A 1D coordination polymer built on asymmetric µ1,1,3-azide bridge: from unusual topology to magnetic properties and Cu(II)/Cu(I) redox reversibility

International audienceAn azide-bridged Cu(II) one dimensional polymer was synthesized in a one pot reaction in the presence of ammonia. The refined crystal structure evidenced the unusual asymmetric μ1,1,3 coordination mode of the azide ion leading to a {Cu(μ1,1,3-N3)(μ1-N3)(NH3)0.8(H2O)1.2}n chain. The redox process of this complex was studied by cyclic voltammetry evidencing the Cu(II)/Cu(I) reversibility. Magnetic measurements were interpreted as a uniform antiferromagnetic chain (J = −15.2 cm−1) holding rather strong inter-chain exchange (zJ′ = −2.8 cm−1). Multireference difference dedicated configuration interaction (DDCI) calculations confirmed the non-negligible intensity of inter-chain interactions and evidenced a strong influence of the type of coordinated solvent, NH3 or H2O, on the nature and magnitude of the magnetic exchange

Osmium-Nitrosyl Oxalato-Bridged Lanthanide-Centered Pentanuclear Complexes - Synthesis, Crystal Structures and Magnetic Properties

International audienceA series of pentanuclear heterometallic coordination compounds of the general formula (Bu 4 N) 5 [Ln{Os(NO)(μ-ox)-Cl 3 } 4 (H 2 O) n ] [Ln = Y (for 2) and Dy (for 3) when n = 0; Ln = Dy (for 3), Tb (for 4), and Gd (for 5) when n = 1] were synthesized by the reaction of the precursor (Bu 4 N) 2 [Os(NO)(ox)-Cl 3 ] (1) with the respective lanthanide(III) (Gd, Tb, Dy) or yttrium(III) chloride. For the five new complexes, the coordination numbers eight or nine are found for the central metal ion. The compounds were fully characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis, magnetic susceptibility measurements, and ESI mass spectrometry. In addition, compound 1 was studied by UV/Vis spectroscopy and cyclic voltammetry. The X-ray dif-fraction analyses revealed that the anionic complexes consist of a lanthanide or yttrium core bridged through oxalato li-gands to four octahedral osmium-nitrosyl moieties. This picture , in which the central ion is eight-coordinate, holds fo

SANÇÕES ADMINISTRATIVAS APLICADAS NA AVIAÇÃO: UMA ANÁLISE DOS PRINCÍPIOS APLICÁVEIS AOS PROCESSOS ADMINISTRATIVOS NA AVIAÇÃO

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Jurídicas. Direito.O presente trabalho busca averiguar se o processo administrativo sancionatório na aviação cumpre os princípios da lei dos processos administrativos (lei 9.784/99). O estudo se faz relevante pois é um campo ainda pouco estudado e precisa ser tratado com seriedade já que é uma das formas de demonstração do ius puniendi estatal. O objetivo do trabalho é verificar se os processos administrativos que resultam em multas para os operadores de aeronaves cumprem os princípios constitucionais e legais. Sendo assim, será desenvolvido um estudo sobre os aspectos que envolvem as sanções administrativas. Além disso, será trabalhado sobre os limites da presunção de veracidade da Administração Pública, bem como será investigada a relação entre os princípios da lei dos processos administrativos (lei 9.784/99) com os processos administrativos em estudo. Ao final, será apresentada uma análise de dois processos administrativos relacionados ao tema em discussão. Nessa análise é possível identificar algumas falhas da Administração Pública, tanto na concepção do processo administrativo em questão (normas aplicadas através de Portarias) quanto no desenvolvimento com relação aos princípios que deveriam ser observados. Percebe-se, por fim, a necessidade de aperfeiçoar o processo administrativo no seio da Junta de Julgamento de Aeronáutica, órgão responsável por todo o desenvolvimento desse processo. Essa pesquisa serve para apontar apenas alguns dos aspectos mais relevantes que necessitam uma posterior atenção e um número maior de estudos na área para que haja uma evolução nesse ramo do Direito

