No / Several Ru-arene and Ir–Cp* complexes have been prepared incorporating (N,N), (N,O) and (O,O) coordinating bidentate ligands and have been found to be active against both HT-29 and MCF-7 cell lines. By incorporating a biologically active ligand into a metal complex the anti-cancer activity is increased.

Yes / A series of ruthenium and iridium complexes have been synthesized and characterized with 20 novel crystal structures discussed. The library of β-ketoiminato complexes has been shown to be active against MCF-7 (human breast carcinoma), HT-29 (human colon carcinoma), A2780 (human ovarian carcinoma), and A2780cis (cisplatin-resistant human ovarian carcinoma) cell lines, with selected complexes’ being more than three times as active as cisplatin against the A2780cis cell line. Selected complexes were also tested against the noncancerous ARPE-19 (retinal pigment epithelial cells) cell line, in order to evaluate the complexes selectivity for cancer cells. Complexes have also been shown to be highly active under hypoxic conditions, with the activities of some complexes increasing with a decrease in O2 concentration. The enzyme thioredoxin reductase is overexpressed in cancer cells, and complexes reported herein have the advantage of inhibiting this enzyme, with IC50 values measured in the nanomolar range. The anticancer activity of these complexes was further investigated to determine whether activity is due to effects on cellular growth or cell survival. The complexes were found to induce significant levels of cancer cell death by apoptosis with levels induced correlating closely with activity in chemosensitivity studies. As a possible cause of cell death, the ability of the complexes to induce damage to cellular DNA was also assessed. The complexes failed to induce double-strand DNA breaks or DNA cross-linking but induced significant levels of single-strand DNA breaks, indicating a mechanism of action different from that of cisplatin. / Lord RM, Hebden AJ, Pask CM, Henderson IR, Allison SJ, Shepherd SL, Phillips RM, McGowan PC

Conducting metallopolymers have been investigated for a variety of applications due to their ability to take advantage of both the mechanical processability of the polymer material, as well as the optical and electronic properties of the metal. Our project goal is to design, synthesize and characterize novel iridium(III)-containing conducting metallopolymers for use as the active layer in polymer light-emitting diodes. We have utilized thiophene functionalized ligands that can be readily electropolymerized into conducting polymer thin films and can be easily incorporated into a device structure. Iridium(III) was chosen as the metal center due to its promising photophysical properties, as similar complexes have demonstrated high luminescent quantum yields and short phosphorescent lifetimes. The coordination environment around the metal can be altered synthetically to tune the emission wavelength across the visible spectrum. The synthetic control over the polymer backbone, as well as the iridium(III) ligand environment, allowed us to independently vary each component, which has provided a variety of materials. The materials are characterized through 1H and 13C NMR, mass spectrometry, elemental analysis, electrochemistry, X-Ray diffraction and X-Ray Photoelectron Spectroscopy. The photophysical properties of the materials are studied through UVvii Visible absorption spectroscopy, UV-Vis-NIR spectroelectrochemistry and steadystate/ time-resolved emission spectroscopy. / text

With the ever expanding utility of transition metal catalysis, there has been a thrust both to develop catalysts with unique selectivites or activites, and to understand the factors which govern these characteristics at both a fundamental and practical level. Olefin metathesis has become an essential reaction for the synthesis of small molecules in addition to polymeric materials. We have pursued two distinct ligand classes based on diaminocarbenes with novel architectures to address specific limitations within this useful class of reactions: 1) limited access to polymeric materials with controlled microstructures and 2) poor stereoselectivity in Ru-catalyzed cross-metathesis (CM) reactions. Numerous phosphines and N-heterocyclic carbenes (NHCs) have been used as ligands for Ru metathesis catalysts, and the resulting activity is very sensitive to their steric and electronic nature. We envisioned that we could take advantage of this dependence by developing a catalyst with tunable ligand donicity. Redox-switchable ligands can lead to catalysts whose selectivity