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Made available in DSpace on 2014-06-11T19:29:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2001Bitstream added on 2014-06-13T20:59:20Z : No. of bitstreams: 1 poelhsitz_g_me_araiq.pdf: 1569742 bytes, checksum: 1c42137408ccfde6142b90c3644361e4 (MD5) / Neste trabalho novos complexos nitrosilos de rutênio (II) contendo bifosfinas foram obtidos e caracterizados. A série de complexos [RuCl3(NO)(P-P)] (1) foi utilizada como precursora na obtenção de compostos do tipo [Ru(pyS)2(P-P)] (2), P-P = dppe, c-dppen, dppp e dppb e [Ru(pyS)2(NO)(η1-P-PO)]PF6 (3), P-P = dppm e dppb; pyS = 2-mercaptopiridina, em rendimentos e pureza satisfatórios. Utilizou-se as técnicas usuais para caracterização dos complexos, entre elas: espectroscopias IV, UV/vis e RMN multinuclear (1H, 13C{1H} e 31P{1H}), voltametria cíclica, voltametria de pulso diferencial e análise elementar. A maioria dos compostos forneceu monocristais adequados para estudos por difração de raios-X. Os complexos do tipo (1) foram obtidos por rotas sintéticas já estabelecidas em nossos laboratórios. O inédito fac-[RuCl3(NO)(c-dppen)] foi isolado e caracterizado, tendo inclusive a estrutura cristalográfica resolvida. Este fato permitiu a realização de interessantes comparações deste com o isômero mer-[RuCl3(NO)(dppb)]. Adicionalmente, obtevese a estrutura cristalográfica do [RuCl3(NO)(c-dppen)] e realizou-se pela primeira vez ensaios eletroquímicos para toda a série (1) e experimentos de RMN multinuclear para o mer-[RuCl3(NO)(dppb)]. Assim, aproveita-se a oportunidade para algumas discussões adicionais, importantes para o melhor entendimento da série como um todo e para fins de comparação com os complexos derivados. Os produtos isolados nas reações com a pySH mostraram ser dependentes da bifosfina utilizada, já que o mesmo procedimento foi utilizado para obtenção dos derivados (2) e (3). A série (2) acima citada, com exceção do derivado com a c-dppen que é inédito, foi obtida anteriormente na literatura por rota de síntese diferente da aqui descrita. Apresentase a caracterização e discussão dos resultados... / In this work new nitrosyl complexes of ruthenium (II) containing diphosphines were obtained and characterized. The series of compounds [RuCl3(NO)(P-P)] (1) was used as the precursor to obtain compounds of the type [Ru(pyS)2(P-P)] (2), P-P = dppe, c-dppen, dppp and dppb and [Ru(pyS)2(NO)(η1-PPO)] PF6 (3), P-P = dppm and dppb; pyS = 2-mercaptopyridine, in acceptable yields and purity. Standard techniques were used for characterization of the compounds, among them: infrared, visible-UV and multinuclear NMR (1H, 13C{1H} and 31P{1H}) spectroscopies, cyclic voltammetry, pulse diferential voltammetry and elemental analysis. Most of the studied complexes supplied crystals suitable for X-ray crystal structure analysis. Compounds of type (1) were obtained by synthetic routes previously established in our laboratories. The unpublished fac-[RuCl3(NO)(dppb)] was isolated, characterized and had its crystallographic structure solved. This fact allowed interesting comparisons with the geometrical isomer mer-[RuCl3(NO)(dppb)]. In addition, the crystallographic structure of the [RuCl3(NO)(c-dppen)] was obtained and electrochemical characterization for all series (1) as well as multinuclear NMR experiments for the mer-[RuCl3(NO)(dppb)] were carried out for the first time. These studies offer us the opportunity for some additional discussions about the precursor complexes important to the comparisons with the results for the derivative compounds. The isolated products of the reactions with 2-mercaptopyridine ligand showed to be dependent on the diphosphine from the precursor, since the same procedure was used for obtaining derivatives (2) and (3). The series (2), mentioned above, was described previously in the literature, except for the c-dppen derivative, utilizing another synthetic route. The characterization and discussion ...(Complete abstract, click electronic access below)

