibit 2,5-disubstitution. It is sub-divided into the methods which involve an electrophile induced cyclization and the numerous alternative ones which do not. Their relevance in Natural Product assembly, especially the polyether antibiotics, is appraised. Chapter four continues with studies which have already established that Z-3-silyloxy-5-alkenoic acids undergo efficient and highly stereoselective iodolactonizations leading to the Mevinic analogues and related valerolactones. We have now established that the iodolactonizations of Z- and E-3-silyloxy-5-alkenoic acids (174 and 131) both lead to trans-disubstituted valerolactones, which differ only in the stereochemistry of the iodine substituent (175 and 178). The possibilities of effecting etherifications of the related Z-3-hydroxy-5- alkenoates (106) are then examined. By simply blocking the carboxylate end of the hydroxy-5-alkenoic acids involved in the above reactions it was found that under iodolactonization conditions a novel iodoetherification-hydroxylation process ensues which leads to 3-hydroxy-2,5-disubstituted tetrahydrofurans of which (182) is an example. These products were essentially single diastereoisomers according to all their spectroscopic data indicating that a well defined transition state must be involved in these cyclizations. Extensive work was then conducted in probing the mechanism of this reaction which required developing several complementary routes to various homoallylic alcohol precursors. Indeed, results thus generated suggest that the more expected iodotetrahydrofuran (183) is not an intermediate and neither is the plausible epoxide (201). A strong link with hydroxytetrahydrofuran formation and the amount of water present in the reaction was established. That the ester group plays a key role in the cyclization was evident from the observation that its repositioning (135) or removal (137) gave only iodo-diols (204-5 and 221-2) which failed to cyclize further. Similar cyclizations of the corresponding E-isomers gave iodotetrahydrofurans (199) in excellent yield. In each case, the cyclization was reasonably stereoselective with a modest improvement in yields being obtained in anhydrous solvents. However, under a variety of conditions, these did not lead to hydroxytetrahydrofurans. lodoetherification of simpler Z - and E-3-hydroxy-5-alkenes proceeded efficiently with high levels of stereoselection by a 5-endo-trig process and gave iodotetrahydrofurans, but only when anhydrous acetonitrile was used as solvent. The E-alk-5-en-ols gave a stereoselective reaction and the Z-isomers showed poorer selectivity. In semi-aqueous conditions iodo-diols and not hydroxytetrahydrofurans were obtained. Displacements on the iodotetrahydrofurans with azide (240) and hydroxide (243) equivalents have also been demonstrated in which the inverted products are obtained in good yield as single isomers. The relevance of all these tetrahydrofurans in Natural Product assembly is then emphasized by a few specific examples.

Azatriquinacene (10-Azatricyclo[5.2.1.0"10]deca-2,5,8-triene) and azatriquinadiene (10-Azatricyclo[5.2.1.01"0]deca-2,8-diene) have been synthesised in respectively eight and seven steps from pyrrole. 27 Woodward dimerisation4 of azatriquinacene has beenattempted although no evidence of diazadodecahedraneh as yet been found. A unique nonacyclic species (10-Azatricyclo[5.2.1.0''10]-2,9-bis[1-azatricyclo [5.2.1.01'10]decane]dec-l-eneh) as been obtained by trimerisation of an enamine.Its structure and extraordinarily high basicity (pKa 25.1) make it a new class of "proton sponge". During this study thirteen new substituted azatriquinanes and four new substituted azabicycles have been synthesised, and nine crystal structures have been solved, providing valuable insights into the chemistry and structure of this novel heterocyclic system. The synthesis of a DNA building block containing a linker with an amine has been accomplished and its capacity to accommodate interesting molecules in an internal position of an oligonucleotide was proved by the attachment of the amino acid arginine. The coupling of the above dinucleotide with bis(disopropylamino)cyanoethyl phosphite has been achieved with the aim of making this material suitable for solid support synthesis as used in automated DNA synthesisers. A new methodology for the synthesis of H-phosphonates has been developed based upon three nucleophilic substitutions onto phosphorus trichloride in one pot. We have developed an easy and efficient way to carry out the palladium catalysed cross-coupling reactions using sealed, thick walled reaction vials. A new method for the synthesis of alkynylphosphonates from 1,1-dibromo-l-alkenes has been developed and the synthesis of a new alkyne-containing thymidine dimer has been achieved. Vinylphosphonate-linked dinucleotides have been prepared using an olefin crossmetathesis reaction as a key step.

