L’objectif consistant à élaborer des «aimants par conception» peut être atteint en adaptant les structures moléculaires des complexes de coordination. Les molécules conçues devraient présenter les caractéristiques requises pour des applications spécifiques, qui résultent de leur riche diversité structurale. Des complexes mononucléaires à base de Ni avec une grande anisotropie magnétique et des molécules polynucléaires à base de Ni et de Co sont préparés et étudiés dans cette thèse. Les synthèses, les études magnétiques et les propriétés électrochimiques des complexes contenant un ligand pontant non innocent sont étudiées. Les complexes mononucléaires Ni(II) à géométrie bipyramide trigonale sont préparés avec des ligands axiaux et les contre-anions différents. L'effet de la nature des ligands axiaux et du changement structural induit par les contre-anions sur l'anisotropie magnétique est étudié expérimentalement et analysé à l'aide de calculs théoriques. Des molécules organiques sont utilisées pour concevoir des complexes trinucléaires à grande anisotropie magnétique et à couplage d'échange faible. Plusieurs complexes polynucléaires à base de Ni et de Co où le TTC³⁻ agit comme un ligand pontant innocent et le HHTP³⁻ comme un ligand non innocent typique sont cristallisés avec diverses structures (TTC = Trithiocyanurate; HHTP = Hexahydroxytriphénylène). Pour les complexes contenant le ligand non innocent (HHTP), les anions radicalaires sont produits par électrochimie. La combinaison de la spectro-électrochimie et de la spectroscopie à résonance paramagnétique électronique couplée à des études d'électrochimie permet d'étudier la délocalisation des électrons sur les radicaux organiques générés et le couplage d'échange entre les ions métalliques. / The objective of elaborating “magnets by design” can be achieved by tailoring the molecular structures of coordination complexes. The designed molecules are expected to exhibit the characteristics required for specific applications, virtually resulting from their rich structural diversity. Mononuclear Ni-based complexes with large magnetic anisotropy and polynuclear Ni- and Co-based molecules are designed in this dissertation. The syntheses, magnetic studies, and electrochemical properties of the complexes containing non-innocent bridge ligand are investigated. The Ni(II) mononuclear complexes with trigonal bipyramid geometry are prepared by tuning the axial ligands and the counter anions. The effect of the nature of the axial ligands and the structural change induces by the counter anions on magnetic anisotropy is studied experimentally and analyzed with the help of theoretical calculations. Large organic molecules are used to design trinuclear complexes with large magnetic anisotropy and weak exchange coupling. Several polynuclear Ni- and Co-based complexes with TTC³⁻ acting as an innocent bridging ligand and HHTP as a typical non-innocent ligand, are crystallized with various structures (TTC = Trithiocyanurate; HHTP = Hexahydroxytriphenylene). For the complexes containing the non-innocent ligand (HHTP), radical anions are produced by electrochemistry. The combination of spectroelectrochemical and Electron Paramagnetic Spectroscopy coupled to electrochemistry studies allow investigating the delocalization of the electrons on the generated organic radicals and the exchange coupling among the metal ions.