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This study entails the synthesis, spectroscopic and structural characterization of new rhenium complexes with multidentate imine-, amine-, thione-, thiol-, hydroxy- and carboxamide chelates in various oxidation states. Rhenium(I) and (V) complexes with imidazolidine, pyrimidine and bridging pyridyl derivatives are reported in Chapter 3. The reactions of the potential tridentate N,N,Odonor ligand 2,2'-dipyridylketone (dpk) with trans-[ReOCl3(PPh3)2], (n-Bu4N)[ReOCl4] and trans-[ReOI2(OEt)(PPh3)2] led to the isolation of cis-[ReOCl2(edpm)], cis-[ReOCl2(dpk.OH)] and [ReO3(dpk.OH)] respectively (see Scheme 1). The reaction of (E)-N-((pyridine-2-yl)methylene)benzo[d]thiazol-2-amine (pbt) with trans- [ReOCl3(PPh3)2] produced a mononuclear oxorhenium(V) complex cis- [ReOCl2(epm)(PPh3)]. Both dpk and pbt exhibited a nucleophilic attack by acetonitrile (for Hedpm), water (for dpk) and ethanol (for pbt) leading to chelates that act as uninegative tridentate N,N,O- and bidentate N,O-donor chelates respectively. The reaction of [Re(CO)5Cl] with 2,3-dihydro-2,2-di(pyridin-2-yl)-1H-benzo[d]imidazole (H2dpb), (2,6-diaza-cyclohex-1-enylolonium)2-aza-benzoate (H2den) and 2-(2-(pyridine-2-yl)imidazolidin-2-yl)pyridine (H2pip) (see Scheme 1) gave rise to novel rhenium(I) complexes fac-[Re(CO)3(H2dmb)Cl], fac-[Re(CO)3(Hhdm)] and fac-[Re(CO)3(H2pip)]Cl respectively. The monomeric cationic salt fac-[Re(CO)3(H2salbam)]Br and ligand-bridged dimer fac- (μ-H2salet)[Re(CO)3]2 complexes were formed by the reactions of [Re(CO)5X] (X = Br or Cl) with the potentially heptadentate Schiff base 2,2􀆍,2􀆎-tris (salicylideneimino)- triethylamine (H3salet; Scheme 2) respectively. The reactions of the potentially hexadentate ligands acting as tridentate monoanionic N,N,O- or N,O,O-donor chelates N1-(3-(2-hydroxy enzylideneamino) propylamino) ethyl)benzylidenepropane-1,3-diamine (H2salpd) and N,N -bis(salicylidene) -3,6-dioxa-1,8-diaminooctane (H2saldane) (Scheme 2) with [Re(CO)5Cl] led to the isolation of the mononuclear and dinuclear complexes fac-[Re(CO)3(Hsaldane)] and fac-(μ-salpd)[Re(CO)3]2 respectively. The reactions of [Re(CO)5Cl] with the tetradentate ligands 2-{[2-hydroxy-3-{[(E)-(2- hydroxyphenyl)-methylidene]amino}propyl)imino]methyl}phenol (H2hmp), 6-((6E)- ((3E)-3-((oxocyclohexa-2,4-dienyl)methyleneamino)-2-hydroxypropylimino)methyl)- cyclohexa-2,4-dienone (H2hcd.H2O) zwitterion and 2-((1E)-1-((E)-3-(2-hydoxyphenylmethylideneamino)propylimino)methyl)phenol (H2hdp) (see Scheme 2) resulted in the formation of the neutral fac-[Re(CO)3(Hamp)], fac-[Re(CO)3(Hhetp)] and fac- [Re(CO)3(Happ)] respectively. The treatment of 2-((3-(2-hydroxybenzylamino)-propylamino)methyl)phenol (H2hbp) with [Re(CO)3Cl] and trans-[ReOCl3(PPh3)2] gave the fac-[Re(CO)3(Hhbp)] and (μ-O)[ReO(hbp)]2 complexes. The reactions of the ligands H2hmp, H2hdp and H2hap (see Scheme 2) with trans-[ReOBr3(PPh3)2] and trans-[ReOI2(OEt)(PPh3)2] produced dinuclear oxo-bridged rhenium(V) complexes (μ-O)[ReO(hmp)]2, [(μ-O)[ReO(hdp)]2 and (μ-O)[ReO(hap)]2 respectively. The neutral and anionic binding modes of thiosemicarbazones to the fac-[Re(CO)3]+, cis- [ReO2]+ and trans-[ReO2]+ cores have been investigated in Chapter 6. The reactions of the potentially tridentate ligand 1-{1-(2- hydroxyphenyl)ethylidene}-4- phenylthiosemicarbazide (H2hpt) (see Scheme 3) with [Re(CO)5Cl], cis-[ReO2I(PPh3)2]cand