A series of cis- and trans-bis(ethynyl)platinum complexes containing dimethyldihydropyrene (DHP) photochromic compounds were synthesized from RDHPCCH (R = H, CH3CO, PhCO, 1-naphthoyl and benzo[e]) and platinum chloride with appropriate ancillary ligands (PEt3, PPh3, dppe, bipy and phen). The complexes were studied using mass spectrometry, NMR spectroscopy (1H, 13C, 31P and 195Pt) and IR. The X-ray structural information for bis(DHP-ethynyl) platinum complexes 44, 45, 47, 49, and 52 revealed that the Pt complexes possessed a square planar geometry at the metal centers. These platinum complexes are T type photochromic compounds. The BDHP-derived platinum complexes 48, 49, and 52 open completely when irradiated by visible light (λ > 590 nm). The photoopening rates for the platinum complexes are about 4 times slower than the corresponding DHP-alkynes. All the alkynyl platinum complexes close thermally faster than the corresponding free alkynes, and the closing rate is not affected substantially by changing the ancillary phosphine ligands. The BDHP-ethynyl platinum complexes with PEt3, PPh3 and dppe ligands have similar thermal closing half lives at 25°C of τ1/2 = 42 h, 38 h and 33 h, respectively, in contrast to the half life τ1/2 = 62 h of the BDHP-ethyne 40. The first cyclobutadienyl cobalt substituted dihydropyrenes were prepared by CpCo(CO)2 cyclization of a series of dihydropyrenyl ethynes. When the other alkyne substituent was small (methyl or carboxyethyl) only cis (head-to-head) isomers were obtained, but with larger sized groups, mixed head-to-head and head-to-tail isomers were obtained. The crystal structure of complex 21 indicated some unusually short bond distances were present. By comparison of the NMR and bond length data for complexes 21 or 69 with those for phenyl-DHP 60, the aromaticity of the cyclobutadienyl cobalt fragment was estimated quantitatively to be at least as large as that of benzene. The organometallic fragment [Cbd-Co-Cp] substantially slowed the DHP photoopening reaction of complex 72 relative to precursors 67 or 35. DHP[e]tropone, 17, DHP[e]tropylium cation, 18 and DHP[e]cyclooctatetraene dianion, 20 were synthesized to study the relative bond localizing abilities of COT dianion 80 (105 % relative to benzene), tropylium cation 15 (55 % relative to benzene), tropone 79 (13 % relative to benzene) using DHP as the NMR probe. The internal methyl protons of DHP resonated at δ -3.56 for 17, δ -2.61 for 18 and δ -1.38 for 20. Cycloheptatrienyl anions 111, 112 and 19 were made from cyclohepta-2,4,6-triene (CHT) isomers 107 and 108 (for two anions, 112 and 19). The internal methyl protons of their DHP resonated at δ -2.52, 2.67 for 111, δ -0.80, -0.84 for 112 and δ +2.10 for 19. The anion 19 was best taken as a 20π electron paratropic system. The homo-aromaticity of the CHT isomers 107, 108 and 117 was estimated based on the NMR data and X-ray structural data. Obvious anisotropic effects existed and the bond localization ability of the CHT (24% based on NMR data for 108) may have a large error. The ring inversion barriers of the COT 82 and CHT 77 were measured using variable temperature NMR spectroscopy as 13.9 and 8.7 kcal/mol, respectively. Five X-ray crystallography structures were obtained for 99B, 17, 108, 117 and 125 and the information was used in estimating the bond localization abilities and in establishing absolute stereochemistry / Graduate

Foram determinadas as estruturas de três complexos de Platina, dois complexos de estanho e um ligante orgânico. AS intensidades das reflexões foram medidas com umdifratômetro CAD-4. As estruturas foram resolvidas por métodos diretos ou pela função de Patterson e refinadas por mínimos quadrados. Bis (fenilsulfonil) etano, C14H14(SO2)2, foi obtido durante as tentativas de sintetizar ligantes para serem usados na complexação com diversos organo-estânicos, o cristal pertence ao sistema moniclínico, P21/n, a= 8,495(3), b= 10,159(1), c= 9,072(1)&#197, &#946= 116,23(2) &#176, V= 702,3(3) &#1973, Z= 2, dcalc= 1,467g.cm-3. Cis-dicloro[meso-1,2-bis(n-propilsulfinil)etano]platina(II), PtCl2. (PrSO)2C2H4, o cristal pertence ao sistema ortorrômbico, P212121, a= 7,360(2), b= 9,793(2), c= 19,369(2)&#197, V= 1396,1(4)&#1973, Z= 4, dcalc= 2,25g.cm-3. Trans-diclorol[(trietilfosfina) (2-metilsulfinil)piridina)]platina(II), Et3PPtCl 2.PySOMe, o cristal