and/or activity are dependent upon the ligand oxidation state. Towards this purpose, we have developed a ligand which incorporates a 1,1’-disubstituted ferrocene moiety into the backbone of a diaminocarbene (FcDAC). Upon ligation of FcDAC to various transition metals, we were able to use cyclic voltammetry and a spectroelectrochemical FT-IR experiment to show electronic communication between FcDAC and the coordinated metal. We then pursued Ru metathesis catalysts incorporating these ligands. The ring-opening metathesis polymerization of 1,5-cyclooctadiene was studied using [(FcDAC)(PPh₃)Cl₂Ru=(3-phenylindenylid-2-ene)] as the catalyst. Chemical redox reactions were used to establish the ability of FcDAC to impart redox-tunable properties to Ru metathesis catalysts. A new ligand class pioneered in our group, N-aryl,N-alkyl acyclic diaminocarbenes (ADCs), was also studied in various Ru metathesis catalysts. To our delight, these catalysts showed lower E : Z ratios than analogous NHC ligands in two representative CM reactions. We also investigated the conformational diversity of these differentially substituted ADCs given their ability to rotate about their C–N bonds, in particular, to determine how this might influence their donicity. Complexes of the type [(ADC)Ir(COD)Cl] and [(ADC)Ir(CO)₂Cl] were studied, given the wealth of structural and spectral data available for analogous compounds incorporating related ligand classes. Different conformations resulted depending on the N-substituents and the nature of the metal complex. Interestingly, the electron donating ability of ADC ligands was found to depend on their conformation, as evidenced by FT-IR and cyclic voltammetry. This established a new avenue for tuning the donor properties of differentially substituted ADC ligands. The unique properties of these novel ligand classes were demonstrated in Ru metathesis catalysts. However, on a broader level, these ligands are expected to have utility in diverse catalytic applications. / text

Les travaux de cette thèse portent sur la synthèse et les études en photoluminescence de nouveaux complexes de métaux de transitions (Ir(III), Pt(II), Pd(II)). Le principal objectif est d’obtenir de nouveaux matériaux phosphorescents pour des applications telles que les diodes organiques électroluminescentes (OLEDs) ou la bio-imagerie. L’incorporation de chromophores tels que le pyrene et le naphtalimide au complexe fac-Ir(thpy)3 sera tout d’abord présenté. La synthèse par activation C–H de ces nouveaux complexes sera également étudié. De nouveaux complexes organométalliques ultra-rigides seront ensuite développés. La synthèse ainsi que les analyses en photoluminescence de complexes tetradentate de platine et de palladium seront ensuite décrits. Enfin, une analyse de nouveaux complexes d’iridium comportant des ligands benzimidazoles (iso)-quinoline et bis-benzimidazole sensibles aux variations de pH sera faite. / The work of this thesis is focused on the synthesis and the photoluminescence studies of new 3 raw transition metal complexes (Ir(III), Pt(II), Pd(II)) . The main objective is to obtain new phosphorescent materials for applications such as organic light emitting diodes (OLEDs) and bio- imaging. The incorporation of chromophores such as pyrene and naphthalimide into fac-Ir-(thpy)3 complex will first be presented. The synthesis, by C–H activation, of the new complex will also be studied. New ultra-rigid organometallic complexes will then be developed. The synthesis and the photoluminescence analysis of these tetradentate platinum and palladium complexes will be described. Finally, a study of new iridium complexes incorporating benzimidazoles (iso)-quinoline and bis-benzimidazole ligands sensitive to pH variations will be made.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18471号 / 工博第3907号 / 新制||工||1600(附属図書館) / 31349 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 小澤 文幸, 教授 辻 康之, 教授 中村 正治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Nos últimos anos, complexos de irídio tem sido sugeridos para uso em materiais luminescentes, tais como diodos orgânicos emissores de luz (OLED\'s) e células eletroquímicas emissoras de luz (LEEC\'s). Suas potenciais utilidades como dispositivo é devido as suas características físico-químicas e fotofísicas, as quais são caracterizadas por tempos de vida curtos para o tripleto, estabilidade térmica, além da possibilidade de modificar a emissão sobre uma vasta gama de cores do espectro. Atualmente, muitas pesquisas tentam encontrar complexos de irídio com emissão de luz azul. No entanto, embora emissores de luz azul já tenham