Local control of tumours by radiotherapy may fail due to the presence of regions of hypoxic cells. Radiosensitizers, such as nitroimidazoles, enhance killing of the resistant cells by ionizing radiation. However, dose limiting side-effects have prevented the attainment of maximum sensitization. The successful chemotherapeutic drug, cis-diamminedichloroplatinum(II) (cis-DDP), and analogues show moderate radiosensitizing effects, possibly because of binding to DNA. A rationale is then to use the DNA binding property of a metal to carry a sensitizer to the target of radiation damage, DNA, thereby improving the radiosensitizing effect while reducing the toxic side-effects of nitroimidazoles. The complex cis-RuCI₂(dmso)₄ was used as a precursor for synthesis of Ru(II)-nitroimidazole complexes because of its anti-tumour and DNA binding activities. A series of Ru(II) complexes of formulation RuCI₂(dmso)₂Ln, where dmso is S-bonded dimethyl sulphoxide, L = a nitroimidazole, and n=1 or 2, has been synthesized and characterized, and their toxicities and radiosensitizing abilities examined in vitro. When L = 2-nitroimidazole or a substituted-2-nitroimidazole, n = 2, but the nitroimidazole ligands dissociate in aqueous medium. With L = the 5-nitroimidazole, metronidazole, n=2, the sensitizing ability of the six-coordinate cis complex was disappointing with sensitizer enhancement ratio (SER) of 1.2 in hypoxic Chinese hamster ovary (CHO) cells. A series of 4-nitroimidazoles ligands was then studied. With L = 4-nitroimidazole (4-NO₂-Im), 1-(1' -aziridinyl-2' -propanol)-2-methyl-4-nitroimidazole (RSU-1170), 2-(1,2-dimethyl-4-nitroimidazolyl)-2-aminoethanol (RSU-3083), and 1-methyl-4-nitro-5-phenoxyimidazole (RSU-3100), n=2 and the six coordinate complexes appear to be of all cis geometry. The NMe-4-NO₂-Im ligand (n=1) chelates through the imidazole-N and the oxygen of NO₂ group as evidenced from spectroscopic data. Coordination via the nitrito group is uncommon and other examples involving nitroimidazole ligands have not been reported. For the 1-methyl-5-(2'-thioimidazolyl)-4-nitroimidazole (RSU-3159) ligand (n=1), binding to Ru occurs through the thioether and chelation may occur through the imidazole-NCH₃. In this series of Ru(II)-4-nitroimidazole complexes studied, RuC1₂(dmso)₂-NO₂-Im)₂, 5, was the most effective radiosensitizer (SER = 1.6 at 200 ,μM) and is better than the clinically used misonidazole (SER = 1.3 at 200 μM). In addition, 5 did not sensitize oxic CHO cells. Other Ru-N-substituted-4-nitroimidazole complexes gave SER values of 1.1-1.4 at 100-200 μM. Complex 5 also produced a dose-dependent increase in genotoxic activity (as measured by the in vitro induction of chromosome aberrations in CHO cells), which is similar to that of misonidazole but much less than that of c/s-DDP. Two changes in ancillary ligands and geometry of complexes were also examined: replacement of (i) dmso by tmso (tetramethylene sulphoxide), (ii) C1⁻ by Br⁻. The Ru-nitroimidazole complexes were synthesized from the precursors RuCl₂(tmso)₄ and trans-RuBr₂(dmso)₄. In this series of complexes, only RuCl₂(tmso)₂(4-NO₂-Im)₂, 15, and RuCl₂(tmso)₂(SR-2508), 18, have significantly higher SER values (1.6 and 1.5, respectively) than their corresponding nitroimidazole ligands. The tmso complexes of 2-NO₂-Im derivatives were more stable than the dmso series in aqueous solution with respect to the dissociation of the nitroimidazole ligands, which might be due to the improved lipophilicity of tmso complexes. Complex 18. is suggested to be penta-coordinated from XPS and ir data. The RuBr₂(dmso)₂(4-NO₂-Im)₂ was a less effective sensitizer (SER = 1.3 at 200 μM) than the dichloro analogue which may result from different geometrical structures or different behaviour in aqueous solution chemistry. The enhanced radiosensitizing effect over the corresponding free nitroimidazole ligand observed for complexes 5, 15 and 18 may depend on: (a) the metal's ability to target the sensitizer to DNA; complex 5 does bind to DNA, dissociation of C1⁻ perhaps facilitating the reaction; (b) the increase in reduction potential or (c) an increase in lipophilicity of the nitroimidazole ligand on coordination. However, the enhanced radiosensitization does not result from depletion of non-protein thiols. In the present study, the Ru complexes are less toxic than their corresponding nitroimiazole ligands in vitro. The radiosensitization and toxicity of the complexes 5, 15 and 18 are better than those of the free nitroimidazole ligands and the clinically used radiosensitizer, misonidazole. The data encourage further investigations of the use of transition metal complexes as radiosensitizers to combat the hypoxic tumour cells. [Formula Omitted] / Science, Faculty of / Chemistry, Department of / Graduate

M.Tech. (Engineering: Metallurgy) / The aim of the study was to determine the slurry erosion-corrosion rates as well as electrochemical corrosion rates of WC-Fe-Ru coatings that were thermally coated using a plasma transferred arc method. The WC-Fe-Ru coatings used had different bulk Ru concentrations that varied from 0.7 to 4.1 wt% Ru. A slurry jet impingement erosion-corrosion test rig was used for the erosion-corrosion rate measurements, and an Autolab 302 potentiostat was used to measure the open circuit potential during a 12 hour exposure in the test solution, as well as a potentiodynamic scan to determine the corrosion potential...