pertence ao sistema monoclínico, P21/c, a= 8,067(3), b= 8,5184(9), c= 25,592(3)&#197, &#946= 92,000(9)&#176, V= 1757,6(7)&#1973, Z= 4, dcalç= 1,98g.cm-3. Trans-dicloro [(trietilfosfina)(2-n-propilsulfinil)piridina)]platina(II), Et3PPtCl2.PySOPr, o cristal pertence ao sistema triclínico, P-1, a= 8,254(3), b= 8,377(4), c= 14,531(4)&#197, &#945= 87,14(3), &#946= 82,83(3), &#933= 84,10(3)&#176, V= 991,0(7)&#1973, Z= 2, dcalc= 1,78g.cm-3. Mer-tricloro [(2-metilsulfinil)benzotiazol)]metilestanho(IV), MeSnCl3.BtSOMe)2, o cristal pertence ao sistema monoclínico, C2/c, a= 20,083(2), b= 17,406(1), c= 14,415(2)&#197, &#946= 108,06(3), V= 4790,5(8)&#1973, Z= 8, dcalc= 1,78g.cm-3. Hidroxi cloreto de difenil estanho (IV) + mesobis (fenilsulfinil)metano, SnClOHPh2 + Ph2(SO) 2CH2, o cristal pertence ao sistema monoclínico, P21/c, a= 10,540(3), b= 9,743(1), c= 24,099(7)&#197, &#946= 92,95(2), V= 2471(1)&#1973, Z= 4, dcalç= 1,58g.cm-3 / The structures of three platinum complexes, two organotin compounds and organic ligand were determined. The reflection intensities were measured with a CAD-4 automatic diffractometer. The structures were solved by direct methods or the Patterson function and were refined by least squares method. Bis (phenylsulfonyl)ethane, C14H14(SO2)2, was obtained among attempts to synthesize ligands to be used for complexation with several organotins, the crystal belongs to the monoclinic system, P21/n, a= 8,495(3), b= 10,159(1), c= 9,072(1)&#197, &#946= 116,23(2) &#176, V= 702,3(3) &#1973, Z= 2, dcalc= 1,467g.cm-3. Cis-dichloro [ meso 1,2-bis(n-propylsulphinyl)ethane]platinum(II), PtCl2. (PrSO)2C2H4 the crystal belongs to the orthorhombic system, P212121, a= 7,360(2), b= 9,793(2), c= 19,369(2)&#197, V= 1396,1(4)&#1973, Z= 4, dcalc= 2,25g.cm-3. Trans-dichloro [(triethylphosphine) (2-methylsulphinyl)pyridine)]platinum(II), Et3PPtCl 2.PySOMe, the crystal belongs to the monoclinic system, P21/c, a= 8,067(3), b= 8,5184(9), c= 25,592(3)&#197, &#946= 92,000(9)&#176, V= 1757,6(7)&#1973, Z= 4, dcalç= 1,98g.cm-3. Trans-dichloro [(triethylphosphine) (2-npropylsulphinyl) pyridine)]platinum(II), Et3PPtCl2.PySOPr, the crystal belongs to the orthorhombic system, P-1, a= 8,254(3), b= 8,377(4), c= 14,531(4)&#197, &#945= 87,14(3), &#946= 82,83(3), &#933= 84,10(3)&#176, V= 991,0(7)&#1973, Z= 2, dcalc= 1,78g.cm-3. Mer-trichloro[(2-methylsulphinyl)benzothiazole)]methyltin(IV), MeSnCl3.BtSOMe)2 the crystal belongs to the monoclinic system, C2/c, a= 20,083(2), b= 17,406(1), c= 14,415(2)&#197, &#946= 108,06(3), V= 4790,5(8)&#1973, Z= 8, dcalc= 1,78g.cm-3. Hidroxe chloride diphenyl tin (IV) + mesobis (phenylsulphinyl)methane, SnClOHPh2 + Ph2(SO) 2CH2 the crystal belongs to the monoclinic system, P21/c, a= 10,540(3), b= 9,743(1), c= 24,099(7)&#197, &#946= 92,95(2), V= 2471(1)&#1973, Z= 4, dcalç= 1,58g.cm-3

Desde a descoberta da cisplatina várias tentativas têm sido feitas com o objetivo de desenvolver novos quimioterápicos com menor toxicidade e efeitos colaterais melhorados para tratar o câncer. Complexos de coordenação com metais de transição variados vêm sendo estudados buscando melhoras na biodisponibilidade, seletividade e efeitos adversos. Neste sentido, o presente trabalho consiste na síntese e caracterização estrutural de complexos de PdII e PtII com ligantes derivados de tiossemicarbazidas contendo o grupo fluoróforo pireno visando a obtenção de potenciais agentes antitumorais. Os agentes quelantes foram preparados a partir de reações de condensação entre o pirenocarboxaldeído e a tiossemicarbazida desejada resultando em compostos 1-pirenocarboxaldeído-N(3)-R-tiossemicarbazona, H2PrR, onde R = etil ou ciclohexil, Pr = pireno. A partir dos ligantes H2PrR foram realizadas as reações de complexação com os íons metálicos PdII e PtII, sendo possível obter duas classes de complexos com diferentes características: complexos monoméricos contendo ligantes clorido e trifenilfosfano do tipo [MCl(PPh3)(HPrR)] e complexos tetraméricos do tipo [M4(μ-S-PrR-κ3-C,N,S)4], onde M = PdII ou PtII, R = etil ou ciclohexil. Nas duas primeiras séries, o grupo R foi modificado por etil e ciclohexil para investigar a correlação entre lipoficilidade e atividade antiproliferativa, enquanto que o grupamento pireno foi incluído pensando que um maior número de unidades aromáticas possivelmente melhoraria a intercalação com o DNA e/ou ser utilizado como