Tertiary-phosphine stabilised gold and copper complexes have been prepared with the intention to deposit elemental metal from solution. These complexes were intended to be delivered as a component of an ink on to a suitable substrate by an ink-jet printing process. Testing the compatibility of these complexes with ink-jet technology has been undertaken by Avecia and Seiko-Epson (this project's industrial sponsors). Four methyl(tertiary-phosphine)gold(I) complexes with a general molecular formula, [R₃PAuCH₃] (R = Ph, Ph-<i>p</i>-F, Ph-<i>p</i>-OMe and Me) were prepared by reacting (tertiary-phosphine)gold(I) chloride with methyllithium. Toluene-d₈ and decalin solutions of these complexes were heated to 100°C and the rate of decomposition of each complex to gold(O), tertiary-phosphine and ethane was measured spectroscopically by NMR and GC respectively. Relatively the gold(I) complexes were found to decompose in the following order: Ph-p-F > Ph > Me >> Ph-p-OMe A series of tertiary-phosphine stabilised copper(I) aryloxide complexes, with the general molecular formula [{(RO)Cu(PR'₃)_m}_n], were synthesised with the intent to duplicate the results obtained for the gold(I) complexes with a copper system. All the copper(I) complexes prepared were found to be too thermally stable to be suitable for the aim of the project. During the course of this project it was noted that the steric and electronic factors involved in producing the thermodynamic product from the reaction mixture were of major importance in the design of such complexes. Increase in overall steric bulk was, as expected, found to lead to copper(I) ions with lower coordination numbers while an increase in the electron affinity of the ligands was found to produce complexes with copper ions with higher coordination numbers.

The thesis is divided into four chapters: (1) Introduction (2) Results and discussion on the reactions of cyclobutenedione derivatives and related molecules with low-valent transition metal complexes. (3) A kinetic study of the ring-expansion reactions of some cyclobutenedione derivatives by platinum(O) complexes and (4) Experimental. Chapter 1. This chapter gives a general survey of the reactions of organic molecules containing small rings with transition metal complexes. The review concentrates on three-and four-membered ring compounds having both electron-donating and electron-withdrawing substituents in their reactions with the later transition metals. Particular accent is placed on the metals iron, rhodium, palladium and platinum. Chapter 2. The reactions of cyclobutenedione derivatives and related molecules with transition metal complexes are discussed. Hypotheses are put forward to account for the variation of products found in these reactions when both the nature of the substituent groups in the organic molecule and the transition metal complex are changed. The spectroscopy results obtained for these complexes are discussed. Chapter 3. A kinetic study of the ring-expansion reactions of some cyclobutenedione derivatives by platinum(O) complexes is described. The reactivities of the species Pt(PPh3)2 and Pt(AsPh3)2 are compared, and a theory concerning the solution characteristics of Pt(AsPh3)2 is put forward. Chapter 4. All experimental details are given for the reactions studied in chapters 2 and 3. All analysis results, infrared and n.m.r. spectra are detailed.

In order to elucidate the mechanism of action of AMD3100, 1 synthesised several metal-cyclam complexes, metal complexes of xylyl-bicyclam, AMD3329 and its component macrocycle, and their metal complexes. Xylyl-bicyclam was synthesised, and complexed with palladium, nickel, copper and cobalt. 1D and 2D ¹H, ¹³C and ¹⁵N NMR studies revealed that [Pd₂(xylyl-bicyclam)](OAc)₄ exists as one major configuration in aqueous solution, the <i>trans</i>-III configuration. The addition of acetate to this solution did not induce any configurational change. NMR studies on [Ni₂(xylyl-bicyclam)](OAc)₄ showed it to be a mixture of paramagnetic and diamagnetic species in solution. Visible spectroscopy showed the main configuration to be square-planar. Two <i>trans </i>configurations of [Co₂(xylyl-bicyclam)Cl₄]Cl₂ were identified using 1D and 2D ¹H, ¹³C and ¹⁵N NMR spectroscopy. Upon addition of acetate to this complex, configurational changes occur, eventually to give one <i>trans</i> configuration. Mass spectrometry on this product showed it to be [Co₂(xylyl-bicyclam)(OAc)₄](OAc)₂. AMD 3329 and its component macrocycle were synthesised, and complexed with Cd(II), using NMR-active enriched ¹¹¹Cd. Using 1D and 2D ¹H, ¹³C, ¹⁵N and ¹¹¹Cd NMR spectroscopy, these novel metallomacrocycles were fully characterised, and two configurations were found in solution for both the ¹¹¹Cd-macrocycle and the analogous AMD 3329 complex. The monomer was also complexed with Zn(III), and NMR studies showed it to exist also in two configurations in solution. Addition of excess acetate to the Zn(II) complex did not induce any configurational change in the macrocyclic framework. The interaction between Cu(II)-cyclam, Ni(II)-cyclam and Cu(II)₂-xylyl-bicyclam and lysozyme was studied. NMR spectroscopy revealed binding sites in lysozyme involving tryptophan residues. Solid-state x-ray crystallographic studies on the copper complexes showed the presence of two distinct binding sites. Polar and non-polar interactions were established in the protein recognition of the metallomacrocycles, including H-bonding between the cyclam ring and protein carboxylate groups, and hydrophobic stacking interactions. These studies provide the first direct demonstration of the mode of interaction between metal cyclams and proteins and the relevance to binding to the CXCR43 protein is discussed.

