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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Estudo de complexos de ferro e de cobre com a base de Shiff 3-Meosalen e ligantes de relev?ncia biol?gica

Paiva, Anallicy Santos de 13 January 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-05T22:05:48Z No. of bitstreams: 1 AnallicySantosDePaiva_DISSERT.pdf: 3646854 bytes, checksum: b8d729674436c7b1a04f25e58226e9b1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-15T22:24:06Z (GMT) No. of bitstreams: 1 AnallicySantosDePaiva_DISSERT.pdf: 3646854 bytes, checksum: b8d729674436c7b1a04f25e58226e9b1 (MD5) / Made available in DSpace on 2016-02-15T22:24:06Z (GMT). No. of bitstreams: 1 AnallicySantosDePaiva_DISSERT.pdf: 3646854 bytes, checksum: b8d729674436c7b1a04f25e58226e9b1 (MD5) Previous issue date: 2015-01-13 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / O objetivo estabelecido para este trabalho foi sintetizar e caracterizar novos complexos de ferro e de cobre com a base de Schiff 3-MeOsalen e ligantes de relev?ncia biol?gica, cujas f?rmulas s?o [Fe(3-MeOsalen)NO2], [Fe(3-MeOsalen)(etil2-dtc)], [Fe(3-MeOsalen)NO] e Na[Cu(3-MeOsalen)NO2]. Os compostos foram caracterizados atrav?s da espectroscopia vibracional na regi?o do infravermelho (IV) e da espectroscopia eletr?nica na regi?o do ultravioleta e vis?vel (Uv-Vis). A partir das an?lises dos espectros de infravermelho, comprovou-se a forma??o dos complexos precursores, evidenciada pelas altera??es nas frequ?ncias de vibra??o ?(C=N) e ?(C-O) e pelo surgimento de modos vibracionais metal-oxig?nio e metal-nitrog?nio. Para os nitro complexos de ferro e cobre observaram-se ?(NO2)ass em torno de 1300 cm-1 e ?(NO2)sim em 1271 cm-1 , indicando que a coordena??o se faz via ?tomo de nitrog?nio. O espectro do complexo [Fe(3-MeOsalen)(etil2-dtc)] exibiu duas bandas, o ?(C-NR2) em 1508 cm-1 e ?(C-S) em 997 cm-1 , pertinentes a modos vibracionais de coordena??o do ligante na forma bidentada. Para o complexo [Fe(3-MeOsalen)NO] foi observado uma nova banda intensa em 1670 cm-1 referente ao ?(NO). Com os espectros eletr?nicos, a forma??o dos complexos foi evidenciada pelos deslocamentos das bandas de transi??es intraligantes e pelo surgimento de novas bandas, como a LMCT (p? Cl- ? d?* Fe3+) no [Fe(3-MeOsalen)Cl] e a d-d no [Cu(3-MeOsalen)H2O]. J? para o [Fe(3-MeOsalen)NO2], destacou-se a aus?ncia da banda LMCT presente no complexo precursor enquanto para o Na[Cu(3-MeOsalen)NO2] constatou-se o deslocamento hipsocr?mico da banda d-d em 28 nm. O espectro eletr?nico do [Fe(3-MeOsalen)(etil2-dtc)] apresentou deslocamentos da banda LMCT e altera??es nas transi??es intraligantes. No que se refere ao [Fe(3-MeOsalen)NO], evidenciou-se transi??es intraligantes em regi?es mais energ?ticas, proveniente do forte car?ter ? receptor do NO e uma banda MLCT, da transi??o d?Fe(II)??*(NO). / The goal set for this work was to synthesize and to characterize new iron and copper complexes with the Schiff base 3-MeOsalen and ligands of biological relevance, whose formulas are [Fe(3-MeOsalen)NO2], [Fe(3-MeOsalen)(etil2-dtc)], [Fe(3-MeOsalen)NO] and Na[Cu(3-MeOsalen)NO2]. The compounds were characterized by vibrational spectroscopy in the infrared region (IV) and Electronic spectroscopy in the ultraviolet and visible region (Uv-Vis). From the analysis of infrared spectra, they proved to formation of precursor complexes, as evidenced by changes in the vibrationals frequencies ?(C=N) e ?(C-O) and the emergence of vibrationals modes metal-oxygen and metal-nitrogen. For nitro complexes of iron and copper were observed ?(NO2)ass around 1300 cm-1 e ?(NO2)sim in 1271 cm-1 , indicating that the coordination is done via the nitrogen atom. The complex spectrum [Fe(3-MeOsalen)(etil2-dtc)] exhibited two bands, the ?(C-NR2) in 1508 cm-1 e ?(C-S) in 997 cm-1 , the relevant vibrational modes of coordinating ligand in the bidentate form. For the complex [Fe(3-MeOsalen)NO] was observed a new intense band in 1670 cm-1 related to the ?(NO). With the electronic spectra, the formation of complexes was evidenced by shifts of bands intraligands transitions and the emergence of new bands such as LMCT (p? Cl- ? d?* Fe3+) in [Fe(3-MeOsalen)Cl] and the d-d in [Cu(3-MeOsalen)H2O]. As for the [Fe(3-MeOsalen)NO2] has highlighted the absence of LMCT band present in the precursor complex as for the [Cu(3-MeOsalen)NO2] found that the displacement of the band hipsocr?mico d-d on 28 nm. The electronic spectrum of [Fe(3-MeOsalen)(etil2-dtc)] presented LMCT band shifts and changes in intraligantes transitions. With regard to [Fe(3-MeOsalen)NO], revealed a more energetic transitions intraligands regions from the strong character ? receiver NO and MLCT band of transition d?Fe(II)??*(NO).
12

S?ntese e caracteriza??o de complexos de base de schiff com n?quel (ii) ancorados no material mesoporoso SBA-15