um marcador celular. A caracterização dos complexos envolveu técnicas como: análise elementar, espectroscopia na região do infravermelho e do UV-Vis, condutimetria, ressonância magnética nuclear (1H e 13C RMN) e difração de raios X em monocristal. As análises mostraram que os agentes complexantes podem atuar em diferentes modos coordenação tanto com relação à denticidade quanto à carga. A atividade antiproliferativa dos novos compostos de PdII e PtII foi determinada, sendo que vários deles apresentaram IC50 promissores contra células de câncer de ovário e, em muitos casos, as atividades observadas foram melhores do que a da cisplatina. Os dados obtidos indicam efeitos diferentes nos resultados de atividade biológica para os centros metálicos (Pd vs Pt) e ligantes utilizados (Etil vs Ciclohexil). Estudos de captação e distribuição celular mostraram que o complexo [PdCl(PPh3)(HPrCh)] atinge o núcleo celular. Com o intuito de verificar possíveis alvos biológicos, testes de interação com o DNA, ciclo celular e inibição da enzima Top IB foram realizados para os compostos. Os resultados do ciclo celular, mostraram uma maior inibição nos estádios S e G2/M para os complexos do tipo [PdCl(PPh3)(HPrR)]. Diante dos resultados obtidos, verificou-se que a Top IB é um dos alvos moleculares para os complexos do tipo [MCl(PPh3)(HPrR)], um mecanismo diferente da cisplatina. Estes resultados preliminares são bastante promissores e mostram que alguns dos complexos estudados neste trabalho apresentam-se como potenciais agentes para serem usados na terapia do câncer em combinação com os demais fármacos em uso clínico. / Since the discovery of cisplatin, many attepemts have been made to prepare new drugs with less cytotoxicity and side effects. Coordination complexes based on a variety of transition metals have been developed in the search for improved bioavailability, selectivity and reduced adverse side-effects. This work consists on the synthesis and structural characterization of PdII and PtII complexes with chelating compounds derived from thiosemicarbazides containing the pyrene fluorophore group aiming to obtain potential antitumor compounds. The chelating agents were prepared from condensation reactions between the pyrenocarboxaldehyde and the desired thiosemicarbazide resulting in 1-pyrenocarboxaldehyde-N (3) -R-thiosemicarbazone compounds, H2PrR, where R = ethyl or cyclohexyl. Complexation reactions with the metal ions PdII and PtII were carried out with the H2PrR ligands. It was possible to obtain two main classes of complexes with different characteristics: i) monomeric complexes containing chlorido and triphenylphosphane ligands of the type [MCl(PPh3)(HPrR)] and (ii) tetramer complexes of the type [{M(PrR)}4], where M = PdII or PtII and R = etyl ou cyclohexyl. In both series the R group was modified by ethyl and cyclohexyl in order to investigate the correlation between lipophilicity and antiproliferative activity, while the pyrene group was attached to the ligands with the belief that a higher number of aromatic units would improve DNA intercalation and/or to be used as an intracellular probe. The characterization of the complexes involved techniques such as: elemental analysis, infrared and UV-Vis spectroscopy, conductimetry, nuclear magnetic resonance (1H and 13C NMR) and single crystal X-ray diffraction. The antiproliferative activity of the novel PdII and PtII compounds have been determined, several of them showed promising IC50 against ovarian cancer cells, and in many cases the observed activities are better than that of cisplatin. The data obtained indicate different effects for the metal centers (Pd vs Pt) and the ligands used (ethyl vs cyclohexyl). Uptake and cellular distribution studies proved that the palladium complex [PdCl(PPh3)(HPrCh)] achieved the cell nucleus. In order to verify possible biological targets, interaction with DNA, cell cycle and inhibition experiments of the topoisomerase IB (Top IB) enzyme were performed for some compounds. Cell cycle results showed an inhibition at the S and G2/M stages for the complexes [PdCl(PPh3)(HPrR)]. Overall, the results indicated the Top IB enzyme as one of the targets of the complexes. These preliminary results are quite promising and show that some of the complexes studied here can be used in cancer therapy in combination with other anticancer drugs.