sido desenvolvidos, existe o problema relacionado a agregação destes complexos. Para resolver este o problema da agregação é necessário modificar a estrutura padrão do complexo com cadeias carbônicas saturadas para evitar empilhamento π-π. Experimentalmente esta é uma tarefa um tanto difícil. Dessa forma, métodos computacionais têm sido viáveis como uma abordagem para entender a estrutura e propriedades eletrônicas dos sistemas estudados. Aqui, é apresentado um estudo teórico baseado na teoria do funcional da densidade (DFT) para investigar a agregação de complexos de irídio, além de predizer como esta pode ser controlada com o uso de grupos substituintes adequados. Os cálculos foram realizados usando funcional PBE0 e conjunto de base 6-31G*, o qual provou ser adequada na descrição das propriedades do complexo. Portanto, cálculos subsequentes mostraram bons resultados, onde os estados excitados foram previstos ser de natureza predominantemente MLCT (transferência de carga do metal para o ligante) para o complexo 1 e LC (carga centrada no ligante) para o complexo 2. Alterações no ambiente químico provou ter grande influência sobre os estados excitados, onde a inclusão do solvente favoreceu a estabilidade, mantendo os estados excitados tripletos com energia entre 3.01 eV e 3.03 eV. Além disso, o uso dos grupos substituintes provou ser de grande importância para prevenir a agregação, especialmente no complexo 2, em que a partir do dímero matriz (sem substituintes) para o complexo substituído 2-1 (com metil) houve uma desestabilização da energia de interação entre os monômeros no dímero por ~ 19.78 kcal/mol, sendo que a energia do primeiro foi estimada ser -39.78 kcal/mol, enquanto o segundo foi -20 kcal/mol. Nossos resultados sugerem que a modificação do complexo torna-se bastante promissora, fazendo uso de pequenos grupos substituintes e cadeias carbônicas alifáticas, evitando assim, a agregação por empilhamento π-π. / In the last few years, iridium complexes have been suggested for use in luminescent materials such as organic light-emitting diodes (OLEDs) and light emitting electrochemical cells (LEECs)1-3. Their potential utility as luminescent devices is due to the physicochemical and photophysical properties, which are featured by short triplet emitting lifetimes (microseconds time scale), thermal stability, besides of possibility to tune the emission over desired spectral range. Actually, many researches try to find iridium complexes with efficient deep-blue emission, in order to use in these devices. Although many deep-blue emitters have been developed, there is still a big problem related to aggregation. So far, little has been reported about iridium complexes in solid environments, such as inorganic matrix of OLEDs and LEECs devices. To solve this issue is needed tune the structure of the complex in order to prevent the aggregation (steric hindrance), by means of drawing saturated carbon chains on the ligands to avoid the π-π stacking. Experimentally, this is a rather challenging and expensive task. In this aspect, computational methods have been performed as approaches to gain deeper insights about the structure and electronic properties of the studied systems. Here, we present a theoretical study based on density functional theory to investigate the aggregation iridium complexes, in addition to predict how this can be controlled with the use of suitable substituent groups. Calculations were performed using functional PBE0 and 6-31G* basis functions, which proved adequate in describing the properties of the complex. Therefore, subsequent calculations showed good results, where the excited state of the complex are provided, these being predominantly MLCT (metal to ligand charge transfer) nature for the complex 1 and LC (ligand centered) nature to complex 2. Changes in the chemical environment proved to have great influence on the excited states, where the inclusion of the solvent favored its stability, keeping the triplet excited states with energy between 3.01 and 3.03 eV. Furthermore, the use of substituent groups proved to be of great importance to prevent aggregation, especially in complex 2, wherein from the matrix dimer (no substituted) to complex with methyl groups there was a destabilization of the interaction energy between the monomers in the dimer by ~ 19.78 kcal / mol, being that the energy of the first was -39.78 kcal / mol, while the second was to -20 kcal / mol. Our results suggest that the modification of the complex becomes quite promising, making use of small groups and aliphatic carbon chains, thus avoiding aggregation by stacking.