Computational techniques were employed to investigate pathways that would improve the properties and characteristics of transition metal (i.e., ruthenium) catalysts, and to explore their mechanisms. The studied catalytic pathways are particularly relevant to catalytic hydroarylation of olefins. These processes involved the +2 to +3 oxidation of ruthenium and its effect on ruthenium-carbon bond strengths, carbon-hydrogen bond activation by 1,2-addition/reductive elimination pathways appropriate to catalytic hydrogen/deuterium exchange, and the possible intermediacy of highly coordinatively unsaturated (e.g., 14-electron) ruthenium complexes in catalysis. The calculations indicate a significant decrease in the Ru-CH3 homolytic bond dissociation enthalpy for the oxidation of TpRu(CO)(NCMe)(Me) to its RuIII cation through both reactant destabilization and product stabilization. This oxidation can thus lead to the olefin polymerization observed by Gunnoe and coworkers, since weak RuIII-C bonds would afford quick access to alkyl radical species. Calculations support the experimental proposal of a mechanism for catalytic hydrogen/deuterium exchange by a RuII-OH catalyst. Furthermore, calculational investigations reveal a probable pathway for the activation of C-H bonds that involves phosphine loss, 1,2-addition to the Ru-OH bond and then reversal of these steps with deuterium to incorporate it into the substrate. The presented results offer the indication for the net addition of aromatic C-H bonds across a RuII-OH bond in a process that although thermodynamically unfavorable is kinetically accessible. Calculations support experimental proposals as to the possibility of binding of weakly coordinating ligands such as dinitrogen, methylene chloride and fluorobenzene to the "14-electron" complex [(PCP)Ru(CO)]+ in preference to the formation of agostic Ru-H-C interactions. Reactions of [(PCP)Ru(CO)(1-ClCH2Cl)][BAr'4] with N2CHPh or phenylacetylene yielded conversions that are exothermic to both terminal carbenes and vinylidenes, respectively, and then bridging isomers of these by C-C bond formation resulting from insertion into the Ru-Cipso bond of the phenyl ring of PCP. The QM/MM and DFT calculations on full complexes [(PCP)(CO)Ru=(C)0,1=CHPh]+ and on small models [(PCP')(CO)Ru=(C)0,1=CH2]+, respectively, offered data supportive of the thermodynamic feasibility of the suggested experimental mechanisms and their proposed intermediates.

This thesis is based on the past three years of research work including synthesis, characterization of three series of iridium(III) complexes and one series of ruthenium(II) complexes, and their comparative bio-applications of DNA-binding, cell morphology, cytotoxicity, mitochondrial membrane potential, cellular uptake and distribution. Chapter 1 introduces the background and recent studies of transition-metal complexes as biosensors and anti-tumor medicines. Their structure related properties of cytotoxicities, cellular uptake and distributions were also discussed. In chapter 2, five iridium(III) complexes Ir4: [Ir(4-mpp)2DPPZ]+, Ir7: [Ir(4-mpp)2BDPPZ]+, Ir8: [Ir(4-mpp)2MDPPZ]+, Ir115: [Ir(pp)2DBDPPZ]+ and Ir139: [Ir(dpapp)2DBDPPZ]+ were synthesized and characterized. The crystals of complex Ir139 were successfully cultured and analyzed by X-ray crystallography. The HOMO and LUMO energy gaps of complexes Ir4, Ir7 and Ir8 were obtained. The smaller the energy gap is the larger the Stokes shift will be. The DNA binding properties of Ir4, Ir7 and Ir8 were studied to acquire their binding constants and quenching constants. All the five complexes were cultured with hepatocellular carcinoma cell (hep-G2) in different concentrations for cell morphologies and MTT assays. The IC50 values were calculated and the structure-activity relationship (SAR) was discussed. Properties of Ir115 and Ir139 for photodynamic therapy under the visible light were studied, and moderate light-enhanced cytotoxicities were discovered. The live and dead cell assay and mitochondrial transmembrane potential (ΔΨM) testing were performed and a similar cytotoxicity order to IC50 values was obtained. Some interesting interactions between complex and calcein or propidium iodide (PI) dye were observed and discussed. Cellular uptake and distribution assay showed that the fluorescence of iridium complex was closely related to its toxicity. The obvious cellular uptake at 4 ℃ indicated that all the complexes could transfer into cell through a passive transport mode of facilitated diffusion without the consumption of ATP. The greatest change in uptake intensity of Ir115 implied that the ATP could assist the transport of Ir115 at 37.5 ℃. The efficiency of uptake and distribution of complexes in paraformaldehyde (PFA) fixed cells was found to be strictly related to their size and the hydrophobicity. The rigidity of dipyrido[3,2-a:2',3'-c]phenazine based bipyridine ligands in this chapter contributed to the main cytotoxcities of those iridium complexes. Most of the iridium complexes in chapter 2 have similar structures to their classic ruthenium analogues while their activities have largely improved due to the higher cellular uptake and more biocompatibility. Chapter 3 presented five iridium complexes with rotatable 1H-imidazo [4,5-f] [1,10] (phenanthroline) based bipyridine ligands, which are Ir79: [Ir(pp)2MTPIP]+, Ir80: [Ir(pp)2EIPP]+, Ir116: [Ir(piq)2APIP]+, Ir119: [Ir(piq)2PPIP]+ and Ir134: [Ir(iqdpba)2PPIP]+. Cell morphology and proliferation assay, MTT