The anti-tumor activity of platinum based drugs is mediated by their ability to attack DNA. Platinum complexes can alter the structure of DNA by modifying the bases, mainly guanines. The biological consequnces of such interactions are compromising replication and transcription. RNA polymerase complex can stall at a damaged site in DNA and mark the lesion for repair by proteins that are utilized to execute nucleotide excision repair, a pathway commonly associated with the removal of bulky DNA damage from the genome. This RNA polymerase-induced repair pathway is called transcription-coupled nucleotide excision repair. Main goal of this thesis was to study RNA polymerases tolerance of DNA damage by novel, biologically active platinum (II) complexes involving derivatives of aromatic cytokinines as the ligands; cis-[Pt(2-chloro-6-(4-methoxybenzylamino)-9-isopropylpurin)2Cl2](PR-001), cis-[Pt(2-chloro-6-(benzylamino)-9-isopropylpurin)2Cl2](PR-002 )and cis-[Pt(2-(3-hydroxypropylamino)-6-(benzylamino)-9-isopropylpurin)2Cl2](PR-005). DNA templates (constructs) that contain a single, site-specific DNA lesion and support transcription by human RNA polymerase II and bacteriophage T7 RNA polymerase were prepared. The method is making use of polymerase chain reaction (PCR) and biotin-streptavidin interactions and paramagnetic particles to purify the final product. Synthetic oligomers duplexes (75-mer, 56-mer and 15-mer) are ligated to 5´-biotin pCI-neo-G-lessT7 PCR fragment, the 15-mer is either unmodified or modified with a site-specific lesion of PR-005 and cisplatin. We also studied the inhibition of RNA polymerases activity on globally modified plasmid pCI-neo and pUC 19 by novel platinum complexes and cisplatin. We found that bifunctional adducts of complex PR-005 contrary to adducts of PR-001 and PR-002 effectively decrease amount of full lenght transcripts produced by both, human and bacterial RNA polymerases. This result can be explained by a sterical block, induced to DNA by intrastrand cross-link of PR-005 with bulky aromatic ligands.

Les télomères sont des structures spécifiques nucléoprotéiques localisées aux extrémités des chromosomes. Ils protègent les chromosomes contre la dégradation, les recombinaisons et les fusions et permettent qu’ils ne soient pas reconnus comme des cassures à l’ADN. Ils sont composés d'ADN télomérique, constitué de répétitions de la séquence TTAGGG, qui se prolonge par une extrémité 3’ simple brin, et de six protéines télomériques dont la protéine TRF2 qui sont indispensables au maintien de l’intégrité des télomères. Le brin riche en guanines est capable, en présence de cations monovalents, de se replier sur lui- même en une structure à quatre brins, la structure G-quadruplexe. Sa stabilisation par des ligands est une stratégie anti-tumorale car elle provoque des perturbations télomériques conduisant à la mort des cellules cancéreuses. Comme les télomères sont des séquences riches en guanines, ils peuvent aussi constituer une cible potentielle des complexes de platine. Notre objectif consiste à augmenter le ciblage des télomères en associant au sein de la même molécule, un ligand de structure G-quadruplexes qui reconnaitrait ces structures avec un atome de platine qui les bloquerait ensuite irréversiblement. La tolyl-terpyridine-Pt(II), (Pt-ttpy) a été conçue dans ce but. Elle stabilise et se fixe irréversiblement sur les structures G-quadruplexe in vitro. Nous avons analysé les perturbations télomériques induites par ce ligand de G-quadruplexes (Pt-ttpy) en comparaison avec des complexes qui ne stabilisent pas ces structures (terpyridine-Pt(II) ou Pt-tpy, et le cis-platine drogue anti-tumorale utilisée en chimiothérapie) et quantifié le nombre de complexes fixés au niveau des télomères. Nous avons travaillé sur deux lignées cancéreuses d’ovaire sensibles et résistantes au cis-platine (A2780 A2780-cis) et une lignée non-cancéreuse BJ-hTERT. Les complexes Pt-ttpy et Pt-tpy inhibent la prolifération cellulaire des cellules cancéreuses à des doses de l’ordre du µM et ne montrent aucune résistance croisée avec le cis-platine. Nos résultats obtenus par ChIP et immunofluorescence montrent sans ambiguïté que Pt-ttpy délocalise 50% de protéine TRF2 des télomères uniquement des cellules cancéreuses et augmente les dommages au niveau de l’ADN télomérique par rapport aux complexes qui ne sont pas des ligands de G-quadruplexes, sans pour autant induire un raccourcissement des télomères. Donc l’association d’un ligand de G-quadruplexes avec un atome de platine