trans-[ReO2(py)4]Cl led to the isolation of the complexes fac-[Re(CO)3(H2hpt)2]Cl, [Re(hipt)(Hipht)(PPh3)] and trans-[ReO(hpt)(Hhpt)] respectively. The X-ray crystal analysis of the complexes show that the ligand H2hpt exhibits decomposition, thiol-enol tautomerism and a thiolate-iminium zwitterionic process, and coordinates in the neutral form via its thione sulfur and nitrogen and anionic through the azo nitrogen, thiolate sulfur and acetophenolic oxygen. A series of nitrogen-heterocyclic amide-, acid-, thiol- and diol-based ligands as well as their related monomeric rhenium(III) and (V) complexes have also been studied (see Chapter 7). The reaction of N-(2-(pyrazine-2-carboxamido)phenyl)pyrazine-2- carboxamide (H2ppc) (Scheme 3) with trans-[ReOBr3(PPh3)2] yielded the complex trans- [ReBr2(Hppca)(PPh3)2]. The reactions of trans-[ReOX3(PPh3)2] (X = Cl, Br) with pyridine-2,6-dicarboxylic acid (H2pda) produced the neutral oxorhenium(V) complexes [ReOX2(epca)(PPh3)]. The treatment of trans-[ReOBr3(PPh3)2] with 2-mercaptopyridine- 3-carboxylic acid (H2mpc) gave rise to the rhenium(III) complex [Re(empc)3(PPh3)]. The reaction of 2,6-bis(hydroxymethyl)pyridine (H2bhp) with trans-[ReOI2(EOt)(PPh3)2], trans-[ReOBr3(PPh3)2] and [Re(CO)5Cl] gave the complexes [ReO(Hbhp)2(PPh3)]I.PPh3, cis-[ReOBr2(Hbhp)(PPh3)] and fac-(μ- O)2[Re(CO)3(Hbhp)]2 respectively. Their X-ray crystal structures indicate that the ligand acts as a bidentate monoanionic N,O-donor chelate leaving a free aliphatic hydroxyl group.

Les ribosomes sont les molécules présentes dans toutes les cellules du règne vivant. Ils résultent de l'assemblage d'ARN ribosomiques (ARNr) et de protéines ribosomiques, constituant des particules ribonucléoprotéiques (RNP). Ils jouent un rôle majeur en décodant l'information génétique contenue dans les ARN messagers (ARNm) afin de les traduire en protéines lors du processus de traduction. La production des ribosomes chez les eucaryotes est initiée par la transcription par l'ARN pol I d'un pré-ARNr ribosomique (pré-ARNr) précurseur des ARNr matures 18S, 5.8S et 25S/28S, qui sera modifié chimiquement et digéré par des endo- et exoribonucléases pour aboutir aux ARNr matures. Le pré-ARNr en cours de synthèse s'associe avec des protéines ribosomiques, des petites particules ribonucléoprotéiques (snoRNP) et des protéines dites " non ribosomiques " conduisant à l'assemblage de la particule 90S initiale. Cette particule est ensuite scindée en particules pré-ribosomiques pré-40S et pré-60S, qui vont suivre des voies de maturation indépendantes pour aboutir aux sous unités ribosomiques 40S et 60S mature. La production des ribosomes eucaryotes requiert l'intervention de plus de 200 protéines dites " non ribosomiques ", qui s'associent avec les particules pré-ribosomiques et sont absentes des ribosomes cytoplasmiques matures. Des données obtenues en collaboration suggèrent que cinq protéines non-ribosomiques impliquées dans les étapes précoces de la formation de la grande sous-unité ribosomique, Npa1p, Npa2p, Nop8p, Dbp6p et Rsa3p forment un complexe en l'absence d'ARN ribosomique. Il s'agirait du plus gros complexe connu composé uniquement de protéines, requis pour la formation des sous unités ribosomiques. Nop8p contient un domaine de liaison à l'ARN et pourrait permettre de fixer le complexe au pré-ARNr, et Dbp6p est une potentielle ARN hélicase. Les composants du complexe pourraient constituer des régulateurs et/ou des cibles de Dbp6p. Les objectifs de ma thèse étaient de déterminer si les protéines Npa1p, Npa2p, Nop8p, Dbp6p et Rsa3p forment effectivement un complexe en dehors des pré-ribosomes, de caractériser les interactions protéine/protéine au sein du complexe et sa structure et d'étudier les