assay indicated that most of them were not quite toxic for hep-G2 cell lines except for Ir116 which contained an amino group and was assumed to be very active to the carboxyl group in the protein residues in cells. Under the irradiation of visible light, Ir80 and the Ir119 were found to be quite photo-toxic with the light IC50 value of 8.08 μM and 6.14 μM respectively. They could become the potential candidates for the promising drugs of photo-dynamic therapy. The cytotoxicities of those five complexes were further investigated by the live and dead assay using calcein AM (acetoxymethyl) and propidium iodide (PI) double stain method. JC-1 aggregates observation and analysis in the mitochondrial transmembrane potential (ΔΨM) testing proved the lower cytotoxicities of those five complexes than those in chapter 2. Fluorescence and cytotoxicity relationship (FCR) was also uncovered in chapter 3 in which the stronger macromolecular binding to complex could lead to its higher fluorescence intensity. Without the metabolic activity and the assistance of ATP at low temperature of 4 ℃, little Ir80 and Ir134 were found in cells, and the moderate uptake for Ir79 and higher volume of Ir116 and Ir119 were detected. A novel strategy of cold-shock enhanced cellular uptake pathway was discovered in Ir119 and its cold-shock caused cytotoxicity would be further evaluated. The volumes of uptake for those complexes in paraformaldehyde fixed cells were all very low due to their higher hydrophilicity and lower structural rigidity than those in chapter 2. Chapter 4 reported the investigation of six iridium complexes of Ir105: [Ir(4-mpp)2CDYP]+, Ir107: [Ir(piq)2CDYP]+, Ir108: [Ir(3-mpp)2CDYP]+, Ir123: [Ir(4-mpp)2CDYMB]+, Ir125: [Ir(piq)2CDYMB]+ and Ir133: [Ir(dpapp)2CDYMB]+ with rotatable 5H-cyclopenta[2,1-b:3,4-b']dipyridin Schiff-base ligands. Most of them were rather toxic to hep-G2 cell lines from the MTT assay, cell morphology and proliferation assay due to the Schiff-base N^N ligands. Those rotatable Schiff-base ligands seemed to have more cytotoxicity than the flexible 1H-imidazo[4, 5-f] [1, 10](phenanthroline) ligands in chapter 3. The planar and rigid structure of piq C^N ligands in Ir107 and Ir125 were supposed to contribute to the highest cytotoxicity in chapter 4. The dead (red PI) to live (green calcein) cell area ratios and the ΔΨM assay were in accordance with the cytotoxocity sequence in MTT assay. Most of the complexes in chapter 4 demonstrated characteristics of one kind of programmed cell death (PCD), namely apoptosis and the typical features of another cell death mode of oncosis including cellular dwelling and cytoplasm vacuolation have been discovered from Hep-G2 cell lines in the incubation with Ir107. The JC-1 aggregates have disappeared when the two most toxic complexes Ir107 and Ir125 were cultured with the cells at 5 μmol/L, indicating the ΔΨM lost repidly under the damage of iridium complexes. All the complexes were distributed in the cellular nuclei when the incubation time reached 120 minutes at the concentration of 20 and 40 μmol/L. The positive correlation in the fluorescence and cytotoxicity relationship (FCR) were also discovered in chapter 4. The luminescence intensity sequence of the complexes from the cellular uptake and distribution has almost the same order as the previous toxicity results. The two most toxic complexes of Ir107 and Ir125 were found to have the two highest fluorescent intensities inside cells at 4 ℃. Most complexes in this chapter could easily distribute in the fixed cellular nuclei except for Ir125 and Ir133 owing to their large and hydrophobic structures. Generally, the uptake of complexes in paraformaldehyde fixed cells was higher than the live cells at 4 ℃ according to their passive transport mode. Although the simple Schiff base ligands of CDYP and CDYMB in this chapter were rotatable and flexible similar to the 1H-imidazo[4, 5-f][1, 10](phenanthroline) based bipyridine ligands in chapter 3, the cytotoxicities of complexes were much higher than those in chapter 3. The former chapters implied that effective uptake of complexes in nuclei were the results of the cytotoxicities which damaged the integrity of nuclear envelope and leaked into the nucleoplasm. We assumed that there could be another explanation in chapter 4 that the complexes transferred into the nuclei through the nuclear pore on the nuclear envelope and accumulated in the nucleolus, and therefore, triggered the apoptosis of cells. This kind of evidence was discovered for the two most toxic complexes Ir107 and Ir125 that could enter into cellular nuclei when the cell looked quite healthy. There would be another possiblilty that the Schiff base could interrupt the function of intracellular hydrolase enzymes. Chapter 5 compared the properties of five ruthenium(II) complexes of Ru2: [Ru(bpy)2DBDPPZ]2+, Ru7: [Ru(bpy)2MTPIP]2+, Ru8: [Ru(bpy)2EIPP]2+, Ru15: [Ru(phen)2BPDC]2+ and Ru24: [Ru(phen)2CDYMB]2+ with the ligand DBDPPZ from chapter 2, MTPIP and EIPP from chapter 3, CDYMB from chapter 4 and BPDC with two carboxyl groups. Those two positively charged ruthenium complexes indicated very low cytotoxicities from the cell morphology assay and MTT assay. No typical features of cellular apoptosis such as round and shrank cells were observed. However, the light IC50 value of Ru8 was excitingly obtained to be 2.33 μM upon the irradiation of 465 nm which was found to be one of the most promising drugs for photodynamic therapy (PDT) in his thesis. Charge