au sein d’une même molécule permet de cibler préférentiellement les télomères des cellules cancéreuses par rapport au complexe de platine seul. Cependant, les perturbations télomériques induites par Pt-ttpy n’ont pas été augmentées par rapport aux meilleurs ligands de G-quadruplexes connus. De façon intéressante, et pour la première fois dans la littérature, nous avons montré que nos deux complexes Pt-ttpy, Pt-tpy ciblent directement les télomères des cellules cancéreuses puisqu’ils s’y fixent. Ils augmentent la préférence de fixation à l’ADN télomérique/l’ADN génomique d’un facteur 15 par rapport au cis-platine. Cette préférence de fixation semble indépendante de la reconnaissance de structures G-quadruplexes mais semble plutôt dépendre de la nature des complexes de platine. D’autre part, à cause de la faible quantité de complexes retrouvée au niveau des télomères, leur fixation aux télomères ne peut être responsable, à elle seule, la délocalisation de TRF2, suggérant que le déplacement de TRF2 des télomères n’est pas dû un empêchement physique mais plutôt à une réponse biologique. Ainsi, nos travaux montrent que les molécules hybrides ligands de structure G-quadruplexes-Pt(II) sont une stratégie intéressante pour ciblage des télomères des cellules cancéreuses. Ceci ouvre la voie au développement de nouveaux complexes dont le facteur de préférence pour l’ADN télomérique et également la quantité de complexe fixée au niveau de l’ADN télomérique seraient augmentés par rapport à Pt-ttpy / Telomeres are specialized nucleoprotein complexes located at the end of chromosomes. They protect chromosomes from degradation, recombination and telomeric fusions and avoid them to be recognized as DNA breaks. They are composed of telomeric DNA consisting of repetitions of the sequence TTAGGG, which is extended by a 3 'single-stranded DNA, and of six telomeric proteins which TRF2 protein, that are essential to the maintenance of the integrity of telomeres. The guanine-rich strand is able to fold, in the presence of monovalent cations, in a four stranded structure, the G-quadruplexes. The stabilization of these structures is a promising anticancer strategy because it induces telomeric perturbations leading to cancer cell death. As telomeres are rich in guanines, they are potential targets for platinum complexes. Our aim is to increase the targeting of telomeres by associating within the same molecule, a ligand of G-quadruplex which stabilizes these structures with a platinum atom which then, will irreversibly block these structures. The tolyl-terpyridin-Pt(II) (Pt-ttpy) has been designed in this aim. It stabilizes and binds irreversibly to the G-quadruplex structures in vitro. We anlysed the telomeric perturbations induced by this G-quadruplex ligand (Pt-ttpy) in comparison with complexes which do not stabilize these structures (terpyridin-Pt(II) or Pt-tpy and cisplatin, an anti-tumor widely drug used in chemotherapy) and quantified the number of complexes bound to telomeres. We used two ovarian cancer cells lines, sensitive and resistant to cisplatin (A2780 and A2780-cis), and a non-cancer cell line (BJ-hTERT). Pt-ttpy and Pt-tpy inhibit cancer cell proliferation in doses at the µM range and show no cross-resistance with cisplatin. Our results, obtained by ChIP and immunofluorescence experiments, show that Pt-ttpy delocalize 50% of protein TRF2 from telomeres of cancer cells and increases the damage to telomeric DNA compared to the complexes that are not ligands of G quadruplexes, without inducing telomere shortening. Therefore, the association of a G-quadruplex ligand to a platinum atom within the same molecule allows to preferentially targeting telomeres of cancer cells compared to the platinum complex alone. However, telomeric perturbations induced by Pt-ttpy were not increased compared to the best known G-quadruplex ligands. Interestingly, and for the first time in the literature, we have shown that Pt-ttpy, Pt-tpy complexes directly target cancer cells since they bind irreversibly to them. They increase the preference of binding to telomeric DNA versus genomic DNA by a factor of 15 compared to cisplatin. This preference seems independent of the recognition of G-quadruplex structures but seems to depend on the nature of platinum complexes. On the other hand, because of the small amount of complexes bound to telomeres, their binding to telomeres cannot be at the origin, alone, of the delocalization of TRF2 from telomeres, suggesting that delocalization of telomeric TRF2 is not due to a physical impediment but rather to a biological response. Our work shows that the hybrid molecules G-quadruplex ligands-Pt (II) are an interesting strategy for targeting telomere of cancer cells. Therefore, it will be interesting to develop new complexes which would increase the preference for telomeric DNA and also the amount of platinum bound to telomeric DNA compared to Pt-ttpy