Chapter One gives an introduction to the key concepts of bridgehead alkene formation and its relevance to the formation of bridgehead enolates of ketones including a review of bridgehead enolates in synthesis. The review is limited to the generation of bridgehead carbanions alpha to a carbonyl group and does not cover bridgehead cations, radicals or any anions except those already mentioned. In addition, a brief introduction to chiral base methodology and a review of the latest developments is included. Chapter Two describes the generation of bridgehead enolates in various bridged bicyclic ketones using chiral and achiral lithium amide bases and their subsequent interception with chlorotrimethylsilane. The chiral bridgehead silanes resulting from enantioselective deprotonation were shown to undergo silyl exchange reactions with TBAT as fluoride source in the presence of various electrophiles. Chapter Three describes a review of bridgehead enolates of imides and describes the extension of the developed methodology in Chapter Two to the generation and trapping of bridgehead enolates in bridged bicyclic imides and lactams. In addition bridgehead enolates are shown to react in the presence of non-classical in situ electrophiles such as methyl iodide, allyl bromide, benzyl bromide, prenyl bromide and pivaloyl chloride in high yield and enantioselectivity. The secondary bridgehead deprotonation of monosubstituted imides was also achieved resulting in double bridgehead functionalised products with high ee. The bridgehead silanes are shown to undergo silyl exchange reactions and display silyl directed regioselective reduction and thionation reactions. The mechanism of deprotonation, comparison to known examples and the origin of bridgehead carbanion stability are discussed. Chapter Four contains the experimental procedures and analytical data for the preparation of the novel compounds described herein followed by the appendix of selected NMR and X-ray data.

The work presented in this thesis hinges on three main topics: a) the coordination chemistry of symmetric and asymmetric derivatives of [9]aneN3 towards lanthanide ions; b) the transition metal co-ordination chemistry of nitrile and amino derivatives of [9]aneN3 and [15]aneN3O2; c) the use of macrocyclic ligands for the synthesis of polymeric Ag' complexes. Chapter 3 describes the Ln"' complexes of the ligand obtained by Schiffbase condensation of 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane (L) with three molar equivalents of sodium pyruvate using the Ln0' ion as templating agent. The mononuclear complexes [Ln(La)] (Ln"' = Y10, Sm"', Gd"', Dy"', Eu", Yb"', La"') have been prepared and characterised, and in most cases the crystal structure has also been determined. NMR spectroscopic studies on the diamagnetic [Y(La)] and [La(La)] complexes and on paramagnetic [Yb(La)] and [Sm(La)] complexes have been carried out. Variable temperature 1H NMR behaviour of the [Y(La)] and [Yb(La)] complexes has also been investigated. Hydrolysis experiments on the [La(La)] complex in D20 at neutral and acidic pH have been performed in order to determine the stability of such a complex in in vivo conditions. Moreover, lanthanide properties such as relaxivity of the Gd"' complex and Dysprosium Induced Shift (DIS) have been determined in order to obtain information either about the efficiency as contrast agent of the Gd"' complex and the number of water molecules bound to the metal centre. After the study on the nine co-ordinate complexes [Ln(La)] discussed in Chapter 3, Chapter 4 reports the Ln°1 complexes obtained by changing the ketone employed for the Schiff-base condensation with the triamine L. Two different acetylphosphonate monoesters have been used in order to form novel nine co-ordinate Ln"' complexes: the synthesis of [Ln(Lb)] (Ln"' = Y"', Gds", Yb"', La'y') and [Ln(Lc)] (Ln"' = Y"", Gd"', Eu") complexes has been achieved by Schiffbase condensation of the triamine (L) with methyl sodium acetyl phosphonate and methoxybenzyl sodium acetyl phosphonate, respectively, using the Ln01 ion as templating agent. These Ln"' complexes have been studied again by X-ray crystallography and NMR spectroscopy. Since the nine co-ordinate lanthanide complexes such as [Ln(Lb)] and [Ln(L`)] contain three chiral phosphorus centres, four possible diastereomers, each of them with two enantiomers, could be distinguished and NMR spectroscopic studies have been carried out in order to determine the four different diastereomers present in solution. As in Chapter 3, hydrolysis experiments on the Y" complexes with Lb and Lc and relaxivity ofthe Gd1° complexes have