and property relationship (CPR) was discovered to be the most decisive factor in the cytotoxicities of iridium and ruthenium complexes in this thesis which was also supported by a few of the independent literature papers mentioning high cytotoxicity of one positively charged ruthenium complex or low toxicity of two positively charged iridium complex. The DBDPPZ and CDYMB ligands in the ruthenium complexes Ru2 and Ru24 did not add into their cytotoxicity but those ligands greatly enhanced the toxicities of iridium complexes. The calculation of both area and number ratios of dead to live cells stained by the PI and calcein dyes indicated the lowest dark cytotoxicity among the ruthenium complexes could be Ru8 while the Ru24 and Ru7 were more toxic than others. Active JC-1 aggregates were maintained in the cell mitochondria and did not greatly diminish with the increasing concentration of ruthenium complexes. The two positive charges were found to play the important role in the poor cellular uptake of all the ruthenium complexes and the large size of phen ligand further prevented the uptake of Ru24 and reduced its toxicity. The Ru2, Ru7 and Ru8 were found to distribute in fixed cells with much higher luminescence intensities than their corresponding iridium complexes of Ir115, Ir79 and Ir80 with the same N^N ligand respectively which were assigned to be the two positive charges in those ruthenium complexes. The facilitated diffusion was found to be the main passive transport for the five ruthenium complexes in HepG2 cells at 4 ℃ when the ATP functions were considered to be largely inhibited. The low temperature cellular uptake has the similar trend of the cytotoxicities of the five complexes, indicating the structures of complexes were decisive in the process of facilitated diffusion. The enormous difference of cellular uptake and distribution in the fixes cells remind us the normal protocol before the cell-image pictures of fluorescence inverse microscopes (FIM) or confocal laser scanning microscope (CLSM) should be cancelled or very cautiously handled when the luminescent metal complexes were applied. In chapter 6, the further structure-activity relationship (SAR) was discussed based on the different C^N, N^N ligands and metal cores from the previous chapters. The overall research scheme, results and significance were summarized. Highlights were listed and future research plan was also proposed. At last, Chapter 7 described briefly the experiment protocols and supplementary information for the former chapters.

Olefin metathesis is arguably the most versatile catalytic route yet developed for the assembly of carbon-carbon bonds. Metathesis methodologies are attractive from both synthetic and ecological standpoints, because they employ unactivated double bonds. This reduces the total number of synthetic steps, and the associated generation of chemical wastes. The drive to deploy olefin metathesis in highly demanding contexts, including pharmaceutical manufacturing and chemical biology, puts severe pressure on catalyst lifetime and productivity. Understanding the relevant decomposition pathways is critical to achieve essential performance goals, and to enable informed catalyst redesign. This thesis work expands on significant prior advances that identified and quantified critical decomposition pathways for ruthenium catalysts stabilized by N-heterocyclic carbene (NHC) ligands. Because pristine catalyst materials are essential for mechanistic study, it focuses first on methods aimed at improving efficiency and purity in catalyst synthesis. Merrifield iodide resins were shown to function as efficient, selective phosphine scavengers in the production of clean second-generation catalysts from PCy3- stabilized precursors. The thesis then turns to mechanistic examination of decomposition pathways that underlie success and failure for leading NHC catalysts, for comparison with a new family of catalysts stabilized by cyclic (alkyl)(amino) carbene (CAAC) ligands. These represent the first in-depth mechanistic studies of the CAAC catalysts, which have attracted much attention for their breakthrough productivities in challenging metathesis reactions. The remarkable productivity of the CAAC catalysts is shown to originate in their resistance to decomposition of the key metallacyclobutane intermediate via b-elimination, and (to a lesser extent) in their resistance to attack by nucleophiles and Bronsted bases. Importantly, however, they are more susceptible to bimolecular decomposition. The latter behaviour, as well as their resistance to b-elimination, is traced to the strong trans influence of the CAACs relative to NHC ligands. This insight significantly advances our understanding of the fundamental properties governing both productivity and decomposition. Finally, two new catalysts are developed, building on the principle that nucleophilic stabilizing ligands should be avoided in the precatalysts. In the first of these complexes, an o-dianiline ligand is employed to stabilize the precatalyst. This flexible, H-bonding chelate serves the further purpose of accelerating macrocyclization of flexible dienes that bear polar functionalities. As its H-bonding capacity also increases its sensitivity to trace water, however, an alternative catalyst architecture was pursued. The latter consists of a dimer bearing bulky Ru-indenylidene centers, in which a dative bond from a bridging chloride affords the fifth ligand essential to stabilize the precatalyst.