Maia, Danielle de Oliveira 23 July 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-30T22:35:16Z No. of bitstreams: 1 DanielleDeOliveiraMaia_TESE.pdf: 2480138 bytes, checksum: 11e89b7c4d42403108c704fd453975d5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-01T20:04:06Z (GMT) No. of bitstreams: 1 DanielleDeOliveiraMaia_TESE.pdf: 2480138 bytes, checksum: 11e89b7c4d42403108c704fd453975d5 (MD5) / Made available in DSpace on 2016-06-01T20:04:06Z (GMT). No. of bitstreams: 1 DanielleDeOliveiraMaia_TESE.pdf: 2480138 bytes, checksum: 11e89b7c4d42403108c704fd453975d5 (MD5) Previous issue date: 2015-07-23 / SBA-15 s?o materiais mesoporosos, que possuem uma rede de canais e poros de tamanho bem definido na escala nanom?trica, al?m de outras caracter?sticas, tais como, elevada estabilidade t?rmica e ?rea superficial. Essa arquitetura particular de poros torna esses materiais promissores na ?rea de ancoramento de uma variedade de compostos na matriz da s?lica resultando em aplica??es nas diversas ?reas, dentre elas, na cat?lise. Nesse trabalho, foram sintetizados complexos de Base de Schiff com n?quel (II) para serem ancorados na SBA-15 funcionalizada com 3-cloropropiltrimet?xisilano realizando um estudo da estabilidade t?rmica desses compostos. Ap?s a s?ntese dos complexos, estes foram caracterizados por an?lise elementar (CHN), ponto de fus?o, condutividade, susceptibilidade magn?tica, espectroscopia de absor??o na regi?o do UV-vis?vel, espectroscopia de absor??o na regi?o do infravermelho e an?lises t?rmicas (TG/DTG). A an?lise elementar sugere que os complexos apresentam as seguintes f?rmulas qu?micas gerais: [Ni(C18H19N3O2)].2CH3COO.H2O, [Ni(C20H23N3O2)(2Cl)].2H2O, [Ni(C19H20N3O2)(2Cl)].3H2O, sendo L1= C18H19N3O2, L2= C20H23N3O2, L3 = C19H20N3O2. Na espectroscopia de absor??o na regi?o do UV - vis?vel e infravermelho dos complexos foi evidenciada a coordena??o metal - ligante. Ap?s caracteriza??o dos complexos, estes foram ancorados no material mesoporoso. A caracteriza??o desses materiais foi realizada por difra??o de raios - X, fluoresc?ncia de raios - X, adsor??o e dessor??o de N2, espectroscopia de absor??o na regi?o do infravermelho e an?lises t?rmicas (TG/DTG). No DRX foram observados tr?s picos principais de difra??o, cujos ?ndices de Miller s?o (100), (110) e (200), mostrando que mesmo ap?s a ancoragem, os materiais mesoporosos n?o perderam suas caracter?sticas estruturais. As porcentagens dos elementos (n?quel, cloro e s?lica) encontrados nos materiais atrav?s da an?lise de fluoresc?ncia de raios - x mostraram que os complexos foram ancorados nos poros da s?lica. Atrav?s da adsor??o e dessor??o de N2, foram observadas que os materiais apresentaram isoterma do tipo IV e histerese do tipo H1 caracter?sticos dos materiais mesoporos. Na espectroscopia de absor??o na regi?o do infravermelho, os materiais ancorados apresentaram bandas caracter?sticas dos ligantes (Base de Schiff) e da s?lica evidenciando o sucesso da ancoragem. Na an?lise t?rmica, foram observadas a decomposi??o de ?gua adsorvida, ?gua coordenada, aminas, arom?ticos, ligantes, cloropropiltrimet?xisilano e o aumento na estabilidade t?rmica das s?licas ancoradas com complexos comparado ao complexo livre. / SBA-15 are mesoporous materials, having a network of channels and well defined pore size in the nanometer range, as well as, other features such as high thermal stability and surface area. This particular pore architecture makes these promising materials in the anchoring area of a variety of compounds in the silica matrix resulting in applications in various fields, among them, in catalysis. In this work, complexes were synthesized Schiff base with nickel (II) to be anchored in the functionalized SBA-15 3 ? chloropropyltrimethoxysilane and a study of the thermal stability of these compounds. After synthesis of the complexes, they were characterized by elemental analysis (CHN), melting point, conductivity, magnetic susceptibility, absorption spectroscopy in the UV-visible region absorption, spectroscopy in the infrared region and thermal analysis (TG/DTG). Elemental analysis suggests that the complexes have the general formula chemical: [Ni(C18H19N3O2)].2CH3COO.H2O, [Ni(C20H23N3O2)(2Cl)].2H2O, [Ni(C19H20N3O2)(2Cl)].3H2O, and L1= C18H19N3O2, L2= C20H23N3O2, L3 = C19H20N3O2. In absorption spectroscopy in UV - visible and infrared complexes was evidenced the coordination metal - ligand. After characterization of the complexes, confirming the metal - ligand coordination, they have been anchored in the mesoporous material. The characterization of these materials were made by x- ray diffraction, x- ray fluorescence, N2 adsorption and desorption spectroscopy, the infrared spectroscopy and thermal analysis (TG/DTG). XRD analysis revealed three main diffraction peaks, whose Miller indices are (100), (110) and (200), showing that even after the anchoring, the mesoporous materials do not lose their structural characteristics. The percentages of the elements (nickel chloride and silica) found in the anchored materials through the x-ray fluorescence analysis showed that the complexes were anchored in the pores of the silica. Through adsorption and desorption of N2, we observed that the materials presented isotherm type IV and type H1 hysteresis characteristic of mesoporous materials. In the infrared spectroscopy, the materials showed characteristic bands of ligands (Schiff base) and silica demonstrating the success of the anchor. In the thermal analysis (TG/DTG), there were observed the decomposition of adsorbed water, coordinated water, amines, aromatics, ligands, chloropropyltrimethoxysilane and an increase in thermal stability (removal of ligand) of silicas anchored [Ni(L1)]SBA-15, [Ni(L2)SBA-15 and [Ni(L3)SBA-15 compared of free complexes, showing successful anchoring of complex molecular sieve.
13