The structural, electronic, and optical properties of a series of organic pi-conjugated polymer, oligomer, or molecular materials of interest for applications in organic electronics are described. For this purpose, quantum-chemical techniques ranging from Density Functional Theory to Hartree-Fock ab initio and semiempirical methods are used to evaluate the charge-transport, charge-transfer, and electroluminescence properties of pi-conjugated organic materials. First, the effect of electronic polarization on the charge-transport parameters of organic semiconductors is discussed. A generalized methodology based on a basis set orthogonalization procedure is developed to determine reliable charge-transport characteristics. The charge-transport parameters of a number of organic semiconductors such as oligoacenes and derivatives are studied with this methodology. Then, triplet emitters, in particular iridium complexes, that achieve high efficiency electroluminescence in organic light-emitting diodes are discussed. The effects of ligand substitution and orientation on the luminescent properties of iridium compounds are investigated in order to develop structure-properties relationships. The emission properties of these complexes are found to be governed by an interplay between metal-to-ligand charge transfer excitations and ligand-centered and/or interligand excitations. The extent of mixing of these various excitations turns out to be highly dependent on the nature of the substituents. Design strategies to shift the emission color towards deep blue are proposed. Finally, several classes of materials acting as hosts for phosphorescent emitters are studied. It is shown that restricting the conjugation length leads to high energy gap host materials suitable for blue phosphorescent emitters.

Nos últimos anos, complexos de irídio tem sido sugeridos para uso em materiais luminescentes, tais como diodos orgânicos emissores de luz (OLED\'s) e células eletroquímicas emissoras de luz (LEEC\'s). Suas potenciais utilidades como dispositivo é devido as suas características físico-químicas e fotofísicas, as quais são caracterizadas por tempos de vida curtos para o tripleto, estabilidade térmica, além da possibilidade de modificar a emissão sobre uma vasta gama de cores do espectro. Atualmente, muitas pesquisas tentam encontrar complexos de irídio com emissão de luz azul. No entanto, embora emissores de luz azul já tenham sido desenvolvidos, existe o problema relacionado a agregação destes complexos. Para resolver este o problema da agregação é necessário modificar a estrutura padrão do complexo com cadeias carbônicas saturadas para evitar empilhamento π-π. Experimentalmente esta é uma tarefa um tanto difícil. Dessa forma, métodos computacionais têm sido viáveis como uma abordagem para entender a estrutura e propriedades eletrônicas dos sistemas estudados. Aqui, é apresentado um estudo teórico baseado na teoria do funcional da densidade (DFT) para investigar a agregação de complexos de irídio, além de predizer como esta pode ser controlada com o uso de grupos substituintes adequados. Os cálculos foram realizados usando funcional PBE0 e conjunto de base 6-31G*, o qual provou ser adequada na descrição das propriedades do complexo. Portanto, cálculos subsequentes mostraram bons resultados, onde os estados excitados foram previstos ser de natureza predominantemente MLCT (transferência de carga do metal para o ligante) para o complexo 1 e LC (carga centrada no ligante) para o complexo 2. Alterações no ambiente químico provou ter grande influência sobre os estados excitados, onde a inclusão do solvente favoreceu a estabilidade, mantendo os estados excitados tripletos com energia entre 3.01 eV e 3.03 eV. Além disso, o uso dos grupos substituintes provou ser de grande importância para prevenir a agregação, especialmente no complexo 2, em que a partir do dímero matriz (sem substituintes) para o complexo substituído 2-1 (com metil) houve uma desestabilização da energia de interação entre os monômeros no dímero por ~ 19.78 kcal/mol, sendo que a energia do primeiro foi estimada ser -39.78 kcal/mol, enquanto o segundo foi -20 kcal/mol. Nossos resultados sugerem que a modificação do complexo torna-se bastante promissora, fazendo uso de pequenos grupos substituintes e cadeias carbônicas alifáticas, evitando assim, a agregação por empilhamento π-π. / In the last few years, iridium complexes have been suggested for use in luminescent materials such as organic light-emitting diodes (OLEDs) and light emitting electrochemical cells (LEECs)1-3. Their potential utility as luminescent devices is due to the physicochemical and photophysical properties, which are featured by short triplet emitting lifetimes (microseconds time scale), thermal stability, besides of possibility to tune the emission over desired spectral range. Actually, many researches try to find iridium complexes with efficient deep-blue emission, in order to use in these devices. Although many deep-blue emitters have been developed, there is still a big problem related to aggregation. So far, little has been reported about iridium complexes in solid environments, such