fonctions de ses composants. Au cours de ma thèse, j'ai mis en évidence que Nop8p, Dbp6p et Rsa3p sont associées aux pré-ARNr 35S, 32S et 27SA2 et font donc partie des mêmes particules pré-ribosomiques que Npa1p et Npa2p. Les protéines Npa1p, Npa2p, Nop8p et Rsa3p forment un complexe stable, qui persiste une fois dissocié des particules pré-ribosomiques. L'observation au microscope électronique à transmission des complexes purifiés révèle la présence de deux types de complexes de tailles différentes. Par ailleurs, l'hélicase Dbp6p interagit avec ce complexe, mais de manière plus labile car elle en est dissociée en présence d'une forte concentration en magnésium. Les analyses de déplétion de chaque membre du complexe montrent que l'absence de Nop8p n'empêche pas les interactions entre Npa1p, Npa2p et Rsa3p, et que l'absence de Npa2p n'empêche pas les interactions entre Npa1p, Nop8p et Rsa3p. En revanche, l'absence de Npa1p déstabilise totalement le complexe. La perte d'expression de Dbp6p affecte également l'efficacité de co-précipitation de ces pré-ARNr, mais dans une moindre mesure. En parallèle, nous avons débuté une étude des interactions protéine/protéine qui s'établissent entre les membres du complexe. Des données préliminaires suggèrent des interactions directes entre Npa1p, Npa2p et Dbp6p et entre Npa1p et Rsa3p. Nous avons également commencé à effectuer des tests d'activité in vitro de l'hélicase Dbp6p qui suggèrent qu'elle présente une activité ATPase. Enfin, nous avons également localisé le site de fixation sur le pré-ARNr de Npa1p situé à proximité de la protéine ribosomique Rpl3, suggérant qu'ils pourraient collaborer dans la compaction du pré-ARNr. / Ribosomes are huge molecular complexes present in all cells of living things. They result from the assembly of ribosomal RNA (rRNA) and ribosomal proteins, constituting ribonucleoproteins (RNP). They play a major role in decoding the genetic information contained in messenger RNA (mRNA) to translate them into proteins during translation. Production of eukaryotic ribosomes is initiated by transcription of a pre-ribosomal rRNA (pre-rRNA) precursor of mature 18S rRNA, 5.8S and 25S / 28S by RNA polymerase I, which is chemically modified and trimmed with endo- and exoribonucleases, in order to form mature rRNAs. The nascent pre-rRNA associates with ribosomal proteins, small ribonucleoprotein particles (snoRNP) and proteins called "non-ribosomal", leading to the assembly of an initial pre-90S particle. This particle is then split into pre-ribosomal pre-40S and pre-60S particles that follow independent maturation pathways leading to mature ribosomal 40S and 60S subunits. Synthesis of eukaryotic ribosomes requires the intervention of more than 200 non-ribosomal proteins that associate with pre-ribosomal particles and are absent from mature cytoplasmic ribosomes. Data obtained in collaboration suggest that five non-ribosomal proteins involved in the early maturation steps of the large ribosomal subunit Npa1p, Npa2p, Nop8p, Dbp6p and Rsa3p form a complex in the absence of ribosomal RNA. It would be the biggest and only known protein module required for the formation of ribosomal subunits. Nop8p contains a RNA binding domain and could tether the complex with pre-rRNA, and Dbp6p is a putative RNA helicase. Components of the complex may constitute regulators and / or Dbp6p targets. The objectives of my thesis were to determine whether Npa1p, Npa2p, Nop8p, Dbp6p and Rsa3p can form a complex outside the context of pre-ribosomes, characterize protein / protein interactions within the complex, and also to study its structure and function. During my thesis, I demonstrated that Nop8p, Dbp6p and Rsa3p are associated with 35S, 32S and 