S?ntese e caracteriza??o de complexos de cobre (II) com ligantes vanil?ides

Oliveira, Aim?e Ataide de 20 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-14T21:09:09Z No. of bitstreams: 1 AimeeAtaideDeOliveira_DISSERT.pdf: 5104829 bytes, checksum: 9b498108ee9e964f88f190ee1fb53c10 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-15T21:31:12Z (GMT) No. of bitstreams: 1 AimeeAtaideDeOliveira_DISSERT.pdf: 5104829 bytes, checksum: 9b498108ee9e964f88f190ee1fb53c10 (MD5) / Made available in DSpace on 2017-03-15T21:31:12Z (GMT). No. of bitstreams: 1 AimeeAtaideDeOliveira_DISSERT.pdf: 5104829 bytes, checksum: 9b498108ee9e964f88f190ee1fb53c10 (MD5) Previous issue date: 2016-07-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo deste trabalho ? contribuir com o desenvolvimento da qu?mica de coordena??o do sistema cobre-fenantrolina, atrav?s da s?ntese e caracteriza??o de novos complexos met?licos do tipo [Cu(phen)(L)2] onde L refere-se a ligantes derivados da vanilina. Atrav?s da caracteriza??o dos complexos [Cu(phen)(asv)2], [Cu(phen)(asvred)2] e [Cu(phen)(dhz)2], por infravermelho, foram identificados que os ligantes derivados da vanilina encontram-se coordenados ao centro met?lico de forma bidentada atrav?s dos grupos vanil?ides e que a fenantrolina ? mantida na esfera de coordena??o do metal. Os espectros eletr?nicos dos complexos, obtidos em acetonitrila, apresentaram bandas intraligantes da fenantrolina com elevada absortividade molar, bandas intraligantes t?picas do ligante vanil?ide L, com deslocamentos hipsocr?micos e batocr?micos em rela??o ao ligante n?o coordenado e ainda transi??es d-d, as quais reafirmam a forma??o do complexo. A identifica??o da fluoresc?ncia do ligante do ligante asv foi realizada tanto no estado s?lido quanto em solu??o de acetonitrila. O espectro de fluoresc?ncia deste composto apresentou uma banda de emiss?o em 506 nm, que corresponde ? regi?o da cor verde, quando da excita??o na regi?o no ultravioleta. Os potenciais de redu??o do Cu2+/1+ nos complexos [Cu(phen)(asv)2], [Cu(phen)(asvred)2] e [Cu(phen)(dhz)2] foram observados, respectivamente, em - 62, - 45 e - 126 mV vs Ag/AgCl. Os valores obtidos encontram-se em uma faixa de potencial considerada adequada (261 a -523 mV) para que o cobre, quando reduzido a Cu1+, seja capaz de gerar esp?cies reativas de oxig?nio em meio biol?gico. / The objective of this work is to contribute to the development of coordination chemistry of copper-phenanthroline system, through the synthesis and characterization of new metal complexes of the type [Cu(phen)(L)2] where L refers to vanillin derivatives ligands. Through characterization of the complex [Cu(phen)(asv)2], [Cu(phen)(asvred)2] and [Cu(phen)(dhz)2], by infrared, it was identified that the binders derived from vanillin are coordinated to the metal center bidentately through the vanilloid groups and the phenanthroline is maintained in the coordinating sphere of the metal. The electron spectra of the complexes, obtained in acetonitrile, presented intraligant bands of phenanthroline with high molar absorptivity, intraligant bands typical of the vanilloid ligand L, with hypochromic and bathochromic displacements in relation to the uncoordinated ligand and also d-d transitions, which reaffirm the formation of the complex. The fluorescence identification of the ligand of the asv ligand was performed both in the solid state and in acetonitrile solution. The fluorescence spectrum of this compound had an emission band at 506 nm, which corresponds to the green color region, when excited in the ultraviolet region. The potential for reducing the Cu2+/1+ in the complex, [Cu(phen)(asv)2], [Cu(phen)(asvred)2] and [Cu(phen)(dhz)2], were observed, respectively, - 62, - 45 and - 126 mV vs. Ag / AgCl. The values obtained are in a potential range considered appropriate (261 to -523 mV) for the covers, when reduced to Cu1+, is capable of generating reactive oxygen species in a biological environment.
14

Síntese, caracterização e avaliação da atividade antituberculose de complexos de prata e zinco com a base de Schiff N,N´-bis(tiofenil-2-metilideno)etano-1,2-diamina

Silva, Silvioney Augusto da 24 January 2014 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-03T12:13:21Z No. of bitstreams: 1 silvioneyaugustodasilva.pdf: 3241038 bytes, checksum: d4f2b4d15c91d1718bc8150d6be6d119 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:23:41Z (GMT) No. of bitstreams: 1 silvioneyaugustodasilva.pdf: 3241038 bytes, checksum: d4f2b4d15c91d1718bc8150d6be6d119 (MD5) / Made available in DSpace on 2017-05-13T13:23:41Z (GMT). No. of bitstreams: 1 silvioneyaugustodasilva.pdf: 3241038 bytes, checksum: d4f2b4d15c91d1718bc8150d6be6d119 (MD5) Previous issue date: 2014-01-24 / No presente trabalho a base de Schiff, N,N’-bis(tiofenil-2-metilideno)etano1,2-diamina (BNH), foi obtida a partir da reação de condensação entre etilenodiamina (en) e 2-tiofenocarboxaldeído (TCA) usando a proporção molar 1:2 (en:TCA). Dois novos complexos de prata(I) com BNH foram preparados reagindo BNH:AgNO3. Quando a proporção molar de 1:1 (M:L) foi usada, o complexo polimérico [Ag(BNH)NO3]n foi obtido, onde os íons Ag(I) são coordenados por 2 N (grupo imina) de dois ligantes diferentes e um oxigênio do grupo nitrato. Quando a proporção molar de 1:2 (M:L) foi usada um complexo monomérico e quelato - [Ag(BNH)2]NO3 foi obtido. Neste complexo os íons prata(I) são coordenados por 4 N (grupo imina) de dois ligantes. Da mesma forma, complexos de zinco(II) também foram testados, mas as reações entre o BNH e ZnCl2 em 1:1 ou 1:2 (M:L) resultam no mesmo complexo formulado como [Zn(Cl)2(BNH)], onde o BNH se coordena ao íon Zn(II) pelos átomos de N (imina) e dois íons cloro completam a tetracoordenação em torno do íon zinco(II). Os compostos foram caracterizados por análises elementar (C, H, N) e térmica (TG/DTA), técnicas espectroscópicas de IV, Raman, Ressonância Magnética Nuclear e difração de raios X por monocristal e policristais. Além dos dados estruturais, analíticos, e espectroscópicos, foram realizados estudos biológicos. As propriedades antibacterianas e citotóxicos do BNH e de seus três complexos metálicos foram testadas com base na atividade AntiMBT e IC50 utilizando células VERO. Além disso, dois ligantes – N,N’-bis(tiofenil2-metil)-etano-1,2-diamina (obtido pela redução do BNH) e seu derivado cloridrato, foram sintetizados e parcialmente caracterizados. Um sal de ouro(III) também foi obtido e caracterizado por simples reação entre o cloridrato da diamina e o sal K[AuCl4]. / In the present work the Schiff base, N,N’-bis(thiophenyl-2-methylidene) ethane-1,2-diamine (BNH), was obtained from condensation reaction between ethylenediamine (en) and 2- thiophenecarboxaldehyde (TCA) using molar ratio1:2 (en:TCA). Two new silver(I) complexes with BNH were prepared by reacting BNH:AgNO3. When 1:1 molar ratio (M:L) was used, the polymeric complex [Ag(BNH)NO3]n is obtained where Ag(I) ions are coordinated by 2 N (imine group) from two different ligands and one oxygen from nitrate group. When 1:2 molar ratio (M:L) is used a monomeric and chelated complex – [Ag(BNH)2]NO3 was obtained. In this complex silver(I) ions are surrounded by 4 N (imine group) from two ligands. In the same way, the zinc(II) complexes were also tested, but the reactions between the BNH and ZnCl2 in 1:1 or 1:2 (M:L) result in the same complex formulated as [Zn(Cl)2(BNH)], where BNH is coordinated to Zn(II) ions by N (imine) and two chlorine ions complete the tetracoordination around zinc(II) ions. The compounds were characterized by elemental (C, H, N) and thermal analyzes (TG/DTA), IR, Raman, and Nuclear Magnetic Resonance spectroscopic techniques and X rays diffraction - monocrystal and powder. Besides the analytical, spectroscopic and structural data, the biological studies were performed. The antibacterial and cytotoxic properties of BNH and its three metal complexes were tested based on the activity Anti-MBT and IC50 using VERO cells. In addition, two ligands – N,N’-bis(thiophenyl-2-methyl)ethane-1,2-diamine (obtained by BNH reduction) and its hydrochloric derivative were synthesized and partially characterized. A gold(III) salt was also obtained and characterized by simple reaction between the diamine‘s hydrochloride and K[AuCl4] salt.
15