Orientador: Valdemiro Pereira de Carvalho-Junior / Banca: Andrelson Wellington Rinaldi / Banca: Sérgio Antônio Marques de Lima / Resumo: A investigação de sistemas catalíticos duais capazes de mediar as reações de polimerização por abertura de anel via metátese (ROMP) e de polimerização radicalar por transferência de átomo (ATRP) simultaneamente é de grande interesse e importância na obtenção de novos materiais com potencial aplicação. Neste estudo, complexos de rutênio(II) inéditos coordenados a diferentes aminas cíclicas (pirrolidina, piperidina e peridroazepina) foram sintetizados: [RuCl2(dppb)(pirrolidina)] (1), [RuCl2(dppb)(piperidina)] (2) e [RuCl2(dppb)(peridroazepina)] (3). Os complexos 1, 2 e 3 foram obtidos a partir da reação entre o complexo [RuCl2(dppb)(PPh3)] com a respectiva amina cíclica em acetona. Os complexos 1, 2 e 3 foram caracterizados por EPR, FTIR, UV-Vis, RMN de 31P e 1H e voltametria cíclica. Os complexos planejados foram avaliados como precursores catalíticos em reações de ROMP de norborneno (NBE). As sínteses de polinorborneno (poliNBE) via ROMP com os complexos 1, 2 e 3 como pré-catalisadores foram avaliadas sob condições de reação ([EDA]/[Ru] = 28 (5 µL), [NBE]/[Ru] = 5000, variando o tempo de 10 a 60 minutos a 25 e 50 ºC. A atividade catalítica dos complexos em ROMP de NBE demonstrou a seguinte ordem de reatividade: 3 > 2 > 1, a qual está relacionada ao maior sinergismo aminaRuolefina. A polimerização de MMA via ATRP foi conduzida usando os complexos 1, 2 e 3 na presença de etil-α-bromoisobutirato (EBiB) como iniciador. Os testes catalíticos foram avaliados em função do... / Abstract: The investigation of dual catalytic systems able to mediate simultaneously ringopening metathesis polymerization (ROMP) and atom-transfer radical polymerization (ATRP) reactions are of great interest and importance in obtaining new materials with potential for application. In the study, a series of three amineruthenium(II) complexes (amine = pyrrolidine, piperidine and perhydroazepine) was synthesized: [RuCl2(dppb)(pirrolidina)] (1), [RuCl2(dppb)(piperidina)] (2) and [RuCl2(dppb)(peridroazepina)] (3). Complexes 1, 2 and 3 were synthesized from the reaction between the [RuCl2(dppb)(PPh3)] complex and the respective amine in acetone. Complexes 1, 2 and 3 were characterized by EPR, FTIR, UV-Vis, 31P and 1H NMR, and cyclic voltammetry. The catalytic activity of complexes was evaluated in ROMP of norbornene (NBE). The synthesis of polynorbornene via ROMP using complexes 1, 2 and 3 as pre-catalysts was evaluated under reaction conditions of [EDA]/[Ru] = 28 (5 μL), [NBE]/[Ru] = 5000 at 25 and 50 °C as a function of time (10 to 60 min). The catalytic activity of the complexes for ROMP of NBE showed the following order of reactivity: 3 > 2 > 1, which is related to the greater -donation from the amine. The polymerization of MMA via ATRP was conducted using the complexes 1, 2 e 3 in the presence of ethyl 2-bromoisobutyrate (EBiB) as the initiator. All tests were made using the molar ratio [MMA]/[EBiB]/[Ru] = 1000/2/1 and conducted at 85 °C. For complex 3, molecular weights increased linearly with conversion, however, the experimental molecular weights were higher than the theoretical ones / Mestre

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23363号 / 理博第4734号 / 新制||理||1679(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 北川 宏, 教授 吉村 一良, 教授 竹腰 清乃理 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Thesis(M.Sc. (Chemistry)) -- University of Limpopo, 2019 / Imidazolyl-ethanamine Schiff base ligands of the N^N type were prepared by condensation reaction of histamine dihydrochloride with para-substituted aldehyde derivatives to yield: (E)-N-benzylidene-2-(1H-imidazol-4-yl)ethanamine 119a, 4-((E)(2-(1H-imidazol-4-yl)ethylimino)methyl)phenol 119b, E)-N-(4-fluorobenzylidene)-2(1H-imidazol-4-yl)ethanamine 119c and (E)-N-(4-nitrobenzylidene)-2-(1H-imidazol-4yl)ethanamine 119d, which were characterised by 1H and 13C-NMR, FTIR specroscopy and HRMS. 2D-NMR experiments (1H-1H COSY and 2D-HMBC) for representative ligand 119b were performed to qualify success in the condensation reaction. An attempted reaction to coordinate Schiff base ligand 119c to zinc chloride was carried out in an NMR tube and traces of the product were observed between 12 and 24 h monitoring using 1H-NMR. Iodine promoted cyclocondensation reaction of anthranilamide and para-substituted aldehyde derivatives afforded 2-aryl-quinazolin4(3H)-ones 120a-e and subsequent chloro-aromatisation reaction in SOCl2 afforded electrophilic C4-(Cl) 2-aryl-4-chloro-quinazolines 121a-e and the compounds were characterised by 1H and 13C-NMR and FTIR spectroscopic techniques. The 2-aryl-4chloro-quinazolines served as prerequisites for de-chloro amination on the C4-(Cl) position by 2-amino-3-nitropyridine to yield 2-aryl-N-(3-nitropyridin-2-yl)quinazolin-4amine derivatives 123a-e in good yield and the derivatives were characterised by 1H and 13C-NMR, FTIR and HRMS spectroscopic techniques. The C4-(Cl) position further allowed for Sonogashira cross-coupling with ethynylpyridine to yield 2-aryl-4(ethynylpyridine)quinazoline derivatives 125a-e which were characterised by 1H and 13C-NMR, FTIR and HRMS spectroscopic techniques. The 2-aryl-4(ethynylpyridine)quinazoline served as ligands for coordination to monomeric pcymene ruthenium(ll) which yielded (ɳ6-p-cymene)RuCl2-2-aryl-4(ethynylpyridine)quinazoline derivatives 126a-e in good yield. Compounds 126a-e were characterised by 1H and 13C-NMR, FTIR and HRMS spectroscopic techniques. 