This thesis describes the synthesis of a host of polynuclear iron complexes synthesised with phenolic oxime ligands, fundamentally developing the coordination chemistry of iron with these ligands. The metallic cores that occur within iron phenolic oxime clusters were found to contain almost exclusively oxo-centred triangles and oxo-centred tetrahedra. We found that we could alter the reaction conditions or derivatise the ligands and develop these basic building blocks into more elaborate arrays, exerting a degree of control over creating larger or smaller clusters. Chapter one describes the syntheses, structures and magnetic properties of new iron complexes alongside previously synthesised related complexes (4, 5, 8, 9 and 15) containing salicylaldoxime (saoH2) or derivatised salicylaldoximes (RsaoH2). These are [Fe3O(OMe)(Ph-sao)2Cl2(py)3]·2MeOH (1·2MeOH), [Fe3O(OMe)(Ph-sao)2Br2(py)3]·Et2O (2·Et2O), [Fe4(Ph-sao)4F4(py)4]·1.5MeOH (3·1.5MeOH), [Fe6O2(OH)2(Et-sao)2(Et-saoH)2(O2CPh)6] (4), [HNEt3]2[Fe6O2(OH)2(Et-sao)4(O2CPh(Me)2)6]·2MeCN (5·2MeCN), [Fe6O2(O2CPh)10(3-tBut-5-NO2-sao)2(H2O)2]·2MeCN (6·2MeCN), [Fe6O2(O2CCH2Ph)10(3-tBut-sao)2(H2O)2]·5MeCN (7·5MeCN), {[Fe6Na3O(OH)4(Me-sao)6(OMe)3(H2O)3(MeOH)6]·MeOH}n (8·MeOH) and [HNEt3]2[Fe12Na4O2(OH)8(sao)12(OMe)6(MeOH)10] (9). The predominant building block appears to be the triangular [Fe3O(R-sao)3]+ species which can self-assemble into more elaborate arrays depending on reaction conditions. The four hexanuclear and two octanuclear complexes of formulae [Fe8O2(OMe)4(Mesao) 6Br4(py)4]·2Et2O·MeOH (10·2Et2O·MeOH), [Fe8O2(OMe)3.85(N3)4.15(Mesao) 6(py)2] (11), [Fe6O2(O2CPh-4-NO2)4(Me-sao)2(OMe)4Cl2(py)2] (12), [Fe6O2(O2CPh-4-NO2)4(Et-sao)2(OMe)4Cl2(py)2]·2Et2O·MeOH (13·2Et2O·MeOH), [HNEt3]2[Fe6O2(Me-sao)4(SO4)2(OMe)4(MeOH)2] (14) and [HNEt3]2[Fe6O2(Etsao) 4(SO4)2(OMe)4(MeOH)2] (15) all are built from series of edge-sharing [Fe4( μ4- O)]10+ tetrahedra. Complexes 10 and 11 display a new μ4-coordination mode of the oxime ligand and join a small group of Fe-phenolic oxime complexes with nuclearity greater than six. Chapter three then introduces co-ligands to the reaction scheme to compete with the salicylaldoxime ligands for metal coordination sites. Five tetranuclear and two nononuclear complexes are stabilised with salicylaldoxime (saoH2) or derivatised salicylaldoximes (R-saoH2) in conjunction with either 1,4,7- triazocyclononane (tacn), 2-hydroxymethyl pyridine (hmpH) or 2,6-pyridine dimethanol (pdmH2), [Fe4O2(sao)4(tacn)2]·2MeOH (16·MeOH), [Fe4O2(Mesao) 4(tacn)2]·2MeCN (17·2MeCN), [Fe4O2(Et-sao)4(tacn)2]·MeOH (18·MeOH), [Fe9NaO4(Et-sao)6(hmp)8]·3MeCN·Et2O (19·3MeCN·Et2O), [Fe4 (Etsao) 4(hmp)4]·Et-saoH2 (20·Et-saoH2), [Fe4(Ph-sao)4(hmp)4]·2MeCN (21·2MeCN) [Fe9O3(sao)(pdm)6(N3)7(H2O)] (22). Chapter four straps two salicylaldoxime units together in the 3-position, using ligands with aliphatic a,W-aminomethyl links, allowing the assembly of the polynuclear complexes [Fe7O2(OH)6(H2L1)3(py)6](BF4)5·6H2O·14MeOH (23·6H2O·14MeOH), [Fe6O(OH)7(H2L2)3][(BF4)3]·4H2O·9MeOH (24·4H2O·9MeOH) and [Mn6O2(OH)2(H2L1)3(py)4(MeCN)2](BF4)5(NO3)·3MeCN·H2O·5py (25·3MeCN·H2O·5py). In each case the metallic skeleton of the cluster is based on a trigonal prism in which two [MIII 3O] triangles are tethered together via three helically twisted double-headed oximes. The latter are present as H2L2- in which the oximic and phenolic O-atoms are deprotonated and the amino N-atoms protonated, with the oxime moieties bridging across the edges of the metal triangles. Both the identity of the metal ion and the length of the straps connecting the salicylaldoxime units have a major impact on the nuclearity and topology of the resultant cage, with, perhaps counter-intuitively, the longer straps producing the “smallest” clusters.