Synthèse, caractérisation et bioactivité de ligands issus de bases de Schiff dérivées de dithiocarbazate et de leurs complexes métalliques / Synthesis, characterization and bioactivites of dithiocarbazate Schiff base ligands and their metal complexes

Low, May Lee 09 July 2014 (has links)
Il y a de nos jours un besoin urgent de découvrir de nouveaux médicaments pour relever le défi de la multirésistance dans le traitement des infections bactériennes et le cancer. Dans cette perspective, des bases de Schiff dérivées de dithiocarbazates et leurs complexes métalliques correspondants sont des candidats intéressants puisqu'ils peuvent être facilement synthétisés et permettent une grande diversité de coordination. Dans cette étude, des complexes tetradentes et bidente ont été préparés. Les ligands et complexes synthétisés ont été entièrement caractérisés par différentes méthodes spectroscopiques et physico-chimiques dans le solide et en solution. L'activité antibactérienne de ces complexes a ensuite été étudiée et a permis de sélectionner un complexe " leader " (plus efficace, stable et fonctionnalisable). Ce complexe a alors été modifié afin d'augmenter sa stabilité en milieux biologique, sa solubilité dans l'eau ainsi que son activité. Il a été conjugué avec différentes entités : des peptides pénétrants, un polyéthylène glycol (PEG) et un peptide inhibiteur des pompes d'efflux bactériennes. Ces complexes ont montré une remarquable activité antibactérienne sur neuf souches de bactéries Gram-positives et Gram-négatives et en particulier, ils se sont avérés très efficaces contre S.aureus. L'activité anti-cancéreuse des complexes non-conjugués a également été étudiée et les complexes de cuivre sélectionnés et testés sur des cellules de cancer du sein ont montré une cytotoxicité élevée. Ceci met en évidence la pertinence d'utiliser les complexes métalliques, pour à la fois stabiliser les ligands et générer des composés plus actifs. / There is an urgent need to discover new drugs with novel mechanisms of action, higher activity and improved selectivity to address the severe challenge of multidrug resistance in treating bacterial infections and cancer. In view of this, Schiff bases derived from S-substituted dithiocarbazate and their corresponding metal complexes with a plethora of potentially exciting biological activities and coordination chemistry are attractive candidates. Metal complexes of tetradentate NNSS and bidentate NS ligands have been prepared. The compounds were fully characterized with various physico-chemical and spectroscopic methods in solution and solid state. Conjugation of the most promising antimicrobial compound to various moities (polyarginine, polyethylene glycol (PEG) and an bacterial efflux pump inhibitor) was achieved to prepare improved therapeutic agents. The nanoarginines (R9) derivatives showed the most encouraging synergistic effect upon conjugation and complexation to copper ion with enhanced water solubility, bacteria cell membrane permeability and bioactivity. The Cu(II) R9 derivatives possess remarkable antibacterial activity against a wide spectrum of bacteria and in particular, highly efficacious against S. aureus. This show that the conjugation of polyarginine to dithiocarbazate compounds can greatly influence their therapeutic potential. Cytotoxic assay was also carried out for selected non-conjugated compounds. All the selected Cu(II) complexes assayed against breast cancer cells lines exhibited good cytotoxicity. This work highlights the relevance of the strategy that consists of using metal complexes to stabilize the ligands and improve their bioactivity.
16

Efeitos dos complexos de níquel e platina derivados de base de Schiff no câncer de bexiga urinária não-músculo invasivo / Effects of nickel and platinum complexes derived from Schiff base on non–muscle invasive urinary bladder cancer