Heteropentanuclear Oxalato-Bridged nd-4f (n=4, 5) Metal Complexes with NO Ligand: Synthesis, Crystal Structures, Aqueous Stability and Antiproliferative Activity

A series of heteropentanuclear oxalate-bridged Ru(NO)-Ln (4d-4f) metal complexes of the general formula (nBu(4)N)(5)[Ln{RuCl3(-ox)(NO)}(4)], where Ln=Y (2), Gd (3), Tb (4), Dy (5) and ox=oxalate anion, were obtained by treatment of (nBu(4)N)(2)[RuCl3(ox)(NO)] (1) with the respective lanthanide salt in 4:1 molar ratio. The compounds were characterized by elemental analysis, IR spectroscopy, electrospray ionization (ESI) mass spectrometry, while 1, 2, and 5 were in addition analyzed by X-ray crystallography, 1 by Ru K-edge XAS and 1 and 2 by (CNMR)-C-13 spectroscopy. X-ray diffraction showed that in 2 and 5 four complex anions [RuCl3(ox)(NO)](2-) are coordinated to Y-III and Dy-III, respectively, with formation of [Ln{RuCl3(-ox)(NO)}(4)](5-) (Ln=Y, Dy). While Y-III is eight-coordinate in 2, Dy-III is nine-coordinate in 5, with an additional coordination of an EtOH molecule. The negative charge is counterbalanced by five nBu(4)N(+) ions present in the crystal structure. The stability of complexes 2 and 5 in aqueous medium was monitored by UV/Vis spectroscopy. The antiproliferative activity of ruthenium-lanthanide complexes 2-5 were assayed in two human cancer cell lines (HeLa and A549) and in a noncancerous cell line (MRC-5) and compared with those obtained for the previously reported Os(NO)-Ln (5d-4f) analogues (nBu(4)N)(5)[Ln{OsCl3(ox)(NO)}(4)] (Ln=Y (6), Gd (7), Tb (8), Dy (9)). Complexes 2-5 were found to be slightly more active than 1 in inhibiting the proliferation of HeLa and A549 cells, and significantly more cytotoxic than 5d-4f metal complexes 6-9 in terms of IC50 values. The highest antiproliferative activity with IC50 values of 20.0 and 22.4M was found for 4 in HeLa and A549 cell lines, respectively. These cytotoxicity results are in accord with the presented ICP-MS data, indicating five- to eightfold greater accumulation of ruthenium versus osmium in human A549 cancer cells

Porphyrin-based metal organic frameworks for electrocatalysis

International audienceBio-inspired catalysts can provide a clean and sustainable alternative to traditional stoichiometric processes. Porphyrins are widely used by nature in active sites of enzymes for electron and energy transfer reactions and as oxygen transporters. Furthermore, they are chemically and thermally robust extended molecules thus affording great potential as building blocks for porous coordination polymers. Building such hybrid materials is therefore an elegant path to access controlled porosity with a very high concentration of active sites.The structural diversity of metal organic frameworks combined with their high specific surface area has made them convincing candidates for catalytic applications. In our research we aim to develop porphyrin-based MOFs suitable for energy-related applications. An important focus is materials with improved stability and the possibility to control and tune the real nature of active site. This allows a deep structure/property study and rationalization. Thus we developed porphyrinic MOF systems with improved stability, as well as tuneable accessible active sites. Synthesis and characterizations of these materials will be presented. These redox-active materials have been used to modify electrodes and their activity was assessed for oxygen reduction catalysis: a key reaction in fuel cells technology. Electrocatalytic performances and mechanistic studies for oxygen reduction process will be discussed