The novel trinuclear complex, BBR3464 has undergone Phase II clinical trials and been shown to have greater cytotoxicity and cellular uptake than clinical anticancer platinum drugs such as cisplatin, oxaliplatin and carboplatin. The clinical efficacy of cisplatin, oxaliplatin and carboplatin is limited due to acquired resistance and dose limiting side effects. The three major pharmacological factors contributing to the intrinsic cytotoxicity of, and cellular resistance to, platinum drugs are (i) cellular uptake and efflux of platinum; (ii) the frequency and nature of Pt-DNA adducts; and (iii) deactivating metabolic reactions with sulfur-containing nucleophiles. Since decreased cellular uptake of platinum drugs is a common feature of resistant cells, investigating mechanisms of cellular uptake and efflux is of a great importance in the field of cancer biology. The mechanisms of uptake of Platinum drugs are diverse and complex. Similar to cisplatin, BBR3464 v as shown to use copper transporter hCTR1 and ATP7B for influx and efflux respectively. Organic cation transporters (OCT) did not play an important role in BBR3464 cellular uptake, however, desipramine, an OCT inhibitor had synergistic effects on platinun drugs-induced cytotoxicity. This effect is of high clinical relevance since desipramine, an antidepressant, is being used in prostate cancer patients for the treatment of neuropathic pain. The mechanism of this interaction was further addressed.Due to the high charge of BBR3464, studies have shown that its DNA binding has a non-covalent component. To examine the non covalent component, labile chloride leaving groups were replaced by non labile ammonia groups. Besides having higher cellular accumulation than BBR3464, the non covalent analogue, AH78, had a different mechanism of action in cells and showed promising results in vivo. These data confirm the validity of searching for new chemotypes outside the cisplatin structural class to aid in the treatment of recurrent, cisplatin-resistant cancers.

A combined experimental and computational study on the reversible ortho-metalation exhibited by the triosmium cluster Os3(CO)10(dppm) (dppm = 1,1-bis(diphenylphosphino)methane is reported. The conversion of nonacarbonyl cluster HOs3(CO)9[-PhP(C6H4)CH2PPh2] to Os3(CO)10(dppm) is independent of added CO and exhibits a significant inverse equilibrium isotope effect (EIE). Reductive coupling of the C-H bond in HOs3(CO)9[-PhP(C6H4)CH2PPh2] leads to the formation of agostic C-H and two distinct aryl-π species prior to the rate-limiting formation of the unsaturated cluster Os3(CO)9(dppm). Heating the unsaturated dimer H2Re2(CO)8 with Cp*Rh(CO)2 (Cp* = 1,2,3,4,5-pentamethylcyclopentadiene) at elevated temperature affords the new trimetallic clusters H2RhRe2Cp*(CO)9 and HRh2ReCp*2(CO)6, and the spiked-triangular cluster HRhRe3Cp*(CO)14. H2Re2(CO)8 reacts with Cp*2Rh2(CO)2 under identical conditions to furnish H2RhRe2Cp*(CO)9 and HRh2ReCp*2(CO)6 as the principal products, in addition to the tetrahedral cluster H2Rh2Re2Cp*2(CO)8. H2RhRe2Cp*(CO)9 undergoes facile fragmentation in the presence of halogenated solvents and the thiols RSH (where R = H, C6H4Me-p) to afford the structurally characterized products Cp*Rh(-Cl)3Re(CO)3, S2Rh3Cp*(CO)4, Cp*Rh(-Cl)(-SC6H4Me-p)2Re(CO)3, and Cp*Rh(-SC6H4Me-p)3Re(CO)3. The new hydrazido-substituted compounds TaCl(NMe2)3[N(TMS)NMe2] (TMS = tetramethylsilyl) and Ta(NMe2)4[N(TMS)NMe2] have been synthesized and their structures established by X-ray crystallography. The latter product represents the first structurally characterized octahedral tantalum(V) complex containing a single hydrazido(I) ligand in an all-nitrogen coordinated environment about the metal center. The fluxional properties of the amido and hydrazido ligands in these new compounds have been established by VT 1H NMR spectroscopy (VT = variable temperature). Preliminary data using Ta(NMe2)4[N(TMS)NMe2] as an ALD (ALD = atomic layer deposition) precursor for the preparation of tantalum nitride and tantalum oxide thin films are presented.

