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1	Oxidation of nitrogen monoxide by oxoiron(IV) complexes: mechanistic studies and related investigations with an iron nitrosyl complex Owen, Travis Michael 01 December 2012 (has links) Reactions of the free radical nitrogen monoxide (NO) with metal–oxygen species of metalloproteins are relevant to NO metabolism and detoxification. For example, oxyhemoglobin and oxymyoglobin react with NO to form nitrate. The ferryl state of these globins also reacts with NO to reduce them to the FeIII state, forming nitrite. This has led to the suggestion that the role of NO could be that of an antioxidant of oxoiron(IV) and oxoiron(IV) protein radicals to inhibit oxidative damage. In turn, the ferrylglobin-mediated oxidation of NO to nitrite may play a role in NO scavenging and detoxification. In the case of peroxidase enzymes, NO has been shown to increase the activity of some enzymes by accelerating reduction of compound II to the FeIII state. While synthetic examples do exist for the chemistry of superoxometal complexes and NO, knowledge of the fundamental reactivity between oxometal complexes and NO is limited. To gain insight into the reactivity of synthetic oxoiron(IV) complexes toward NO, the reaction of [FeIVO(tmc)(OAc)]+ with NO, where the Fe center is coordinated by the macrocyclic nitrogen-donor ligand 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (tmc), has been investigated. This reaction caused reduction of the FeIV center to FeII and produced nitrite, which was identified in the form of [FeII(tmc)(ONO)]+. Mechanistic studies have been conducted to distinguish between two possible pathways involving either oxygen atom or oxide(·–) ion transfer from the FeIVO group to NO. As a result of studying the reactivity of a different oxoiron(IV) complex, [FeIVO(N4Py)]2+, toward NO, the formation of FeII and nitrate was observed. Mechanistic studies have revealed a 2:1 stoichiometry between FeIV and NO. From these results, a mechanism can be proposed that includes an initial oxide(·#8211;) ion transfer from FeIVO group to NO to form nitrite, followed by an oxygen atom transfer from a second equivalent of [FeIVO(N4Py)]2+ to the nitrite intermediate to form nitrate. This second step chemistry was confirmed by independently studying the reaction of [FeIVO(N4Py)]2+ with nitrite to form nitrate. There is also a biological inorganic chemistry in which metal nitrosyl species are oxidized to form innocuous nitrite or nitrate. In this context, the oxidation of the synthetic nitrosyl complex [Fe(tmc)(NO)]2+ has been studied, which also produced [FeII(tmc)(ONO)]+. The molecular structure of [FeII(tmc)(ONO)]+ determined by X-ray crystallography indicates a bidentate binding mode of the nitrito ligand via both oxygen atoms. The oxidation results are consistent with a net oxide(·–) ion transfer mechanism forming [FeII(tmc)(NO2)]+, followed by a subsequent linkage isomerization. For comparison purposes, several related, independently synthesized [FeII(tmc)X]+ complexes (X = NO2–, NO3–, AcO–) have been characterized by spectroscopic techniques, X-ray crystallography and differential pulse and cyclic voltammetry. A final investigation involved studying the reactivity of a series of [FeIVO(tmc)X]+ (X = CF3SO3–, CF3CO2–, AcO–) complexes toward organic substrates by oxygen atom transfer and hydrogen atom abstraction to construct a reactivity trend depending on the strength of the axial ligand X. Iron Mechanism Nitrogen Monoxide Nitrosyl Oxoiron Chemistry
2	高クヌッセン数流れ中の表面圧力計測に適した感圧塗料の開発森, 英男, MORI, Hideo, 新美, 智秀, NIIMI, Tomohide, 大島, 佑介, OSHIMA, Yusuke, 平光, 円, HIRAKO, Madoka 11 1900 (has links) No description available. Pressure Distribution Rarefield Gas Optical Measurement Pressure Sensitive Paint Two-dimensional Measurement Nitrogen Monoxide
3	Καταλύτες μείωσης εκπεμπόμενων οξειδίων του αζώτου ( βελτίωση υπαρχόντων καταλυτών και ανάπτυξη νέων για τη μείωση του ποσού των οξειδίων του αζώτου που ως ρύποι εκπέμπονται από στατικές πηγές ή οχήματα ) Μπίρμπας, Γεώργιος 21 October 2009 (has links) - / - Κατάλυση Μονοξείδιο του αζώτου Μόλυνση 541.395 Catalysis Catalytic reactions Nitrogen monoxide Pollution
4	Εκλεκτική καταλυτική αναγωγή του μονοξειδίου του αζώτου (NO) προς άζωτο (N2) Φλιάτουρα, Αικατερίνη 21 October 2009 (has links) - / - Κατάλυση Χημική τεχνολογία Αμμωνία Μονοξείδιο του αζώτου 541.395 Catalysis Catalytic reactions Chemical technology Ammonia Nitrogen monoxide
5	Photoacoustic Calorimetry Studies of the Earliest Events in Horse Heart Cytochrome-c Folding Word, Tarah A. 16 September 2015 (has links) The protein folding problem involves understanding how the tertiary structure of a protein is related to its primary structure. Hence, understanding the thermodynamics associated with the rate-limiting steps for the formation of the earliest events in folding is most crucial to understanding how proteins adopt native secondary and tertiary structures. In order to elucidate the mechanism and pattern of protein folding, an extensively studied protein, Cytochrome-c (Cc), was chosen as a folding system to obtain detailed time-resolved thermodynamic profiles for the earliest events in the protein folding process. Cytochrome-c is an ideal system for understanding the folding process for several reasons. One being that the system can