<i>Chapter 1</i> outlines the development of carbaborane and carbametallaborane chemistries and is consequently background to the work described in this thesis. Brief descriptions of the chemistry and bonding capability of the tertiary gold(I) fragment and of chemical studies related to BNCT are also presented. <i>Chapter 2</i> describes the synthesis and characterisation of a series of σ-bonded phosphine and arsine gold(I)carbaborane compounds, 1-R'-2-(ER_3Au)- 1,2-<i>closo</i>-C_2B_10H_10 (R' = Ph [<i>3</i>] or CH_3OCH_2 [<i>4</i>], ER_3 = PPh_3 [<i>a</i>], P(<i>o</i>-tol)_3 [<i>b</i>] PCy_3 [<i>c</i>], Pet_3 [<i>d</i>] or AsPh_3 [<i>e</i>]) by reaction between ER_3AuCl and the appropriate lithium carbaborane. The ^11B(^1H) NMR spectrum of 1-CH_3OCH_2-2-(PPh_3Au)-1,2-<i>closo</i>-C_2B_10H_10 (<i>4a</i>) is assigned by an ^11B-^11B COSY NMR experiment and by comparison with the (assigned) ^11B(^1H) NMR spectrum of 1-CH_3OCH_2-1,2-<i>closo</i>-C_2B_10H_11 (<i>1</i>). Consideration of the ^11B(^1H) NMR and (where appropriate) ^31P(^1H) NMR chemical shifts of compounds <i>3</i> and <i>4</i> by comparison with related species implies that the <i>closo</i>-carbaborane ligands function as efficient electron donating groups. Comparison of the Au-C distance in 1-CH_3OCH_2-2-(AsPh_3Au)-1,2-<i>closo</i>-C_2B_10H_10 (<i>4e</i> and AsPh_3AuMe (<i>5</i>) suggests that the gold-carbon bond in the former is stronger. This is supported by analysis of the results from EHMO calculations on model compounds. Consequently, <i>closo</i>-carbaboranes bonded to metal atoms <i>via</i> a metal-carbon σ-bond are shown to be good σ-donor ligands. <i>Chapter 3</i> discusses the synthesis and characterisation of thermally stable σ-bonded titanium(IV) carbaborane compounds by reaction of TiCl<SUB>4</SUB> or CpTiCl<SUB>3</SUB> with lithium carbaborane. Reaction of Cp<SUB>2</SUB>TiCl<SUB>2</SUB> with one or two equivalents of lithium carbaborane yielded the decomposition product Cp<SUB>2</SUB>TiCl (<i>9</i>), though the latter reaction afforded a transient deep green species which is tentatively suggested as being a titanocene carbaborane compound. The molecular structure of 1-CH<SUB>3</SUB>OCH<SUB>2</SUB>-2-(CpTiCl<SUB>2</SUB>)-,1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>10</SUB>H<SUB>10</SUB> (<i>8</i>) was determined by X-ray crystallography and the Ti<SUP>IV</SUP> centre was found to be 7-coordinate as a result of intramolecular coordination by the oxygen atom of the substituent ether group. Comparison of the <SUP>11</SUP>B(<SUP>1</SUP>H) and <SUP>1</SUP>H NMR spectra of 1-CH<SUB>3</SUB>OCH<SUB>2</SUB>-2-(TiCl<SUB>3</SUB>)-1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>10</SUB>H<SUB>10</SUB> (<i>6</i>) and <i>8</i> allows the structure of the <i>6</i> to be proposed.