Matsumoto, Mirian Yoshiko 30 May 2017 (has links)
Submitted by Mirian Yoshiko Matsumoto (mirian_matsumoto@hotmail.com) on 2018-09-13T03:42:01Z No. of bitstreams: 1 Tese de Doutorado BGA Mirian Matsumoto.pdf: 5590776 bytes, checksum: 35a18a86dcfd4a42e7e9c40dbce00a94 (MD5) / Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2018-09-14T16:51:20Z (GMT) No. of bitstreams: 1 matsumoto_my_dr_bot.pdf: 5590776 bytes, checksum: 35a18a86dcfd4a42e7e9c40dbce00a94 (MD5) / Made available in DSpace on 2018-09-14T16:51:20Z (GMT). No. of bitstreams: 1 matsumoto_my_dr_bot.pdf: 5590776 bytes, checksum: 35a18a86dcfd4a42e7e9c40dbce00a94 (MD5) Previous issue date: 2017-05-30 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O câncer de bexiga (CB) é a segunda malignidade geniturinária mais comum. A maioria (75%) dos CBs são primeiramente diagnosticados como não-músculo invasivos (CBNMIs) nos estádios Ta, T1, e carcinoma in situ (CIS). Atualmente, o tratamento mais utilizado contra CBNMIs envolve a imunoterapia com Bacillus Calmette-Guérin (BCG) associada à ressecção transuretral (RTU). No entanto, a utilização de BCG pode causar graves efeitos colaterais e está associada com uma elevada taxa de recorrência após o tratamento. Por conseguinte, várias abordagens têm sido investigadas, incluindo o desenvolvimento de novas moléculas, assim como a melhoria da terapia com medicamentos convencionalmente utilizados no tratamento de tumores e a incorporação de sistemas de carreamento de fármacos. Considerando o uso de novas moléculas, complexos metálicos derivados de bases de Schiff (BSs) são compostos versáteis que apresentam atividade antitumoral, fornecendo assim novas perspectivas para a terapia do CBNMI. Em relação ao carreamento de fármacos, ao longo dos últimos anos, carreadores lipídicos nanoestruturados (CLNs) têm atraído considerável interesse como veículos alternativos para produtos farmacêuticos antitumorais. Assim, com o intuito de adquirir maior conhecimento a respeito da química dos complexos derivados da BS N-Salicilideno anilina (Salan) e também seus efeitos na progressão do CBNMI, esta tese descreve a síntese e caracterização de complexos N-Salicilideno anilina(níquel) [Salan(Ni)] e N-Salicilideno anilina(platina) [Salan(Pt)]. A estrutura proposta desses compostos foi estabelecida por análise elementar (CHN), FTIR, TG, RMN de 1H e 13C. As atividades citotóxicas dos compostos sintetizados [Salan, NiCl2 e Salan(Ni)] foram avaliadas por ensaio MTT e os dados obtidos indicaram que Salan(Ni) demonstrou atividade citotóxica significativa contra linhagens celulares de leucemia e câncer de fígado. Além disso, neste estudo os efeitos histopatológicos e moleculares dos compostos sintetizados [Salan, Salan(Ni) e Salan(Pt)] foram caracterizados e comparados com o tratamento com BCG em um modelo animal de CBNMI. Os resultados obtidos indicaram que o grupo Salan(Ni): apresentou melhor recuperação histopatológica quando comparado ao grupo Câncer; aumentou os níveis da proteína UPIII; aumentou a expressão dos genes supressores de tumor PTEN e p53; causou inibição da angiogênese devido aos níveis proteicos elevados de endostatina e níveis mais baixos da proteína VEGF. No entanto, durante a instilação dos tratamentos, observou-se a precipitação dos compostos. Então, testes utilizando 2% de DMSO em óleo de milho como veículo para complexos do tipo Salan [Salan(Ni) e Salan(Pt)] foram realizados. Adicionalmente, o complexo Salan(Pt) foi incorporado a um carreador lipídico nanoestruturado (CLN) derivado de murumuru. O CLN carregado com Salan(Pt) [Salan(Pt)-CLN] foi preparado através do sistema de agitação mecânica e apresentou diâmetro médio de 165,4 nm e potencial zeta -34,4 mV. Por fim, os compostos obtidos [Salan(Ni), Salan(Pt), CLN livre, Salan(Pt)-CLN] foram administrados in vivo para avaliar seus efeitos contra CBNMI. A análise histológica revelou que o grupo Salan(Ni) apresentou melhor recuperação histopatológica. Análises de Western blotting (WB) indicaram que os tratamentos com Salan(Ni), Salan(Pt) e Salan(Pt)-CLN provavelmente ativam a via p53 diminuindo os níveis proteicos de Akt e PI3K. Em conclusão, os resultados indicaram que o complexo Salan(Ni) apresentou melhores efeitos na redução da agressividade do CBNMI comparado aos demais complexos e BCG. / Bladder cancer (BC) is the second most common genitourinary malignancy. Most (75%) BCs are non–muscle invasive (NMIBC) at first diagnosis [Ta, T1, and carcinoma in situ (CIS)]. Currently, the most used treatment against NMIBC involves the immunotherapy with BCG (Bacillus Calmette-Guérin) associated with the transurethral resection. However, the use of BCG can cause severe side effects and it is associated with high recurrence rate after treatment. Therefore, several approaches have been investigated, including the development of new molecules and also the improvement of the therapy with drugs conventionally used to treat cancers by using drug delivery systems. Considering the use of new molecules, metal complexes derived from Schiff bases (SBs) are versatile molecules with anticancer activity, providing new perspectives for the therapy of NMIBC. Regarding the drug delivery, over the past few years, nanostructured lipid carriers (NLCs) have been attracting considerable interest as alternative carriers for anticancer pharmaceuticals. Thus, in order to acquire more information about the chemistry of the complexes derived from the SB of N-Salicylidene aniline (Salan), as well as its effects on the progression of NIMBC, the present thesis describes the synthesis and characterization of N-Salicylidene aniline(nickel) [Salan(Ni)] and N-Salicylidene aniline(platinum) [Salan(Pt)] complexes. The proposed structure of these compounds was established by elemental analysis (CHN), FTIR, TG, 1H and 13C NMR. Cytotoxic activities of the synthesized compounds [Salan, NiCl2 and Salan(Ni)] were evaluated by the MTT assay and the obtained data indicated that Salan(Ni) showed significant cytotoxic activity against leukemia and liver cancer cells lines. Furthermore, in this study the histopathological and molecular effects of the synthesized compounds [Salan, Salan(Ni) and Salan(Pt)] were characterized and compared with BCG treatment in an animal model of NMIBC. Our results demonstrated that the Salan(Ni) group: improved histopathological recovery when compared with Cancer group; increased UPIII protein levels; increased expression of tumor suppressors genes PTEN and p53; inhibited of angiogenesis assigned to elevated levels of endostatin and lower levels of VEGF. However, during the instillation of treatments, compounds precipitation were observed. Then, tests using 2% DMSO in corn oil as vehicle for Salan-type complexes [Salan(Ni) and Salan(Pt)] were performed. Additionally, Salan(Pt) complex was incorporated into nanostructured lipid carrier (NLC) derived from murumuru. The NLC loaded with Salan(Pt) [Salan(Pt)-NLC] was prepared by using mechanical agitation method and had an average diameter of 165,4 nm as well as zeta potential of -34,4 mV. Ultimately, the obtained compounds [Salan(Ni), Salan(Pt), free NLC, Salan(Pt)-NLC] were administered in vivo to evaluete their effects against NMIBC. The histological analysis revealed that Salan(Ni) group Abstract MATSUMOTO, M. Y. Tese de Doutorado em Biologia Geral e Aplicada – UNESP – Botucatu showed bestter histopathological recovery. Western blotting (WB) analysis indicated that Salan(Ni), Salan(Pt) and Salan(Pt)-NLC treatments probably activate the p53 pathway by decreasing the protein levels of Akt and PI3K. In conclusion, the results showed the Salan(Ni) has better effects in reduction of NMIBC aggressiveness compared to the other complexes and BCG / 2013/04708-8
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Efeitos dos complexos de níquel e platina derivados de base de Schiff no câncer de bexiga urinária não-músculo invasivo