2D-HMBC NMR of representative ligands 126c and 126e showed long range couplings from 1JCH to 9JCH and this was confirmed by coordination induced shifts (CIS) ranging from 1 ppm to 11 ppm. Compounds 119a-d, 123a-e and 125a-e were inductively docked into the active receptors of tyrosine kinase (PDB:2SRC), glutamine synthetase (PDB:1HTO) and oxidoreductase (PDB:3F8P). The docking scores obtained gave hits ranging from -5 to -10 Kcal/mol. Compounds 119a-d, 121a-e, 123a-e, 125a-e and 126a-e were assayed employing the broth-dilution method which gave promising anti-Mycobaterium tuberculosis activity. Compound 125e gave good activity of <0.244 µg/mL over 7 day and 14 day sampling. Coordination of ligands 125a-e to Ru(ll) group resulted in loss of activity, notably for ligand 125e. / NRF and Sasol Inzalo Bursary

This thesis is based on the past three years of research work including synthesis, characterization of three series of iridium(III) complexes and one series of ruthenium(II) complexes, and their comparative bio-applications of DNA-binding, cell morphology, cytotoxicity, mitochondrial membrane potential, cellular uptake and distribution. Chapter 1 introduces the background and recent studies of transition-metal complexes as biosensors and anti-tumor medicines. Their structure related properties of cytotoxicities, cellular uptake and distributions were also discussed. In chapter 2, five iridium(III) complexes Ir4: [Ir(4-mpp)2DPPZ]+, Ir7: [Ir(4-mpp)2BDPPZ]+, Ir8: [Ir(4-mpp)2MDPPZ]+, Ir115: [Ir(pp)2DBDPPZ]+ and Ir139: [Ir(dpapp)2DBDPPZ]+ were synthesized and characterized. The crystals of complex Ir139 were successfully cultured and analyzed by X-ray crystallography. The HOMO and LUMO energy gaps of complexes Ir4, Ir7 and Ir8 were obtained. The smaller the energy gap is the larger the Stokes shift will be. The DNA binding properties of Ir4, Ir7 and Ir8 were studied to acquire their binding constants and quenching constants. All the five complexes were cultured with hepatocellular carcinoma cell (hep-G2) in different concentrations for cell morphologies and MTT assays. The IC50 values were calculated and the structure-activity relationship (SAR) was discussed. Properties of Ir115 and Ir139 for photodynamic therapy under the visible light were studied, and moderate light-enhanced cytotoxicities were discovered. The live and dead cell assay and mitochondrial transmembrane potential (ΔΨM) testing were performed and a similar cytotoxicity order to IC50 values was obtained. Some interesting interactions between complex and calcein or propidium iodide (PI) dye were observed and discussed. Cellular uptake and distribution assay showed that the fluorescence of iridium complex was closely related to its toxicity. The obvious cellular uptake at 4 ℃ indicated that all the complexes could transfer into cell through a passive transport mode of facilitated diffusion without the consumption of ATP. The greatest change in uptake intensity of Ir115 implied that the ATP could assist the transport of Ir115 at 37.5 ℃. The efficiency of uptake and distribution of complexes in paraformaldehyde (PFA) fixed cells was found to be strictly related to their size and the hydrophobicity. The rigidity of dipyrido[3,​2-​a:2',​3'-​c]phenazine based bipyridine ligands in this chapter contributed to the main cytotoxcities of those iridium complexes. Most of the iridium complexes in chapter 2 have similar structures to their classic ruthenium analogues while their activities have largely improved due to the higher cellular uptake and more biocompatibility. Chapter 3 presented five iridium complexes with rotatable 1H-imidazo [4,5-f] [1,10] (phenanthroline) based bipyridine ligands, which are Ir79: [Ir(pp)2MTPIP]+, Ir80: [Ir(pp)2EIPP]+, Ir116: [Ir(piq)2APIP]+, Ir119: [Ir(piq)2PPIP]+ and Ir134: [Ir(iqdpba)2PPIP]+. Cell morphology and proliferation assay, MTT assay indicated that most of them were not quite toxic for hep-G2 cell lines except for Ir116 which contained an amino group and was assumed to be very active to the carboxyl group in the protein residues in cells. Under the irradiation of visible light, Ir80 and the Ir119 were found to be quite photo-toxic with the light IC50 value of 8.08 μM and 6.14 μM respectively. They could become the potential candidates for the promising drugs of photo-dynamic therapy. The cytotoxicities of those five complexes were further investigated by