as inorganic matrix of OLEDs and LEECs devices. To solve this issue is needed tune the structure of the complex in order to prevent the aggregation (steric hindrance), by means of drawing saturated carbon chains on the ligands to avoid the π-π stacking. Experimentally, this is a rather challenging and expensive task. In this aspect, computational methods have been performed as approaches to gain deeper insights about the structure and electronic properties of the studied systems. Here, we present a theoretical study based on density functional theory to investigate the aggregation iridium complexes, in addition to predict how this can be controlled with the use of suitable substituent groups. Calculations were performed using functional PBE0 and 6-31G* basis functions, which proved adequate in describing the properties of the complex. Therefore, subsequent calculations showed good results, where the excited state of the complex are provided, these being predominantly MLCT (metal to ligand charge transfer) nature for the complex 1 and LC (ligand centered) nature to complex 2. Changes in the chemical environment proved to have great influence on the excited states, where the inclusion of the solvent favored its stability, keeping the triplet excited states with energy between 3.01 and 3.03 eV. Furthermore, the use of substituent groups proved to be of great importance to prevent aggregation, especially in complex 2, wherein from the matrix dimer (no substituted) to complex with methyl groups there was a destabilization of the interaction energy between the monomers in the dimer by ~ 19.78 kcal / mol, being that the energy of the first was -39.78 kcal / mol, while the second was to -20 kcal / mol. Our results suggest that the modification of the complex becomes quite promising, making use of small groups and aliphatic carbon chains, thus avoiding aggregation by stacking.

Triarylborane Functionalized Dicyanovinyl and Acetylacetone Based Molecular Platforms: Building Blocks for Multiple Anion Sensors and Efficient Phosphorescence Emitters The main objective of this thesis is to design a simple strategy for triarylborane based multiple anion sensors and development of triarylborane incorporated phosphorescent metal complexes. The thesis consists of eight chapters and the contents of each chapter are given below. Chapter 1 This chapter gives a general introduction to recent advances relevant to the theme of the thesis. A review of the fundamental characteristics of triarylboranes and their applications in various fields such as chemical sensors and optoelectronics is presented. Advances in boron chemistry in the areas such as anion sensors, solid state emissive and phosphorescence materials are discussed in detail. The scope of the thesis is outlined at the end of the chapter. Chapter 2 The second chapter deals with the general experimental techniques and synthetic procedures followed in this thesis. Chapter 3 This chapter deals with a rational design strategy for differential identification of fluoride and cyanide ions using TAB based sensors. In general, most of the triarylboranes give similar optical responses towards fluoride and cyanide ions as they follow similar sensing mechanism. In order to circumvent this problem, two TAB-DCV conjugates (1 and 2) are designed and synthesised. The DCV unit is highly specific for cyanide ion owing to the presence of electrophilic carbon center. Probes 1 and 2 differ in steric crowding around the boron center. The less crowded boron center in 1 binds with fluoride as well as with cyanide ions giving similar optical response (luminescence is quenched in presence of F¯ and CN¯). In the case of 2, selectivity of boron center towards fluoride is tuned by increasing the steric crowding around the boron unit. The dicyanovinyl unit acts as selective sensing site for cyanide ions. As a result, 2 gives different fluorogenic response towards the anions F¯ and CN¯ which were considered as interfering anions in TAB based sensor chemistry. Thus, a modular design principle is developed for differential identification of fluoride and cyanide ions using TAB. Chapter 4 In this chapter, detailed photophysical studies of TAB-amine-DCV conjugates and colorimetric discrimination of fluoride and cyanide ions are discussed. Presence of amine based donor between the two electron deficient sites enhances the electronic conjugation in 3−5. Since there are two different acceptor sites with a common donor, two distinct charge transfer transition bands are observed in the visible region of electromagnetic spectrum. The absorption and emission spectra of these compounds show pronounced sensitivity to solvent polarity, signifying large excited state dipolmonents. Anion binding studies confirms that these compounds are highly selective towards fluoride and cyanide ions. Fluoride ions selectively interact with boron center and block the corresponding charge transfer transition thereby leading to a distinct colour change which is observable by naked eye. On the other hand, cyanide interacts with boron as well as DCV unit and blocks both the charge transfer transitions which