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The demand for protection of eyes and various types of optical sensors from laser-beam pulses has resulted in the search for optical limiting devices that have the property of being transparent at low intensity of light (normal light), but non-transparent towards high intensity (laser) light. This type of protection may be obtained by using an organic material that displays nonlinear optical (NLO) properties. Examples of NLO effects that can be used for optical limiting are reverse saturable absorption (RSA), two-photon absorption (TPA) and nonlinear refraction. The advantage of using compounds that show such NLO effects is that they can have very fast response and are self-activating, that is, there is no need for externally controlled switching to obtain optical limiting. In this work, several dialkynyl substituted thiophenes and some thiophenyl-alkynyl-platinum(II)-complexes were synthesized and tested for nonlinear absorption of light. A palladium-copper mediated coupling (Sonogashira coupling) was utilized for all reactions between terminal alkynes and aryl halides. Molecular orbital calculations were used in order to screen for suitable properties, such as the second hyperpolarizability, in compounds of interest. A quantitative structure-activity relationship (QSPR) study using a PLS approach were performed in order to identify important molecular electronic variables for optical limiting of organic compounds.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-12T17:47:09Z No. of bitstreams: 1 lucasfagundesesteves.pdf: 3341806 bytes, checksum: 01a9ea92db8351da3b0d30ea2a019200 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:53:28Z (GMT) No. of bitstreams: 1 lucasfagundesesteves.pdf: 3341806 bytes, checksum: 01a9ea92db8351da3b0d30ea2a019200 (MD5) / Made available in DSpace on 2016-07-13T16:53:28Z (GMT). No. of bitstreams: 1 lucasfagundesesteves.pdf: 3341806 bytes, checksum: 01a9ea92db8351da3b0d30ea2a019200 (MD5) Previous issue date: 2012-02-29 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Neste trabalho foram utilizadas metodologias teóricas para a descrição do mecanismo de ação de complexos binucleares de platina(II) do tipo 1,1/c,c e 1,1/t,t. Inicialmente foi elucidada a influência do arranjo conformacional da cadeia espaçadora na estabilidade de complexos binucleares, através da construção de um parâmetro topológico chamado grau de distorção (λ). Para a construção do parâmetro λ, foi realizada uma busca conformacional no nível PM3 utilizando o método de Monte Carlo (MC) para o ligante desses complexos binucleares, a molécula de 1,6-hexanodiamina. O parâmetro λ, correlaciona-se linearmente com a energia PM3 dos confôrmeros obtidos, aumentando o seu valor à medida que a energia total diminui. O parâmetro λ correlaciona-se fortemente com as energias relativas em fase gás ( ) e em fase aquosa ( ) após a inclusão das esferas de coordenação metálica dos complexos 1,1/c,c e 1,1/t,t em determinadas conformações e posterior otimização no nível DFT com o funcional B3LYP e o conjunto de funções de base 6-31+G(d,p) para todos os átomos, exceto para a platina, a qual foi tratada com o pseudopotencial LANL2DZ. As reações de hidrólise dos complexos 1,1/c,c e 1,1/t,t foram estudadas em fase gás no nível B3LYP/6-31+G(d,p)/LANL2DZ e em fase aquosa com os modelos PCM/UAHF e PCM/Bondi. As constantes de velocidade calculadas para a reação direta em fase aquosa resultaram em valores muito próximos daqueles determinados experimentalmente, os quais são da ordem de 10-5s-1, para os complexos 1,1/c,c e 1,1/t,t. Durante esta dissertação também foi avaliada a influência da conformação na primeira barreira de hidrólise de complexos 1,1/c,c, mostrando que algumas conformações, que em um primeiro momento são instáveis, podem gerar barreiras de reação menores do que as conformações mais estáveis. Foram estudados os mecanismos de coordenação de complexos 1,1/c,c com a guanina em fase gás e fase aquosa no mesmo nível de teoria utilizado durante a etapa de hidrólise. / In this work, theoretical methods were used to describe the action mechanism of binuclear