the live and dead assay using calcein AM (acetoxymethyl) and propidium iodide (PI) double stain method. JC-1 aggregates observation and analysis in the mitochondrial transmembrane potential (ΔΨM) testing proved the lower cytotoxicities of those five complexes than those in chapter 2. Fluorescence and cytotoxicity relationship (FCR) was also uncovered in chapter 3 in which the stronger macromolecular binding to complex could lead to its higher fluorescence intensity. Without the metabolic activity and the assistance of ATP at low temperature of 4 ℃, little Ir80 and Ir134 were found in cells, and the moderate uptake for Ir79 and higher volume of Ir116 and Ir119 were detected. A novel strategy of cold-shock enhanced cellular uptake pathway was discovered in Ir119 and its cold-shock caused cytotoxicity would be further evaluated. The volumes of uptake for those complexes in paraformaldehyde fixed cells were all very low due to their higher hydrophilicity and lower structural rigidity than those in chapter 2. Chapter 4 reported the investigation of six iridium complexes of Ir105: [Ir(4-mpp)2CDYP]+, Ir107: [Ir(piq)2CDYP]+, Ir108: [Ir(3-mpp)2CDYP]+, Ir123: [Ir(4-mpp)2CDYMB]+, Ir125: [Ir(piq)2CDYMB]+ and Ir133: [Ir(dpapp)2CDYMB]+ with rotatable 5H-cyclopenta[2,1-b:3,4-b']dipyridin Schiff-base ligands. Most of them were rather toxic to hep-G2 cell lines from the MTT assay, cell morphology and proliferation assay due to the Schiff-base N^N ligands. Those rotatable Schiff-base ligands seemed to have more cytotoxicity than the flexible 1H-imidazo[4, 5-f] [1, 10](phenanthroline) ligands in chapter 3. The planar and rigid structure of piq C^N ligands in Ir107 and Ir125 were supposed to contribute to the highest cytotoxicity in chapter 4. The dead (red PI) to live (green calcein) cell area ratios and the ΔΨM assay were in accordance with the cytotoxocity sequence in MTT assay. Most of the complexes in chapter 4 demonstrated characteristics of one kind of programmed cell death (PCD), namely apoptosis and the typical features of another cell death mode of oncosis including cellular dwelling and cytoplasm vacuolation have been discovered from Hep-G2 cell lines in the incubation with Ir107. The JC-1 aggregates have disappeared when the two most toxic complexes Ir107 and Ir125 were cultured with the cells at 5 μmol/L, indicating the ΔΨM lost repidly under the damage of iridium complexes. All the complexes were distributed in the cellular nuclei when the incubation time reached 120 minutes at the concentration of 20 and 40 μmol/L. The positive correlation in the fluorescence and cytotoxicity relationship (FCR) were also discovered in chapter 4. The luminescence intensity sequence of the complexes from the cellular uptake and distribution has almost the same order as the previous toxicity results. The two most toxic complexes of Ir107 and Ir125 were found to have the two highest fluorescent intensities inside cells at 4 ℃. Most complexes in this chapter could easily distribute in the fixed cellular nuclei except for Ir125 and Ir133 owing to their large and hydrophobic structures. Generally, the uptake of complexes in paraformaldehyde fixed cells was higher than the live cells at 4 ℃ according to their passive transport mode. Although the simple Schiff base ligands of CDYP and CDYMB in this chapter were rotatable and flexible similar to the 1H-imidazo[4, 5-f][1, 10](phenanthroline) based bipyridine ligands in chapter 3, the cytotoxicities of complexes were much higher than those in chapter 3. The former chapters implied that effective uptake of complexes in nuclei were the results of the cytotoxicities which damaged the integrity of nuclear envelope and leaked into the nucleoplasm. We assumed that there could be another explanation in chapter 4 that the complexes transferred into the nuclei through the nuclear pore on the nuclear envelope and accumulated in the nucleolus, and therefore, triggered the apoptosis of cells. This kind of evidence was discovered for the two most toxic complexes Ir107 and Ir125 that could enter into cellular nuclei when the cell looked quite healthy. There would be another possiblilty that the Schiff base could interrupt the function of intracellular hydrolase enzymes. Chapter 5 compared the properties of five ruthenium(II) complexes of Ru2: [Ru(bpy)2DBDPPZ]2+, Ru7: [Ru(bpy)2MTPIP]2+, Ru8: [Ru(bpy)2EIPP]2+, Ru15: [Ru(phen)2BPDC]2+ and Ru24: [Ru(phen)2CDYMB]2+ with the ligand DBDPPZ from chapter 2, MTPIP and EIPP from chapter 3, CDYMB from chapter 4 and BPDC with two carboxyl groups. Those two positively charged ruthenium complexes indicated very low cytotoxicities from the cell morphology assay and MTT assay. No typical features of cellular apoptosis such as round and shrank cells were observed. However, the light IC50 value of Ru8 was excitingly obtained to be 2.33 μM upon the irradiation of 465 nm which was found to be one of the most promising drugs for photodynamic therapy (PDT) in his thesis. Charge and