Matsumoto, Mirian Yoshiko January 2017 (has links)
Orientador: Wagner José Fávaro / Resumo: O câncer de bexiga (CB) é a segunda malignidade geniturinária mais comum. A maioria (75%) dos CBs são primeiramente diagnosticados como não-músculo invasivos (CBNMIs) nos estádios Ta, T1, e carcinoma in situ (CIS). Atualmente, o tratamento mais utilizado contra CBNMIs envolve a imunoterapia com Bacillus Calmette-Guérin (BCG) associada à ressecção transuretral (RTU). No entanto, a utilização de BCG pode causar graves efeitos colaterais e está associada com uma elevada taxa de recorrência após o tratamento. Por conseguinte, várias abordagens têm sido investigadas, incluindo o desenvolvimento de novas moléculas, assim como a melhoria da terapia com medicamentos convencionalmente utilizados no tratamento de tumores e a incorporação de sistemas de carreamento de fármacos. Considerando o uso de novas moléculas, complexos metálicos derivados de bases de Schiff (BSs) são compostos versáteis que apresentam atividade antitumoral, fornecendo assim novas perspectivas para a terapia do CBNMI. Em relação ao carreamento de fármacos, ao longo dos últimos anos, carreadores lipídicos nanoestruturados (CLNs) têm atraído considerável interesse como veículos alternativos para produtos farmacêuticos antitumorais. Assim, com o intuito de adquirir maior conhecimento a respeito da química dos complexos derivados da BS N-Salicilideno anilina (Salan) e também seus efeitos na progressão do CBNMI, esta tese descreve a síntese e caracterização de complexos N-Salicilideno anilina(níquel) [Salan(Ni)] e N-Sa... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bladder cancer (BC) is the second most common genitourinary malignancy. Most (75%) BCs are non–muscle invasive (NMIBC) at first diagnosis [Ta, T1, and carcinoma in situ (CIS)]. Currently, the most used treatment against NMIBC involves the immunotherapy with BCG (Bacillus Calmette-Guérin) associated with the transurethral resection. However, the use of BCG can cause severe side effects and it is associated with high recurrence rate after treatment. Therefore, several approaches have been investigated, including the development of new molecules and also the improvement of the therapy with drugs conventionally used to treat cancers by using drug delivery systems. Considering the use of new molecules, metal complexes derived from Schiff bases (SBs) are versatile molecules with anticancer activity, providing new perspectives for the therapy of NMIBC. Regarding the drug delivery, over the past few years, nanostructured lipid carriers (NLCs) have been attracting considerable interest as alternative carriers for anticancer pharmaceuticals. Thus, in order to acquire more information about the chemistry of the complexes derived from the SB of N-Salicylidene aniline (Salan), as well as its effects on the progression of NIMBC, the present thesis describes the synthesis and characterization of N-Salicylidene aniline(nickel) [Salan(Ni)] and N-Salicylidene aniline(platinum) [Salan(Pt)] complexes. The proposed structure of these compounds was established by elemental analysis (CHN), FTIR, TG... (Complete abstract click electronic access below) / Doutor
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SÃntese de NanopartÃculas da Galactomanana da Fava Danta (Dimorphandra gardneriana) Modificada / Synthesis oh Nanoparticles of Galactomannan of Fava Danta (Dimorphandra gardneriana)Modified