This investigation addresses the interrelated problems of A) Uptake and vascular transport of lipophilic chemical carcinogens, and intracellular interactions between lipoproteins and carcinogens; B) Biochemical mechanisms by which polynuclear aromatic hydrocarbon carcinogens inhibit the replicative and repair DNA synthesis in cells. The results observed in this study suggest that ingested benzo(a)pyrene (BaP) enters the gastrointestinal lymphatic drainage sequestered within lymphatic lipoproteins, and that low-density lipoproteins (LDL) play a major role in the vascular transport of BaP. BaP is taken up into cells by adsorptive endocytosis mediated by an interaction between apolipoprotein-specific receptors on the cell membrane and the specific apolipoproteins on LDL. Having entered peripheral cells sequestered within the lipid core of LDL, an electrophilic metabolite of BaP covalently binds to cellular DNA, and may interact with other cellular macro-molecules. Data presented here suggest that LDL is also absolutely required for the activation of DNA polymerase-a, which is the major enzyme of DNA excision repair necessary to correct the DNA damage caused by BaP. This study concludes that an active metabolite of the polynuclear aromatic hydrocarbon carcinogen, benzo(a)pyrene, suppresses DNA polymerase-a activity by inhibiting the binding of 2'-deoxyguanosine 5'-triphosphate to an acceptor site on the DNA polymerase-a complex with the DNA substrate, thereby competitively inhibiting interaction of 2'-deoxyguanosine 5'-triphosphate in the DNA synthetic process.

Yes / A highly porous carbon was synthesized using a coordination complex as an unusual precursor. During controlled pyrolysis, a trinuclear copper complex, [CuII3Cl4(H2L)2]·CH3OH, undergoes phase changes with melt and expulsion of different gases to produce a unique morphology of copper-doped carbon which, upon acid treatment, produces highly porous graphitic carbon with a surface area of 857 m2 g–1 and a gravimetric hydrogen uptake of 1.1 wt % at 0.5 bar pressure at 77 K. / EPSRC (EP/R01650X/1 for VPT, and EP/E040071/1 for MT) and the University of Bristol

Two types of oily waste sludges generated by a railroad maintenance facility were studied to reduce the volume of hydrocarbon waste. The specific goals of this laboratory study were to evaluate rate and extent of microbial degradation, benefits of organism addition, role of biosurfactant, and dewatering properties. The oily waste sludges differed in characteristics and contained a mixture of water, motor oil, lubricating oil, and other petroleum products. Degradation was measured using COD, suspended solids, GC measurements of extractable material, and nonextractable material concentration. Biosurfactant production was characterized using surface tension and polysaccharide measurements. Degradation of ten percent waste oil showed that the removal in a 91 day experiment was 75 percent for COD and suspended solids, 98 percent for extractable oil, and negligible for non-extractable material. It was concluded that methylene chloride extraction could be used to estimate degradation potential of a hydrocarbon waste. Addition of organisms increased the rate and extent of degradation over 22 days, but did not provide any benefits over 91 days. Data suggested that microorganisms degraded simple compounds first, then produced biosurfactants. It was thought that the biosurfactants remained attached to the organism membrane and increased solubility, stimulating the degradation of difficult to degrade waste oil. After oil was degraded the biosurfactants became ineffective. The dewatering properties of 10 percent oily sludge deteriorated with the production of biosurfactant and improved after the surfactant was degraded due to changes in oil solubility. / Master of Science