property relationship (CPR) was discovered to be the most decisive factor in the cytotoxicities of iridium and ruthenium complexes in this thesis which was also supported by a few of the independent literature papers mentioning high cytotoxicity of one positively charged ruthenium complex or low toxicity of two positively charged iridium complex. The DBDPPZ and CDYMB ligands in the ruthenium complexes Ru2 and Ru24 did not add into their cytotoxicity but those ligands greatly enhanced the toxicities of iridium complexes. The calculation of both area and number ratios of dead to live cells stained by the PI and calcein dyes indicated the lowest dark cytotoxicity among the ruthenium complexes could be Ru8 while the Ru24 and Ru7 were more toxic than others. Active JC-1 aggregates were maintained in the cell mitochondria and did not greatly diminish with the increasing concentration of ruthenium complexes. The two positive charges were found to play the important role in the poor cellular uptake of all the ruthenium complexes and the large size of phen ligand further prevented the uptake of Ru24 and reduced its toxicity. The Ru2, Ru7 and Ru8 were found to distribute in fixed cells with much higher luminescence intensities than their corresponding iridium complexes of Ir115, Ir79 and Ir80 with the same N^N ligand respectively which were assigned to be the two positive charges in those ruthenium complexes. The facilitated diffusion was found to be the main passive transport for the five ruthenium complexes in HepG2 cells at 4 ℃ when the ATP functions were considered to be largely inhibited. The low temperature cellular uptake has the similar trend of the cytotoxicities of the five complexes, indicating the structures of complexes were decisive in the process of facilitated diffusion. The enormous difference of cellular uptake and distribution in the fixes cells remind us the normal protocol before the cell-image pictures of fluorescence inverse microscopes (FIM) or confocal laser scanning microscope (CLSM) should be cancelled or very cautiously handled when the luminescent metal complexes were applied. In chapter 6, the further structure-activity relationship (SAR) was discussed based on the different C^N, N^N ligands and metal cores from the previous chapters. The overall research scheme, results and significance were summarized. Highlights were listed and future research plan was also proposed. At last, Chapter 7 described briefly the experiment protocols and supplementary information for the former chapters.

High-energy light was generated from lower-energy photons through an upconversion process using a mixture of a photosensitizer and an emitter. Factors that influence efficiency of the process were studied. Several ruthenium(II) complexes coordinated with bi- and polypyridyl ligands were prepared and used as photosensitizers. Anthracene and its derivatives were used as emitters. In each experiment, the upconversion sample was irradiated with a laser and the emission was monitored. The emission spectra exhibited upconversion (415-513 nm), scattering laser light (514 or 632.8 nm), and phosphorescence (>550 nm). The laser beam was positioned close to the edge of the sample cuvette to avoid a reduction in the upconversion emission caused by self absorption. Increases in laser power, photosensitizer concentration, or emitter concentration increased the upconversion intensity (Iu). Dissolved oxygen caused a minor decrease in Iu. Different photosensitizer and emitter derivatives were tested. Homoleptic ruthenium complexes were more effective photosensitizers with DPA as emitter than their heteroleptic analogues. Upconversion was detected in the [Ru(deab)3](PF6)2 (deab = 4,4'-bis(N,N-diethylamino)-2,2'-bipyridine) and DPA system using helium-neon (632.8 nm) and argon ion (514 nm) lasers, indicating the same process can occur whenever the photosensitizer absorbs the incident radiation. A detailed mechanism is proposed in which an excitation photon is absorbed by a sensitizer to produce an excited triplet state. Energy is transferred from sensitizer to emitter by collision, generating triplet excited emitter. Two emitter triplets annihilate to produce one highly excited singlet. This singlet emits the upconversion photon. The steady-state approximation is used to explore the upconversion and phosphorescence (Ip) intensities. Ip has a first order dependence on laser power, while Iu varies between first and second order. The variable power dependence of Iu occurs because of the competition between triplet-triplet annihilation and other decay pathways. Finally, (Iu/Ip2) is proportional to the second order of DPA concentration. These results generate a better understanding of the upconversion process and they will help to direct the work of others to enhance the efficiency of photonic devices. Practical applications of upconversion, such as the development of better photovoltaic cells, will be aided by the work described herein.