Ãrico de Moura Neto 15 May 2013 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Este trabalho teve como objetivo a preparaÃÃo de nanopartÃculas de derivados da galactomanana. O polissacarÃdeo (galactomanana) foi extraÃdo de sementes da Dimorphandra gardneriana com rendimento de 29Â3% e razÃo manose/ galactose (M:G) de 1,93Â0,02. A galactomanana foi modificada por reaÃÃo de sulfataÃÃo (FDS), oxidaÃÃo (FDO) e por acilaÃÃo com anidrido acÃtico (FDAc) e com anidrido propiÃnico (FDPr). Os derivados foram utilizados no desenvolvimento de nanopartÃculas por interaÃÃo com a quitosana via complexaÃÃo polieletrolÃtica, por formaÃÃo de base de Schiff, e por auto-organizaÃÃo. Os derivados da galactomanana foram caracterizados por espectroscopia na regiÃo do infravermelho (IV), por ressonÃncia magnÃtica nuclear, por anÃlise elementar, por cromatografia de permeaÃÃo em gel e por viscosidade intrÃnseca. O grau de substituiÃÃo para reaÃÃo de sulfataÃÃo foram 0,32 e 0,42. A razÃo de unidades glicosÃdicas/unidades oxidadas para os derivados oxidados foram 10:2; 10:4 e 10:8. Os derivados hidrofÃbicos foram confirmados pelo aparecimento de uma nova absorÃÃo em 1740 cm-1 no IV, atribuÃda ao estiramento C=O e a insolubilidade em Ãgua. NanopartÃculas com perfil unimodal foram obtidas nas trÃs rotas estudadas. As partÃculas de quitosana e galactomanana sulfatada foram obtidas por complexaÃÃo polieletrolÃtica com diÃmetros variando de 10Â6 a 377Â29 nm, Ãndice de polidispersividade de 0,11Â0,02 a 0,5Â0,1 e potencial zeta de â28Â2 a 59Â4 mV. Para as de quitosana e galactomanana oxidada obtidas via base de Schiff com diÃmetros variando de 8Â2 a 20Â9 nm, Ãndice de polidispersividade de 0,36Â0,04 a 0,57Â0,08 e potencial zeta de 0,4Â0,5 a 14Â1 mV. PartÃculas de galactomanana modificadas hidrofobicamente foram obtidas via auto-organizaÃÃo com diÃmetros variando de 35,3Â0,6 a 213Â28 nm, Ãndice de polidispersividade de 0,093Â0,003 a 0,9Â0,1 e potencial zeta de â26,3Â0,9 a â3Â2 mV. O diÃmetro, potencial zeta e Ãndice de poidispersividade sÃo influenciados pela metodologia e derivado utilizado, mas para todos os derivados da galactomanana obteve-se, em pelo menos uma condiÃÃo, nanopartÃculas compatÃveis para um potencial uso como carreadores de fÃrmacos. Fatores como: grau de modificaÃÃo, razÃo, ordem de adiÃÃo e concentraÃÃo dos polissacarÃdeos, pH e a adiÃÃo de fÃrmaco influenciaram no tamanho, Ãndice de polidispersividade, potencial zeta e estabilidade em soluÃÃo das partÃculas. / This work aimed the preparation of nanoparticles galactomannan derivatives. The polysaccharide (galactomannan) was from seeds of Dimorphandra gardneriana with yield of 29Â3% and mannose/galactose ratio (M:G) of 1.93Â0.02. The galactomannan was modified by sulfation raction (FDS), oxidation (FDO) and by acylation with acetic anhydride (FDAc) and proponic (FDPr) and derivates were used in the developmentof nanoparticles by interaction with chitosan by polyelectrolyte complexes, Schiff base formation and by self-assembled. Galactomannan derivatives were characterized by infrared spectroscopy (IR), nuclear magnetic resonance, elemental analysis, gel permeation chromatography and intrinsic viscosity. The degree of substitution for sulfataion reaction were 0.32 and 0.42; the ratio of glycosidic/oxidized units in oxidized derivatives was 10:2; 10:4 and 10:8. The hydrophobic derivatives were confirmed by the appearance of new absorption at 1740 cm-1 in IR, assigned to C=O stretching and water insolubility. Nanoparticles with unimodal profile were obtained on three routes studied. The particles of chitosan and sulfated galactomannan were obtained by complexation polyelectrolytic with diameters ranging from 10Â6 to 377Â29 nm, polydispersity index from 0.11Â0.02 to 0.5Â0.1 and zeta potential of â28Â2 to 59Â4 mV. For chitosan and oxidized galactomannan nanoparticles, obtained by Schiff base, diameters ranging from 8Â2 to 20Â9 nm, polydispersity index from 0.36Â0.04 to 0.57Â0.08 and zeta potential of 0.4Â0.5 to 14Â1 mV were obatined. Hydrophobically modified galactomannan particles were obtained by self-assembled with diameters ranging from 35.3Â0.6 to 213Â28 nm, polydispersity index from 0.093Â0.003 to 0.9Â0.1 and zeta potential of â26.3Â0.9 to â3Â2 mV. The diameter, zeta potential and polydispersity index are influenced by the methodology and derived used, but for all derivatives of galactomannan at least one condition shows nanoparticles compatible for potential use as drug carriers. Factors such as degree of modification, ratio, order of addition and concentration of polysaccharides, pH and addition of drug have influence on size, polydispersity index, zeta potential and solution stability of the particles.
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Estudo teórico conformacional da delta-toxina e teórico-experimental da interação de complexos de cobre-base de Schiff com o canal iônico da alfa-toxina de Staphylococcus aureus/

MELO, Maria Carolina de Araújo 12 July 2015 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-28T17:52:25Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Melo-MCA_dissertacao.pdf: 6271738 bytes, checksum: ce55245b114aac78286d16fa3cabf5d4 (MD5) / Made available in DSpace on 2016-06-28T17:52:25Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Melo-MCA_dissertacao.pdf: 6271738 bytes, checksum: ce55245b114aac78286d16fa3cabf5d4 (MD5) Previous issue date: 2015-07-12 / CAPES / O Staphylococcus (S.) aureus é responsável por inúmeros casos de infecções em animais e seres humanos. Essa bactéria secreta uma grande variedade de exoproteínas, incluindo quatro hemolisinas: alfa, beta, gama e delta. A atividade hemolítica da alfa-toxina (α-HL) se deve a formação de poros em membranas celulares. A α-HL é um monômero solúvel em água, que se torna mais estável ao se oligomerizar e formar poros heptaméricos transmembranares. Devido sua importância na patogênese bacteriana, essa proteína tem sido alvo de estudos no desenvolvimento de agentes terapêuticos. Sabe-se que os compostos de base de Schiff têm apresentado significativos resultados em testes de atividade biológica, incluindo antibacteriana. Neste contexto, avaliou-se a atividade de complexos de cobre-base de Schiff no bloqueio de poros da α-HL de S. aureus. Simultaneamente, foram realizados estudos conformacionais da δ-toxina em solução aquosa. Experimentos com eritrócitos de coelho expostos a α-HL foram utilizados na seleção dos compostos. Membranas lipídicas planas artificiais com canais individuais de α-HL, em condições de fixação de voltagem, foram utilizados para entender o mecanismo de ação dos compostos. Finalmente, avaliou-se através de docking molecular a interação entre os compostos e o canal de α-HL, visando corroborar o mecanismo de bloqueio. No estudo da δ-toxina, dinâmica molecular foi usada para determinar sua conformação em solução aquosa. Observou-se que os complexos de cobre inibiram parcialmente a atividade hemolítica da α-HL, devido ao bloqueio parcial dos canais desta toxina. O mecanismo molecular desse bloqueio ocorre pela interação dos compostos com a região de constrição do poro. Observou-se ainda que a δ-toxina em solução aquosa apresenta de 5 a 14 resíduos enovelados. Sugere-se que os complexos de cobre são potenciais candidatos a futuros agentes coadjuvantes no tratamento de infecções por S. aureus. / Staphylococcus (S.) aureus is responsible for a great number of infecctions in animals and humans. This bacteria produces several exoproteins and virulence factors, including four hemolysins: alfa, beta, gama and delta. The alfa-toxin (α-HL) hemolytic activity occurs due to the formation of pores in cellular membranes. α-HL is a soluble monomer in water, but becomes more stable when oligomerize and form transmembranar heptameric pores. Considering its importance for bacterial patogenesis, this protein has been target of studies on new antimicrobial agents. For example, base Schiff copper compounds have been observed to show significative results in biological activity assays, including antibacterial. In this context, the present work intended to evaluate the activity of a base Schiff-copper compounds to block the S. aureus α-HL ion channel. The most effective compounds were selected based on the exposition of rabbit erythrocytes to α-HL, and tested against control conditions. The mechanism of action of these compounds were evaluated through single channel experiments in planar lipid bilayrs, through eletrophisiological techniques. Finally, molecular docking studies were employed to confirm the blocking mechanism of such compounds. Moreover, molecular dynamics simulations were used to determine δ-toxin conformation in aqueous solutions. The obtained results indicated that the copper(II) compounds were capable of partially blocking the α-HL hemolytic activity, due to partial blockade of the ionic channels. The molecular mechanis of pore blockade was identified to mainly occur due to the interaction of the compounds to the pore constriction. Additionally, it was observed that δ-toxin in aqueous solution presents from 5 to 14 amino acids showing α-helical content. Based on these results, we suggest that such compound may be further evaluated as a coadjuvante agent for the treatment of staphylococcal infections
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Conception et réactivité de nouveaux complexes de lanthanides et de cobalt contenant des ligands rédox-actifs : application aux réductions multi-électroniques / Synthesis and reactivity of new complexes of lanthanides and cobalt bearing redox-active ligands for multi-electron reductions