The last two decades have seen extensive growth in interest in metal-ion assemblies, especially for building new polynuclear exchange-coupled magnetic systems. However, the concept of designing polynuclear extended structures has still not matured to the level of retro-synthetic approach developed for the organic and pharmacological molecules. Although some progress has been made with secondary building units (SBUs) in metal-organic-frameworks (MOFs), the control seems to be just an illusion when it comes to bridging ligands such as the azide ion. When it is asserted that the azido ligand is versatile in its bridging capabilities, what is actually meant is that it would be difficult to predict or control its bridging properties, or in other words, the azido based polynuclear complexes are difficult to pre-design. However, this kind of serendipity is not always bad news for the chemists. For example, the azido ligand has been shown to mediate magnetic exchanges between paramagnetic metals in a predictable fashion (usually depending upon the bonding geometries). Therefore, it is a well-respected ligand in polynuclear assemblies of paramagnetic ions. Serendipitous assemblies offer new magnetic structures that we may not otherwise even think about synthesizing. Similarly, there are other ligands, such as alkoxido, oximato, carboxylato etc. which also behave like azide. These ligands are very important in the study of magnetic exchanges to develop an understanding of the underlying mechanisms in molecular magnetism. Serendipitous assemblies have also led to systems like single molecule magnets (SMMs), which have enriched the field with potential applications in computing and have also been used for the confirmation of the quantum magnetic properties like tunneling phenomenon, spin decoherence etc. Investigations incorporated in this thesis work led to several novel strategies for using serendipity as an advantage and build unprecedented structural topologies with interesting new molecular-magnetic properties. All the reported complexes were thoroughly analyzed through elemental analysis, spectroscopy, X-ray structure determination (both single crystal & powder diffractions) and variable temperature magnetic susceptibility measurements. In a few suitable cases, model structures obtained from the X-ray structures were also employed to study the magnetic exchange mechanisms through density functional theory (DFT) calculations and simulations. CHAPTER 1 of the thesis presents a general review on the ever-growing field of metal-ion assembly. In particular, the importance of the ‘serendipitous approach’ to build new and interesting metal-ion clusters and polyclusters is highlighted. This chapter also describes the basic concepts of exchange-based molecular magnetism as applied to the metal-ion assemblies. CHAPTER 2 describes the concept of using lower molar proportions of blocking bidentate chelating ligands in the neutral copper(II)-azido systems, which increases the number of coordination sites for the versatile azido bridges to assemble the metal-ions in higher dimensions, based on smaller cluster units. Syntheses, structures and magnetic properties of ten novel complexes are described in this chapter: [Cu3(tmen)2(N3)6]n (1), [Cu4(Me-hmpz)2(N3)8]n (2), [Cu4(men)2(N3)8]n (3), [Cu6(deen)2(N3)12]n (4), [Cu6(aem)2(N3)12]n (5), [Cu6(dmeen)2(H2O)2(N3)12]n (6), [Cu6(N,N'-dmen)2(N3)12]n (7), [Cu6(hmpz)2(N3)12]n (8), Cu5(N,N-dmen)2(N3)10]n (9), and [Cu5(N,N'-dmen)5(N3)10]n (10) [tmen = N,N,N',N'-tetramethylethylenediamine, Me-hmpz = 1-methylhomopiperazine, men = N-methylethylenediamine, deen = N,N'-diethylethylenediamine, aem = 4-(2-aminoethyl)morpholine, dmeen = N,N-dimethyl-N'-ethylethylenediamine, N,N'-dmen = N,N'-dimethylethylenediamine, hmpz = homopiperazine, N,N-dmen = N,N-dimethylethylenediamine]. Most of these complexes have simple oligonuclear basic building units (Scheme 1), such as trinuclear (1), tetranuclear (2, 3) and hexanuclear (4-8), but the overall arrangements of these cluster units in higher dimensions vary widely and serendipitously. For example, the hexanuclear complexes 4-7, although having almost identical basic structures, assemble in three- (4, 5) or two- (6, 7) dimensions with different connectivity among the basic structures. However, complex 9 is made from two different building units (Cu2 and Cu3). Complex 10, although having metal to blocking molar ratio 1:1, presents an unprecedented 1D structure for such complexes. Analysis of the magnetic susceptibility data for complexes 1-9 using theoretical exchange models for fitting is also described. Density functional theory (DFT, B3LYP) was employed to further analyze the experimental magnetic data for complexes 1, 2, 3 and 9 to better understand the magnetic exchange mechanisms in such systems. CHAPTER 3 continues with the same concepts developed in the previous chapter using multidentate neutral and anionic co-ligands. Using lower molar proportions of these multidentate ligands, seven novel complexes have been synthesized (keeping the initial metal to ligand