27SA2 pre-rRNAs, and are therefore constitutive of the same pre-ribosomal particles than Npa1p and Npa2p. Npa1p, Npa2p, Nop8p and Rsa3p can form a stable complex that exists once dissociated pre-ribosomal particles. Electron microscopic observation reveal two types of complexes. Furthermore, Dbp6p helicase can interact with this complex, but in a more labile fashion, since it is dissociated in presence of a high concentration of magnesium. Depletion experiments show that the absence of Nop8p does not prevent interactions with Npa1p, Npa2p and Rsa3p, and that the absence of Npa2p does not prevent interactions with Npa1p, Nop8p and Rsa3p. However, the absence of Npa1p strongly destabilizes the complex. Loss of expression of Dbp6p also affects the efficiency of co-precipitation of 35S, 32S and 27SA2 pre-rRNAs, but to a lesser extent. In parallel, we began a study of protein / protein interactions between members of the complex. Preliminary data suggest a direct interaction between Npa1p or Npa2p and Dbp6p, and Npa1p and Rsa3p. We also began conducting an in vitro study of Dbp6p that suggest it has a helicase activity. Finally, by CRAC analysis we show that Npa1p binds adjacent to large ribosomal protein Rpl3 on 25S rRNA, and could collaborate with it in local rRNA folding.

Thermodynamic parameters of solution (DeltaG°s, DeltaH°s, and DeltaS°s) of some haptens [ortho-, meta-, para-, 5-chloro-2-, 6-chloro-2-, 2-chloro-4- and 4-chloro-3- (parahydroxyphenylazo) sodium benzoate] and three cyclodextrins (Delta, Delta and Delta) were carried out in different reaction media. Thermodynamic parameters for the transfer (DeltaG°t, DeltaH°t, DeltaS°t) of haptens and their anions from water to methanol and from water to N,N'-Dimethylformamide were derived. In addition, transfer free energy, enthalpy and entropy of cyclodextrins from water to N,N'-Dimethylformamide are reported. Thermodynamic parameters of complexation between haptenic anions and cyclodextrins were investigated in water and in N,N'-Dimethylformamide and their transfer quantities from water to N,N'-Dimethylformamide are also given. It was found that the selected haptens (anions) are better solvated in methanol than in water than in N,N'-Dimethylformamide. The transfer enthalpies of the anions (data based on the Ph4AsPh4B convention) from water to methanol and from water to N,N'-Dimethylformamide [DeltaH°t (X-)] are largely compensated by their transfer entropies [DeltaS°t (X-)]. As far as solution thermodynamic data of cyclodextrins in water and N,N'-Dimethylformamide are concerned, it was noticed that a compensation effect between the DeltaHs and DeltaS°s values is taking place in water and in N,N'-Dimethylformamide. Only three anions complex with alpha, and gamma-cyclodextrins in water, whereas four haptens form complexes with alpha, beta and gamma-cyclodextrin in N,N'-Dimethylformamide. Again a compensation effect for cyclodextrin-anion complexes was observed in water and in N,N'-Dimethylformamide. A cavity size effect was shown during the formation of cyclodextrin-hapten complexes. Anion-cyclodextrin interaction becomes weaker with an increase in the cavity of cyclodextrin. Inclusion complexes (axial) are found to take place in water and lid-type (equatorial) complexes are found between these haptenic anions and cyclodextrins in N,N'-Dimethylformamide. The transfer parameters for the cyclodextrin-anion complexes were calculated using a thermodynamic cycle. This is the first set of data ever reported on the transfer of cyclodextrin adducts among solvents.

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M.Sc. (Chemistry) / Please refer to full text to view abstract

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