platinum(II) complexes named 1,1/c,c and 1,1/t,t. Initially, the influence of the conformational arrangement of the diamine chain on the stability of binuclear complex was elucidated, through the construction of a new topological parameter called distortion degree λ. In order to create the λ parameter, were performed a conformational search at PM3 level of theory using Monte Carlo (MC) method only for the ligand of these binuclear complexes, the 1,6-hexanediamine molecule. The λ parameter linearly correlates with the PM3 energy of the conformers, increasing its value, as the total energy decreases. The λ parameter has a strong correlation with the relative energies in gas phase ( ) and aqueous phase ( ) after the inclusion of the metallic coordination sphere of the 1,1/c,c and 1,1/t,t complexes in some specific conformations. Subsequent optimization has been carried out at DFT approach with the B3LYP functional and the 6-31+G(d,p) Pople’s basis set for all atoms, except for platinum, which was treated with LANL2DZ pseudopotential. The hydrolysis reaction of 1,1/c,c and 1,1/t,t complexes were studied in gas phase at B3LYP/6-31+G(d,p)/LANL2DZ level and in aqueous phase with the PCM/UAHF and PCM/Bondi model. The calculated rate constants for the forward reaction in aqueous phase lead to values very close to those experimentally resolute, which are about 10-5s-1 for the 1,1/c,c and 1,1/t,t complexes. During this study the influence of conformation on the first hydrolysis barrier of 1,1/c,c complex were also evaluated, showing that some conformations, which at the first moment were considerable unstable, can generate lower reaction barriers than the most stable conformations. The coordination mechanism of 1,1/c,c complex with guanine in gas and aqueous phase at the same level of theory used during the hydrolysis step were also studied and compared with literature.

Au cours de ce travail, nous avons démontré l’apport que pouvait avoir le développement de nouveaux complexes chiraux de platine et d’or pour la catalyse asymétrique et pour la découverte de nouvelles réactions de cycloisomérisation d’énynes. Dans la première partie, de nouveaux complexes de platine chiraux ont été utilisés pour effectuer la première étude systématique de la réaction de cycloisomérisation d’énynes 1,5 hydroxylées. Les composés bicycliques correspondant ont été obtenus avec de bons rendement et jusqu’à 81% d’excès énantiomérique. Par la suite, de nouveaux complexes chiraux d’or, possédant un ligand phosphahélicène ont permis d’obtenir de très bons résultats dans des réactions de cycloisomérisation d’énynes 1,6 (jusqu’à 86% ee). Des variations structurales des hélices phosphorées ont ensuite été effectuées, en changeant notamment le groupement P-menthyle par un substituant P-isopinocampheyle. Si les complexes d’or correspondant n’ont pas permis de donner des résultats important en catalyse, cela a permis d’avoir une meilleure connaissance de nos catalyseurs, et des substitutions nécessaires à de bonnes inductions asymétriques. D’autre part, ces nouveaux catalyseurs semblent donner des résultats prometteurs dans des réactions d’organocatalyse asymétrique. Enfin, l’exploration de la chimie des phosphéniums N-hétérocycliques comme ligands du platine a permis de se rendre compte de la faible stabilité de ces espèces, mais surtout des activités catalytiques très intéressantes que pouvaient obtenir ces catalyseurs dans des réactions de cycloisomérisation. Ce travail préliminaire démontre la « preuve de concept », qui ne demande qu’à être continué à l’avenir. / In this work, we have carried out the first systematic investigations on the enantioselective transition metal-promoted cycloisomerizations of 1,5-enynes with hydroxyl functions at their propargylic positions. These experiments have highlighted a series of platinacyclic NHC-complexes afforded bicyclo[3.1.0]hexanones in up to 81% enantiomeric excess. In the second part of our work we have prepared both known and new phosphahelicenes via the oxidative photocyclization of olefins suitably made from phosphindole building blocks. We have demonstrated that this synthetic method allows modulation of the phosphahelicene structure. Gold(I) complexes have been prepared then from these phosphahelicenes. These complexes have been evaluated in the challenging field of the gold-catalyzed enantioselective cycloisomerizations of enynes. In the cycloisomerization of NTs tethered 1,6-enynes, we could obtain very high catalytic activity and good enantioselectivity, with up to 