results in disappearance of colour. Hence, compounds 4 and 5 exhibit different colorimetric signals for fluoride and cyanide ions. Since the absorption bands of 3 do not fall in the visible region, it does not show any colorimetric response towards the aforementioned anions. The anion sensing mechanisms are established by 1H, and 19F NMR studies. Chapter 5 This chapter presents a systematic study of the effect of length of π-electronic conjugation on the optical properties and anion sensing abilities of a series of TAB-oligothiophene-DCV conjugates (6−8). Their absorption as well as emission bands undergo redshift upon increasing the number of thiophene units between TAB and DCV units as the π-electronic conjugation in 6−8 is greatly dependent on the number of thiophene units. Their fluorescence emission is highly sensitive to solvent polarity. In the case of 6, the emission band undergoes a redshift with reduced intensity. In the case of 7 the emission band undergoes a redshift but the intensity is not affected by solvent polarity. In the case of 8, the emission band undergoes redshift with enhanced intensity in polar solvents. Interestingly, 7 and 8 show solvent viscosity dependent fluorescence. Structural reorganisation is restricted in viscous medium and results in enhanced emission for 7 and 8. Further, these compounds exhibit selective response towards the fluoride and cyanide ions with different colorimetric responses. Test strips made up of probes 7 and 8 have potential application in identifying fluoride and cyanide ions in aqueous medium. Chapter 6 This chapter describes synthesis and optical characterisation of triarylborane incorporated acetylacetone (acacH) ligands (9, 10) and their borondifluoride complexes (11, 12). AcacH ligands and BF2 complexes show solvent dependent emission phenomena due to the involvement of charge transfer transition. Their optical properties are highly dependent on molecular conformations. Complex with duryl spacer (12) exhibits more red shifted emission in polar solvents due to the enhanced charge transfer transition facilitated by twisted rigid geometry. In presence of fluoride and cyanide ions, the borondifluoride complexes are not stable. The anions concomitantly interact with tricoordinate boron as well as acac-BF2 unit to give rise to complex pattern of photoluminescence spectral changes during the titration experiment. The binding pathway and the possible species involved are established with the help of 1H, 19F and 11B NMR spectral studies in presence of the anions. Complexes 11 and 12 act as selective chemodosimetric sensors for fluoride and cyanide ions. Chapter 7 In this chapter, the synthesis and optical characterisations of triarylborane conjugated cyclometalated platinum complexes are discussed. A series of square planar platinum complexes are synthesised with different cyclometalating ligands. Complexes (13−18) exhibit a range of luminescence from green to red in solution as well as in the solid state. Their emission intensities are highly sensitive towards atmospheric oxygen suggesting that they originate from a triplet excited state. A maximum of 85% quantum yield is observed for complex 15 in solution state while complex 14 showed a maximum of 58% quantum yield in solid state. Complexes with rigid molecular conformation (14, 16 and 18) showed higher luminescence quantum yield than those having phenyl spacer (13, 15 and 17). The sterically encumbered boryl (-BMes2) group significantly reduces π-π stacking between the square planar entities. Thus, complexes 13−18 show bright luminescence in solid state compared to model complexes without boryl group. The effect of Lewis acidic boron center on luminescence behaviour is explored by fluoride binding studies. Chapter 8 This chapter is divided into two parts. Part-I describes the synthesis and optical characterisation of triarylborane conjugated cyclometalated iridium complexes (19−24). They are brightly luminescent in solution state with high sensitivity towards atmospheric oxygen. Complex 20 shows a highest quantum yield of 91%. Interestingly, under ambient atmospheric conditions, they exhibit a rare type of dual emission. Life time data suggest that the lower energy emission band originates from cyclometalated iridium based triplet excited state while higher energy emission band originates from boryl ased singlet excited state. Fluoride binding at the boron site results in luminescence quenching; evidently, tri-coordinate boron has a major contribution to the luminescence features of these iridium complexes. Part-II deals with synthesis of triarylborane conjugated pyrazole ligand (25) and its binuclear iridium complexes (26−28) in which two iridium centers are bridged by hydroxo as well as pyrazolato ligands. These binuclear iridium complexes exhibit higher luminescence quantum yield than TAB-acac-Iridium complexes (mononuclear complexes; part I). Binding of fluoride ions at the boron center has a minor impact on their luminescence nature. High sensitivity of their luminescence towards atmospheric oxygen indicates the involvement of triplet excited state in their emission process.