ratio as 2:1): [Cu4(L1)2(N3)8]n (11), [Cu4(L2)2(N3)8]n (12), [Cu4(L3)2(N3)8]n (13), [Cu4(L4)2(N3)8]n (14), [Cu9(L5)4(N3)18]n (15), [Cu4(L6)2(H2O)2(N3)6] (16) and [Cu4(L7)2(N3)6]n (17) [where L1-5 are the condensation products of 2-pyridinecarboxaldehyde and 2-{2-(methylamino)ethyl}pyridine (L1), N,N-diethylethylenediamine (L2), N,N-dimethylethylenediamine (L3), N-methylethylenediamine (L4), N,N,2,2-tetramethylpropanediamine (L5); HL6 and HL7 are the condensation products of 2-hydroxy-3-methoxybenzaldehyde with N,N-diethylethylenediamine (HL6), and N-ethylethylenediamine (HL7)]. The ligand L1 is particularly interesting, as it is a hemiaminal ether (usually considered to be unstable intermediates in the reactions of aldehydes and secondary amines in alcoholic solvents), and was found to be trapped in 11. Although 11-13 have identical tetranuclear basic structures (with the rare simultaneous end-on and end-to-end bridges between two neighbouring metal-ions, Scheme 2) and extend in one-dimension. However, 13 is differently organized from the other two complexes. For 14, the bridging structure among the peripheral copper(II) ions changes to double end-on (Scheme 2), and the resulting structure extends in two dimensions. However, with L5, metal to ligand ratio is 9:4 (under similar conditions and initial molar proportions of the components) in 15, which can be seen as two different fragments: [Cu4(L5)4(N3)6]2+ and [Cu5(N3)12]2- linked alternately to give an overall 1D structure. HL6 and HL7 have one ionisable phenolic group that replaces one azido anion and generates two pockets for the metal atoms. These monoanionic ligands give tetranuclear complexes (16 and 17) with basic structures resembling (Scheme 2) to 11-14. While 17 is 1D in nature, two coordinated water molecules prevent the structure of 16 to grow and results in a discrete cluster. The variable temperature magnetic properties of these complexes were thoroughly analyzed through experimental and theoretical (DFT) studies. CHAPTER 4 reports the use of a pyridyl substituted propanediolate ligand in the assembly of two novel 1D heterometallic complexes: [Mn3Na(L)4(CH3CO2)(MeOH)2](ClO4)2∙3H2O (18) and [Mn3Na(L)4(CH3CH2CO2)(MeOH)2](ClO4)2∙2MeOH∙H2O (19) [LH2 = 2-methyl-2-(2-pyridyl)propane-1,3-diol, Scheme 3]; both featuring octahedral MnIV ions linked alternately to one trigonal prismatic MnII ion and even more interestingly to one trigonal prismatic NaI ion (Scheme 3). The complexes are essentially identical in structure and magnetic behavior, showing a weak ferromagnetic interaction among the neighboring manganese ions. DFT studies on a model complex supports the S = 11/2 ground spin state, deduced from dc and ac susceptibility measurements. CHAPTER 5 illustrates the use of a few dicarboxylates as potential bridging ligands to assemble tri- and hexanuclear MnIII-clusters. With the salicylaldoximate (salox) as the [MnIII3O(salox)3]+, triangle-generating moiety and keeping the reaction conditions (solvent, base, reaction time and crystallization process) identical, four new extended complexes that differ both in their basic and higher dimensional organizations are reported. When 1,3-phenylenediacetate (phda) is used (in EtOH), in the resulting complex [MnIII6O2(salox)6(EtOH)4(phda)]n∙(saloxH2)n∙(2H2O)n (20), a single type of MnIII6 clusters are linked by the dicarboxylate (interestingly the complex crystallizes with uncoordinated saloxH2 molecules). However, when two differently substituted isophthalate linkers (5-iodoisophthalate and 5-azidoisophthalate) are used, two almost identical complexes [MnIII6O2(salox)6(MeOH)5(5-I-isoph)]n∙(3MeOH)n (21) and [MnIII6O2(salox)6(MeOH)4(H2O)(5-N3-isoph)]n∙(4MeOH)n (22) are isolated, with two different types of Mn6 clusters (Scheme 4) linked alternately in one dimension. More interestingly, use of another substituted isophthalate (5-nitroisophthalate) produced a heteronuclear complex [MnIII3NaO(salox)3(MeOH)4(5-NO2-isoph)]n∙(MeOH)n(H2O)n (23) with only MnIII3 triangles as the basic cluster assembled in two dimensions. Temperature and field dependent dc and ac susceptibility measurements show that the complexes 20-22 behave as non-interacting single molecule magnets with ground spin state S = 4. Complex 23 is dominantly antiferromagnetic with a ground spin state S = 2. The magnetic behaviours of these complexes are also supported by theoretical calculations (DFT) on models generated from the crystal structures.