There are a large number of highly stable systems which are isostructural and isoelectronic to carboxylates. One of these, amidinates, the 1,3-nitrogen analogues of carboxylates, show a rich and varied coordination to both main group and transition metals. However, the triaza analogues, substituted guanidinates, had received little or no attention as ligands prior to this work, in which the ligand chemistry of neutral, mono- and dianionic guanidines has been explored. The synthesis and characterisation of tri-substituted guanidines containing a variety of alkyl (<i>ⁱ</i>Pr, <i>^l</i>Bu, Cyx) and aryl (Ph, <i>p</i>-tol) substituents is described herein. Preparation of the homochiral substituted N,N',N"-tris((s)-(-)-amethylbenzyl)guanidine and the X-ray crystal structure of its HPF₆ salt are also presented. In the solid state the central CN₃ unit exhibits local C₃ symmetry and has steric elements on one of the plane resulting in two stereochemically different faces. The formation of tetra-substituted N,N-diethyl-N',N"-diphenylguanidine is also detailed. Formation of complexes containing neutral guanidine ligands was achieved in the reactions of N,N',N"-triphenylguanidine with CoCl₂ and Ag(SO₃CF₃). The complexes formed, [Co{PhN=C(NHPh)₂]₂Cl₂] and [Ag{PhN=C(NHPh)₂}₂][SO₃CF₃] respectively, were characterised by X-ray crystallography and found to contain monodentate guanidine ligands bound through their imine nitrogen alone. The cobalt complex adopts pseudo-tetrahedral geometry while [Ag{PhN=C(NHPh)₂}₂] is perfectly linear at silver with the triflate acting only as a counterion. Cleavage reactions of the ruthenium chloro-bridged dimers [(<i>p</i>-cymene)RuCl₂]₂ and [Cp*RuCl₂]₂ with various tri-substituted guanidines were undertaken. Two product obtained from these reactions, namely [(<i>p</i>-cymene)Ru{h²-(<i>ⁱ</i>PrN)₂CNH<i>ⁱ</i>Pr}Cl] and [Cp*Ru{(h⁶-<i>p</i>-tol)N=C(NH<i>p</i>-tol)₂}]⁺, were characterised by X-ray crystallography. The first of these contains a ruthenium centre with a h⁶-arene, terminal chloride and monodeprotonated chelating guanidinate ligand. Meanwhile the second is a sandwich compound in which the guanidine is bound through an arene substituent and not one of its nitrogens.

No description available.

This thesis investigates the effect of varying the ligand component in a cluster forming reaction recently developed for the synthesis of molecules with general formula, [Cu_x+y(C≡CR)_x(hfac)_y] where hfac is 1,1,1,5,5,5-hexafluoropentanedione and C≡CR is a straight chain terminal alkynyl ligand (R = -C₃H₇, -C₄H₉, -C₅H_11­, - C₆H₁₃). Using the ‘bulky’ alkynyl ligands, 3,3-dimethyl-1-butyne (^tBuC≡CH) and trimethylsilylacetylene (Me₃SiC≡CH) has led to the successful isolation of five clusters containing ten or twelve copper atoms. These molecules are structurally related to a family with formula, [Cu₄(aryl)₄] and display an alkynyl bridged Cu₄ central core ‘capped’ by peripheral Cu-hfac chelate rings. Six additional clusters are reported that have nuclearities ranging between sixteen and twenty-six copper atoms. These were obtained by replacing hfacH with the trifluorinated 1,3-diketonyl ligands, 4,4,4-trifluoro-1-phenyl-1,3-butanedione, (Ph-tfacH), 4,4,4-trifluoro-1-phenyl-1,3-butanedione (^tBu-tfacH) and 1,1,1-trifluoro-2,4-pentanedione (tfacH) or using 3,3-dimethyl-1-butyne (^tBuC≡CH) or 3-phenyl-1-propyne (PhCH₂C≡CH) in the cluster forming reaction. The new additions to the [Cu_x+y(C≡CR)_x(hfac)_y] family of molecules are diverse in nuclearity and display interesting structural features. Using alkynyl or 1,3-diketone ligands with bulky substituents affects the ability of the clusters to adopt a ‘conventional’ structure and as a result interesting structural variations are observed. Using ligands with substituents that are able to form weak but significant π-stacking type intramolecular interactions also causes a distortion from a ‘conventional’ structure. There is an interesting common structural motif that appears throughout the [Cu_x+y(C≡CR)_x(hfac)_y­] family. This motif has the formula, [Cu₄(C≡CR)₄(Cu-hfac)_x] and all the clusters in the series are found to contain one, two or three such fragments.