81% ee, by using the P-menthyl-substituted helicenes as chiral ligands. The cycloisomerization of 1,6-dien-8-ynes, which afforded bi- or tricyclic compounds in one step, at room temperature, in high yields and excellent enantiomeric excesses (up to 86% ee). Thus, we have demonstrated that phosphahelicenes-gold complexes represent a new class of efficient catalysts, which complements the few chiral gold catalysts known so far. The chiral phosphahelicenes above have been evaluated briefly in a totally different field, that is nucleophilic organocatalysis. The trivalent phosphahelicenes proved able to promote the enantioselective [3+2] cyclizations between olefins and allenes, giving cyclopentene derivatives in excellent enantiomeric excesses (up to 96% ee). Finally, we have investigated the use of N-heterocyclic phospheniums as ligands in transition metal catalysis, starting from platinum promoted cycloisomerizations as the model reactions. In doing these challenging, exploratory experiments, we have noticed a moderate stability of the few platinum-NHP complexes prepared so far. Nevertheless, the cationic Pt(0) complex (mesNHP)Pt(PPh₃)₂⁺OTf could be generated in situ. It displayed moderate but significant catalytic activity in the cycloisomerization of a 3-hydroxy-1,5-enyne (51% isolated yield). These experiments afford a proof-of-concept, but additional work is required to identify the most suitable metal/NHPs pairs leading to stable and efficient pre-catalysts. The cationic nature of the NHP ligands might open totally new perspectives in organometallic catalysis. Further studies on this topic will be carried out in our group in the near future.

La cycloaddition 1,3-dipolaire catalysée par le cuivre(I) entre un azoture et un alcyne (CuAAC), réaction de « chimie click » par excellence, suscite un grand intérêt en raison de son efficacité et de sa versatilité. L'objectif premier de cette thèse est d'appliquer cette réaction pour l'élaboration de structures 1,2,3-triazoles fonctionnalisées, en vue d'obtenir des ligands jouant le rôle de « pince à platine ». Les complexes de platine biologiquement actifs rapportés sont de type mono- ou bi-nucléaire et comportent un ou deux cycles triazole. Les complexes obtenus ont fait l'objet d'une étude in vitro d'interaction avec des nucléosides et de l'ADN soit sous forme d'hairpin (épingle à cheveux) soit sous forme plasmidique. Nos complexes ont montrés une réactivité similaire à celle du cisplatine, qui est la métallodrogue de référence. En parallèle, nous présentons les propriétés catalytiques et biologiques de complexes cuivre(I)-NHC (Carbène N-Hétérocyclique), dérivés du [CuCl(SIMes)], mis au point par Nolan et al. Dans un premier temps, un criblage d'activités catalytiques a été réalisé avec divers additifs aromatiques azotés afin d'améliorer l'efficacité de la CuAAC. Dans un deuxième temps, la cytotoxicité et l'activité antitumorale du complexe [CuCl(SIMes)] ont été considérées sur plusieurs lignées cellulaires. Nous rapportons ici, le premier exemple de cuivre(I)-NHC biologiquement actif, présentant une activité largement supérieure à celle du cisplatine. Enfin, la réactivité de ce complexe avec de l‟ADN plasmidique a été évaluée in vitro et nous rapportons sa capacité à couper l‟ADN. / The copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC), a “click chemistry” reaction, is of a great interest thanks to its efficiency and versatility. The present work aims to use this reaction for the elaboration of new functionalised 1,2,3-triazole, as “pincer ligand” to platinum. We have synthesized mono- or binuclear platinum anticancer complexes that contain one or two triazole cycles. These complexes were subject to in vitro tests, in order to investigate the interactions they can establish with both nucleosides and DNA. The results reveal a reactivity similar to cisplatin, the reference metallodrug. In parallel, we present the catalytic and biological properties of copper(I)-NHC complexes, like [CuCl(SIMes)] developed by Nolan et al. At first, a screening of the catalytic activity was realized with diverse nitrogen aromatics additives in order to improve the CuAAC efficiency. Secondly, the cytotoxicity and antitumoral activity of [CuCl(SIMes)] were considered on various cancer cell lines. We report here, the first example of a biologically active copper(I)-NHC, this complexe exhibiting a superior activity than cisplatin. Finally, the reactivity of this copper(I)-NHC with DNA was evaluated in vitro and highlights its capacity to cleave DNA.