Guidal, Valentin 27 October 2014 (has links)
La capacité des complexes de lanthanides divalents à promouvoir des réductions inhabituelles suscite actuellement un grand intérêt, tout particulièrement leur aptitude à activer des petites molécules telles CO2 et N2 dans des conditions douces. Les ions lanthanides, de par leurs propriétés de coordination tout à fait uniques pourraient offrir une alternative aux métaux de transition couramment utilisés pour la conception de catalyseurs. Cependant, comparativement aux métaux du bloc d, la chimie de coordination des lanthanides est exclusivement dominée par des transferts mono-électroniques qui impliquent uniquement les capacités rédox du centre lanthanide. C'est pourquoi le développement de nouveaux complexes de lanthanides capables de réaliser des réductions poly-électroniques est particulièrement intéressant. Dans un premier temps, nous avons utilisé des ligands rédox-actifs de type base de Schiff π-conjuguées pour étudier la chimie des ions lanthanides en réduction. Cela nous a permis d'isoler des complexes dans lesquels deux ou quatre électrons sont stockés sur le ligand via la formation de liaisons C-C. Ces mêmes liaisons sont rompues en présence d'agents oxydants et les électrons sont libérés pour réaliser des transformations multi-électroniques. Ce procédé a été observé pour des bases de Schiff tridentates et tétradentates, ce qui nous a permis de moduler les propriétés rédox des composés. La réactivité avec CO2 des complexes synthétisés a également été étudiée et nous avons identifié des complexes de néodyme capables de réduire le CO2. Dans un second temps, nous nous sommes intéressés à l'étude de complexes de cobalt contenant des ligands rédox-actifs de type base de Schiff π-conjuguées capables de stocker des électrons sous forme de liaisons C-C. Ce système, déjà étudié dans les années 1990, avait démontré sa capacité à activer le CO2. Avec l'intention de déterminer l'espèce active dans la réaction avec CO2, nous avons revisité ce système et mis en lumière un équilibre d'isomérie rédox entre un complexe de Co(I) et un complexe de Co(II) où un électron peut être localisé sur le métal ou sur le ligand. Nous nous sommes également intéressés aux paramètres qui régissent cet équilibre. En particulier, nous avons étudié l'influence de l'architecture du ligand sur les propriétés rédox des complexes de cobalt. Ces études offrent de nouvelles perspectives pour le développement de complexes capables d'effectuer la réduction électrocatalytique du CO2. / The redox chemistry of lanthanide complexes is attracting increasing interest because of the potential of divalent lanthanide complexes to promote unusual redox chemistry. For example they are able to activate small molecules such as CO2 and N2 in mild conditions. Due to the unique coordination and bonding properties of the lanthanide ions, their compounds could provide an attractive alternative to transition metals for the catalytic transformation of small molecules. However, metal-based multi-electron processes remain uncommon in lanthanide chemistry especially in comparison with the d-block metals; the chemistry of low-valent lanthanides being dominated by single-electron transfers. In this context, the first aim of this project was to investigate the association of lanthanides with a redox-active ligand acting as an independent electron reservoir within the same molecule. Accordingly, we examined the use of highly π-delocalized Schiff base ligands to study the reductive chemistry of lanthanide ions. This led to the isolation of electron-rich complexes which are stabilized by storing two or four electrons on the ligands through the formation of C-C bonds. Interestingly, these C-C bonds can be cleaved by oxidizing agents and the electrons released can participate in multi-electron redox reactions. This process was observed within different tridentate and tetradentate Schiff-base ligand scaffolds, allowing a tuning of the properties of the compounds. The ability of these complexes to react with CO2 has been studied, which lead to the identification of some neodymium complexes capable of reducing CO2. The second part of this work was dedicated to the study of cobalt complexes bearing redox-active and highly π-delocalized Schiff base ligands able to store electrons through the formation of C-C bonds. Seminal studies on Schiff base complexes of cobalt had been carried out in the 1990's and they demonstrated the ability of these complexes to activate CO2. With the aim to identify the active species responsible for CO2 activation, we have revisited these systems and highlighted a redox-isomeric equilibrium between a Co(I) and a Co(II) complexes where the electron can be localized on the cobalt or on the ligand. We also investigated the parameters influencing this equilibrium. In particular we have investigated the effect of the ligand architecture on the redox reactivity of cobalt complexes. Such studies pave the way to the development of new complexes for the electrocatlytic reduction of CO2.

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