<i>Chapter 1</i> gives an overview of carbaborane chemistry, including concepts of cluster bonding and slip distortions in carbametallaboranes derived from [7,8-<i>nido</i>-C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>11</SUB>]<SUP>2-</SUP>. This is followed by an introduction to the transition metal chemistry of fused aromatic ligands, with specific reference to the similar bonding capabilities of these and carborane species. Finally, the structure of 3-(η5-C<SUB>9</SUB>H<SUB>7</SUB>)-3,1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>11</SUB> (1) is discussed with rationalisation of the observed <i>cisoid</i> molecular conformation. <i>Chapter 2</i> comprises two sections, <i>A</i> and <i>B. Section A</i> presents the syntheses and structures of three indenyl carbametallaboranes, 1-Ph-3-(η5-C<SUB>9</SUB>H<SUB>7</SUB>)-3,1,2-<i>closo</i>C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>10</SUB> (2), 1-(CH<SUB>2</SUB>OCH<SUB>3</SUB>)-3-(η5-C<SUB>9</SUB>H<SUB>7</SUB>)-3,1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>10</SUB> (3) and 1,2-(CH<SUB>2</SUB>OCH<SUB>3</SUB>)<SUB>2</SUB>-3-(η5-C<SUB>9</SUB>H<SUB>7</SUB>)-3,1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>9</SUB> (4). In 2 and 3 the indenyl ligand adopts a conformation analogous to that in 1, i.e. the indenyl ring junction carbon atoms are <i>cisoid</i> with respect to the cage carbon atoms. In 4 the presence of two ether substituents has resulted in the adoption of the 'next best' staggered conformation. A series of EHMO calculations performed on idealized models of 1-4 predict theoretical energy minimum conformations in broad agreement with those observed crystallographically. <i>Section B</i> describes the synthesis and structural determination of the first reported fluorenyl carbametallaborane complex, 3-(η5-C<SUB>13</SUB>H<SUB>9</SUB>)-3,1,2-<i>closo</i>-C<SUB>2</SUB>B<SUB>9</SUB>H<SUB>11</SUB> (5). The molecular conformation has been rationalised in terms of the <i>trans</i> influence of the facial cage boron atoms, and is in full accord with that predicted by the results of EHMO calculations on an idealised model of 5.

No description available.

This thesis is concerned with the synthesis and characterization of novel Ru^II arene anti-cancer complexes, containing different arenes and chelating ligands, especially arenes that can act as intercalators and chelating ligands that are redox-active. Synthesis and characterization of complexes of the type [(<i>H</i>⁶-arene)Ru(en)Cl]⁺, where the arene is <i>ortho-</i>, <i>meta</i>- or <i>para-</i>terphenyl (<i>o-, m- </i>or <i>p</i>-terp) are reported. [(<i>H</i>⁶-<i>p</i>-terp)Ru(en)Cl]⁺ has a similar potency to cisplatin and much higher activity against cancer cell lines than <i>o</i>- and <i>m</i>-terp analogues. The <i>p</i>-terp complex binds to DNA rapidly and quantitatively and the experimental data are consistent with combined intercalative and monofunctional (coordination) binding mode of [(<i>H</i>⁶-<i>p</i>-terp)Ru(en)Cl]⁺. The <i>o</i>- and <i>m</i>-terp analogues bind to DNA preferentially through coordination of ruthenium. The synthesis and characterization of Ru^II arene complexes containing 2,2’-bipyridine (bipy), 2,2’-bipyridine-3,3’-diol (bipy(OH)₂) or deprotonated 2,2’-bipyridine-3,3’-diol (bipy(OH)O) as chelating ligands and different arenes are reported, including several x-ray crystal structures. In aqueous solution only the deprotonated (bipy(OH)O) form of the 2,2’-bipyridine-3,3’-diol is present in the complexes. Hydrolysis of these complexes in aqueous solution is relatively fast (37°C) and when the arene is biphenyl, initial aquation is followed by partial arene loss. Complexes with bipy(OH)O as chelating ligands, in general exhibit good cytotoxicity towards A2780 human ovarian cancer cells. Oxidation of the <i>o</i>-phenylenediamine (<i>o</i>-pda) chelating ligand in [(<i>H</i>⁶-arene)Ru(<i>o</i>-pda)Cl]⁺ to <i>o</i>-benzoquinonediimine (<i>o</i>-bqdi) leads to loss of cytotoxic activity. The x-ray crystal structures of [(<i>H</i>⁶-<i>p</i>-cym)Ru(<i>o</i>-pda)Cl][PF₆] and [(<i>H</i>⁶-hmb)Ru(<i>o</i>-bqdi)Cl][PF₆] are reported.