been determined. The ligands discussed in Chapter 5 have been synthesised in order to provide a set of seven or eight donor atoms for the co-ordination of lanthanide ions, leaving one or two co-ordination sites available for the binding of water molecules. Therefore, 4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (L2), 1-(carboxymethyl)-4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (HL3) and 1-(2-hydroxyethyl)-4,7-bis(2-aminoethyl)-1,4,7-triazacyclononane (HL4) have been synthesised and then reacted with two equivalents of sodium pyruvate, methyl sodium acetyl phosphonate or methoxybenzyl sodium acetyl phosphonate using the Ln" ion as templating agent. A large number of lanthanide complexes with formulations [Ln(L2a)(CH3CO2)], [Ln(L2b)(CH3CO2)], [Ln(L2°)(CH3CO2)], [Ln(L3a)] [Ln(L3b)], [Ln(L4a)] and [Ln(L4b)] have been synthesised and characterised. The single crystal X-ray diffraction analysis of [Gd(L2a)(CH3CO2)]"CH30H, the 1H and 13C NMR spectra and the hydrolysis experiments on the V" complexes with L 2a, L2b, L2c, L3a, L3b, L 4a and L 4b are reported. Relaxivity of the Gd" complexes and Dysprosium Induced Shift on [Dy(L2a)(CH3CO2)], [Dy(L3a)] and [Dy(L4a)] have been determined. Chapter 6 describes the co-ordination chemistry of symmetric and asymmetric derivatives of [9]aneN3 towards transition metal ions. The two ligands tris(cyanomethyl)- and tris(2-cyanoethyl)-1,4,7-triazacyciononane (L' and L5, respectively) form peculiar complexes with Cull: using Cu(BF4)2.4H20 in MeOH at 65°C, the methanolysis of two nitriles with formation of imino-ether groups have produced square-based pyramidal Cull complexes. However, from the reaction of L5 with CuC12.2H2O in CH3CN at room temperature, the distorted square-based pyramidal Cull complex [Cu(L5)C12] with the nitrite pendant arms left uncoordinated has been formed. Cull and Zn" complexes with 1-(2-aminoethyl)-1,4,7-triazacyclononane (L7), Mn", Nil', Cull and Zn" complexes with L2, Mn", Cull and Zn" complexes with 1,4,7-tris(3-aminopropyl)-1,4,7 triazacyclononane (L) and Mn" and Zn" complexes with HL3 and HL4 have been prepared and characterised, and in most cases the crystal structure has also been determined. Furthermore, the EPR spectra of the Cull complexes and the 13C NMR spectroscopic data for the Zn" complexes are reported. Synthesis, solution studies and structural characterisation of complexes with [15]aneN302 derivatives are the topics of Chapter 7. The two ligands 1,4,7-tris(cyanomethyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L8) and 1,4,7-tris(2-aminoethyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L9) have been synthesised and their co-ordination chemistry towards transition and posttransition metal ions (Cull, Zn°, Cd" and Pbll) has been studied. Most of the complexes have been structurally characterised and they all show interesting structures: the pendant nitrile arms of L8 are not involved in co-ordination of the metal except for the Pbl' crystal structure and with L9 only larger metal ions such as Cd" and Pbll are bound to all the donor atoms of the ligand. The protonation equilibria of the two ligands and the formation of the Cu", Zn", Cd" and Pb" complexes with L8 and L9 have been studied by means of potentiometric measurements. The protonation constants of the ligands and the stability constants of the complexes are reported and compared to other ligands with similar macrocyclic framework and donor atoms. In order to further investigate the structural features of the complexes in solution, 'H NMR spectra of diamagnetic complexes have also been recorded at various temperatures. In Chapter 8, the nitrite pendant arm derivatives L', L5, L8 and L1° have been used as building blocks for the synthesis of extended inorganic architectures by reaction with Ag'. The complexes {[Ag(L')]PF6},,,, {[Ag(L')]BF4}oo, {[Ag(L8)]BF4}. and [Ag(L10)]PF202 have been prepared and structurally characterised. Analogously to other complexes of the same type prepared in the Schröder group, these compounds show nuclearity and dimensionality strictly dependent upon the number and length of the nitrite functionalised pendant arms present in the ligand: these act as linkers between different metal centres. Ag' complexes of [9]aneN3 and [15]aneN302 derivatives bearing three 7-methylquinoline pendant arms have also been prepared and characterised. The crystal structure of the Ag' complex with 1,4,7-tris(7-methylquinolyl)-1,4,7-triaza-10,13-dioxacyclopentadecane (L12) shows theformation of a dimer {[Ag2.5(L12)(PF202)2.5"CH3CN]2w}i th one Ag' co-ordinated linearly by two heterocyclic N-donors and bridging the two units.