Hemicryptophane-assisted electron transfer: a structural and electronic study

International audienceThree copper(II)@hemicryptophane complexes with various cavity sizes and shapes, Cu(II)@1, Cu(II)@2 and Cu(II)@3, were synthesized and characterized by near-IR/vis and EPR spectroscopies. The spectroscopic data are consistent with the presence of a trigonal-bipyramidal geometry of the N4Cu·H2O core, in accord with the energy-minimized structures obtained from DFT calculations. Cyclic voltammetry studies in CH2Cl2 showed irreversible redox processes, whereas electrolysis coulometry indicated that Cu(II)/Cu(I) complexes could be interconverted. Electrochemistry data of the complexes stress the crucial role of the cage structure of the hemicryptophane in the thermodynamics of the electron transfer.Graphical abstract: Hemicryptophane-assisted electron transfer: a structural and electronic stud

Ruthenium-Nitrosyl Complexes with Glycine, L-Alanine, L-Valine, L-Proline, D-Proline, L-Serine, L-Threonine and L-Tyrosine: Synthesis, X-ray Diffraction Structures, Spectroscopic and Electrochemical Properties and Antiproliferative Activity

The reactions of [Ru(NO)Cl5]2− with glycine (Gly), L- 16 alanine (L-Ala), L-valine (L-Val), L-proline (L-Pro), D-proline (D-Pro), 17 L-serine (L-Ser), L-threonine (L-Thr), and L-tyrosine (L-Tyr) in n- 18 butanol or n-propanol afforded eight novel complexes (1−8) of the 19 general formula [RuCl3(AA−H)(NO)]−, where AA = Gly, L-Ala, L- 20 Val, L-Pro, D-Pro, L-Ser, L-Thr, and L-Tyr, respectively. The 21 compounds were characterized by elemental analysis, electrospray 22 ionization mass spectrometry (ESI-MS), 1H NMR, UV−visible and 23 ATR IR spectroscopy, cyclic voltammetry, and X-ray crystallography. 24 X-ray crystallography studies have revealed that in all cases the same 25 isomer type (from three theoretically possible) was isolated, namely 26 mer(Cl),trans(NO,O)-[RuCl3(AA−H)(NO)], as was also recently 27 reported for osmium analogues with Gly, L-Pro, and D-Pro (see Z. Anorg. Allg. Chem. 2013, 639, 1590−1597). Compounds 1, 4, 28 5, and 8 were investigated by ESI-MS with regard to their stability in aqueous solution and reactivity toward sodium ascorbate. In 29 addition, cell culture experiments in three human cancer cell lines, namely, A549 (nonsmall cell lung carcinoma), CH1 (ovarian 30 carcinoma), and SW480 (colon carcinoma), were performed, and the results are discussed in conjunction with the lipophilicity of 31 compounds

Structural stability of DHMAI antibacterial dental composite following in vitro biological aging

International audienceObjective :To assess the impact of the quaternary ammonium antibacterial agent, Dimethyl-Hexadecyl-Methacryloxyethyl-Ammonium Iodide (DHMAI), on structural stability of an experimental resin composite after biological aging.Methods :Experimental resin composites containing 7.5% of DHMAI were incubated in a biological medium in the presence of a Streptococcus Mutans (SM) strain during 3 months. The physicochemical, mechanical, and thermal properties, before and after 3 months of aging, were evaluated using: Degree of Conversion (DC), Residual Functions (RF), Vitreous Transition (Tg), Thermal Expansion Coefficient (CTE) and thermal degradation using Fourier Transform Infrared Spectroscopy Analysis (FTIRATR), Differential Scanning Calorimetry (DSC), Thermo Mechanical analyses (TMA) and Thermo Gravimetric Analysis (TG).Results :Incorporation of DHAMI increased DC and decreased RF. After aging, DHMAI decreased and slowed RF release. Incorporation of 7.5% DHAMI provided significant modification of the thermal behavior (Tg and thermal degradation) but did not affect CTE. After aging, DHMAI enhanced the structural stability and improved resistance against biodegradation compared to the control composite.Significance :The development of an antibacterial dental composite based on DHMAI improved its physical, mechanical, and thermal behaviors, possibly enhancing dental composite longevity. Results suggest that DHMAI could be used in the composition of other bioactive dental materials