Nesta tese são abordadas as propriedades químicas e espectroscópicas dos clusters de Au-M, onde M = Pd ou Pt com o ligante PPh3. A nuclearidade destes compostos varia de 7: [Pd(PPh3)(AuPPh3)6](PF6)2 a 9: [Pt(AuPPh3)8](NO3)2 tendo ambos 16 e- de valência, segundo a contagem de elétrons estabelecida por Mingos. Um terceiro cluster preparado a partir dos precursores [pd(pPh3)(AuPPh3)6]2+ e Sn2+ também apresentou nuclearidade 9, com contagem de 16 e- de valência e possível fórmula molecular: [pd(SnCl3)2(AuPPh3)6](NO3)2. Foi empreendido um estudo da solubilidade e estabilidade do cluster [pd(SnCl3)2(AuPPh3)6](NO3)2 nos detergentes CTAB ou NaLS em meio aquoso, sendo esta solubilidade monitorada utilizando um espectrofotômetro UV/vis. A caracterização dos compostos foi feita com o uso das técnicas termogravimétricas (TGAlDTG) e espectroscópicas RMN, IV, UV-vis, Raman, FABMS e difração de raios-X. A estrutura cristalina e molecular do cluster [Pd(PPh3)(AuPPh3)6](PF6)2, obtida por difração de raios-X, mostra que o sistema cristalino é o triclínico com grupo espacial P1 com a = 17,138 (3) Å, b = 27,263 (5) Å, c = 27,543 (6) Å, α = 101,70 (3) °, β= 105,80 (3) °, γ = 90,19 (3) °, T= 273°C, Z = 4, V= 12 102 Å3, R = 0,1149 e Rw = 0,2669 para 23 620 observações e radiação Mo Kα. Testes catalíticos realizados com o cluster [Pd(PPh3)(AuPPh3)6](NO3)2 na reação de hidrogenação, à alta pressão, do 1,5-COD foram bem sucedidos. / This work presents the chemistry and spectroscopic properties of phosphine-stabilized, M-centered Au cluster compounds where M = palladium or platinum. The nuclearity of the clusters ranges from 7: [Pd(PPh3)(AuPPh3) 6](PF6)2 to 9: [Pt(AuPPh3)8](NO3)2 both having 16-electrons in terms of the electron counting model established by Mingos. A third cluster prepared from [Pd(PPh3)(AnPPh3)6]2+ and Sn2r presents nuclearity 9 too and 16-electrons and the molecular formula apparently is [pd(SnCl3)2(AuPPh3)6](NO3)2. The solubility study of the cluster [pd(SnCl3)2(AuPPh3)6](NO3)2 was made using CTAB or NaLS and the results obtained are based on UV/vis analysis. Nuclear magnetic resonance (NMR), fast atom bombardment mass (FABMS), UV-visible, Infrared, TGA/DTG thermogravimetric and a single-crystal X-ray crystallographic analysis of the clusters were of great utility for the characterization of these compounds. The crystal data for [pd(pPh3)(AuPPh3)6 (PF6)2 are as follows: triclinic P1, a = 17,138 (3) Å, b = 27,263 (5) Å, c = 27,543 (6) Å, α = 101,70 (3) °, ¨β = 105,80 (3) °, γ = 90,19 (3) °, T= 273°C, Z = 4, V= 12 102 Å3, R = 0,1149 and Rw = 0,2669 for 23 620 observed reflections and Mo Kα radiation. The catalytic application of the cluster [Pd(PPh3)(AuPPh3)6](NO3)2 in the hydrogenation of 1,5-COD brought promising results when the reaction is developed at high pressure.

Les systèmes moléculaires à base de cations lanthanides luminescents possèdent des propriétés photophysiques très intéressantes pour les applications en bioimagerie optique (résistance au photoblanchiment, bandes d’émission fines, temps de vie de luminescence longs). La lumière émise peut couvrir une large gamme spectrale, selon le cation lanthanide choisi. Cependant, les lanthanides ont des coefficients d’extinction faibles. Il est donc nécessaire d’utiliser une voie de sensibilisation indirecte - l’effet d’antenne, avec un chromophore placé à proximité du lanthanide. De plus, afin d’amplifier le signal émis, plusieurs cations métalliques peuvent être introduits dans la molécule. Dans cette thèse, nous avons cherché à développer de nouveaux agents potentiels d’imagerie à base de systèmes polynucléaires de lanthanides. Notre objectif a été de programmer l’assemblage de complexes supramoléculaires tridimensionnels et d’améliorer les propriétés optiques pour les applications biologiques. Pour ce faire, nous avons choisi d’employer des ligands tripodaux composés d’une ancre centrale triaminotriptycène et de trois bras possédant les sites coordinants. Ces ligands ont ensuite été modifiés de façon à optimiser les propriétés physico-chimiques. Par ailleurs, la synthèse de nouvelles plateformes centrales a été également effectuée afin de poursuivre leur développement dans le futur. La synthèse et la caractérisation de ligands tripodaux L1 et L2 et de leurs complexes avec des lanthanides ont été réalisées. Des études détaillées de spéciations avec les ligands L1 et L2 ont permis de démontrer la stabilité thermodynamique des systèmes tétranucléaires formés en préférence avec les lanthanides légers. Des études spectroscopiques ont caractérisé leur luminescence dans le visible et dans le proche infrarouge. D’autre part, nous avons préparé et caractérisé des nouveaux composés en combinant un chromophore porphyrinique et des récepteurs complexant les lanthanides. Ces sondes bimodales peuvent trouver une application dans l’imagerie et la thérapie photodynamique. / Molecular systems based on luminescent lanthanide cations have very valuable photo-physical properties for applications in optical bioimaging (resistance to photobleaching, sharp emission bands, and longue luminescence lifetimes). The emitted light can cover a wide spectral range, according to the chosen lanthanide cation. However, the lanthanides have low extinction coefficients and must be sensitized indirectly via the antenna effect by using a chromophore located in proximity. The luminescence intensity per molecule can be also increased by accommodating several lanthanides within a single compound. In this thesis, we report on the development of new potential imaging agents based on polynuclear systems with lanthanides. The main goal was to program supramolecular well-defined tridimensional complexes in order to enhance their optical properties for biological applications. To do this, we have chosen to employ tripodal ligands composed of a central triaminotriptycene anchor and three arms with coordinating sites. Moreover, these ligands have been functionalized to improve their physicochemical properties. In view of future developments, the synthesis of new central platforms was also performed. The synthesis and characterization of tripodal ligands L1 and L2 and their complexes with lanthanides were carried out. Detailed speciation studies with L1 and L2 show a high thermodynamic stability of tetranuclear systems formed preferably with lighter lanthanides. In addition, spectroscopic studies reveal that the sensitization of luminescence is achieved in the visible as well as in the near infrared. Furthermore, we have prepared and characterized novel compounds by combining a porphyrin chromophore and a receptor for lanthanide complexation. These bimodal probes may find applications in imaging and in photodynamic therapy.