unfold and refold reversibly without the loss of the covalently attached heme group. A number of studies have shown that under denaturing conditions, ferrous Cc (Fe2+Cc) heme group in the presence of carbon monoxide (CO) results in a disruption of the axial heme Methionine-80 (Met80) bond ultimately unfolding the protein. CO-photolysis of this ferrous species results in the formation of a transient unfolded protein that is poised in a non-equilibrium state with the equilibrium state being that of the native folded Fe2+Cc complex. This allows for the refolding reaction of the protein to be photo-initiated and monitor on ns - ms timescales. While CO cannot bind to the ferric form, nitrogen monoxide (NO) photo-release has been developed to photo-trigger ferric Cc (Fe3+Cc) unfolding under denaturing conditions. Photo-dissociation of NO leaves the Fe3+complex in a conformational state that favors unfolding thus allowing the early unfolding events of Fe3+Cc to be probed. Overall the results presented here involve the use of the ligands CO and NO along with photoacoustic calorimetry (PAC) to photo-trigger the folding/unfolding reaction of Cc (and modified Cc). Thus, obtaining enthalpy and molar volume changes directly associated with the initial folding/unfolding events occurring in the reaction pathways of both Fe2+ and Fe3+Cc systems that are most essential to understanding the driving forces involved in forming the tertiary native conformation. The PAC data shows that folding of proteins results from a hierarchy of events that potentially includes the formation of secondary structures, hydrophobic collapse, and/or reorganization of the tertiary complex occurring over ~ns – tens of µs time ranges. In addition, the PAC kinetic fits presented in this work is the first to report Cc folding exhibiting heterogeneous kinetics (in some cases) by utilizing a stretched exponential decay function. Protein Folding Chloramine-T Cytochrome-c Ferric Cytochrome-c Ferrous Cytochrome-c Carbon Monoxide-bound Nitrogen Monoxide-bound Biophysics Chemistry
6	Estanatos de cálcio (casno3) dopados com Fe3+, Co2+ ou Cu2+ Aplicados na fotodegradação de Remazol Amarelo Ouro E na redução de NO com CO ou NH3 Santos, Guilherme Leocárdio Lucena dos 28 April 2017 (has links) Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-20T14:18:13Z No. of bitstreams: 1 arquivototal.pdf: 7366953 bytes, checksum: e2858ff3ade34aa9cdf821b90999c936 (MD5) / Made available in DSpace on 2017-06-20T14:18:13Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 7366953 bytes, checksum: e2858ff3ade34aa9cdf821b90999c936 (MD5) Previous issue date: 2017-04-28 / Calcium stannate, CaSnO3, is orthorhombic perovskite-type that presents technological applications as catalysts and photocatalysts. In this work, undoped CaSnO3 and doped with Fe3+, Co2+ or Cu2+ were obtained by the modified Pechini method and applied in photodegradation of the textile dye Remazol Golden Yellow and as catalysts in the reduction reaction of nitrogen monoxide (NO). Furthermore, these materials were deposited on the ZrO2 support or Pd2+-doped or Pd impregnated and evaluated in the reduction of NO with CO and NO with NH3. The catalysts were characterized by thermogravimetric analysis (TG/DTA), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), infrared spectroscopy (IR), Raman spectroscopy, analysis of the surface area by the BET method, scanning electron microscopy with field emission (FE-SEM) and transmission electron microscopy (TEM). XRD patterns showed a small change in the long range-order for the doped samples due to partial substitution of cations. The Raman spectra indicated that the incorporation of Fe3+, Co2+ and Cu2+ in the CaSnO3 lattice promoted a symmetry breaking, which was confirmed by the change of the band gap values of the samples. The photocatalytic tests of RNL dye were performed in the reactor using a UVC lamp (λ = 254 nm). The catalytic tests were carried out in a reactor containing a gaseous mixture with stoichiometric amounts of nitrogen monoxide (NO) and carbon monoxide (CO) in helium in the temperature range of 300 °C to 700 °C or in a reactor containing a mixture of NO and ammonia (NH3) in helium in the temperature range of 250 °C to 500 °C. The results of the photocatalytic evaluation showed that CaSnO3 doping with transition metals increased the photocatalytic efficiency of the material, especially for the Cu2+ (76% of discoloration), which was related to the while the decrease in the intensity of the photoluminescence spectrum as a function of doping. The catalytic tests of NO with CO showed that Co2+ and Cu2+-doped perovskites showed 100% of conversion, at temperatures above 500ºC. The palladium impregnation promoted the conversion of NO with CO throughout the evaluated temperature range, but it did not favor the reaction of NO with NH3, probably due to the oxidation of NH3 by Pd. The perovskite deposited on the ZrO2 support showed the best catalytic conversion values. The results of FEG and TEM confirmed the deposition of the active phase on the ZrO2 support and indicated the formation of core@shell systems. / Estanato de cálcio, CaSnO3, é uma perovskita do tipo ortorrômbica que apresenta aplicações tecnológicas como catalisadores e fotocatalisadores. Neste trabalho, CaSnO3 não dopado e dopado com Fe3+, Co2+ ou Cu2+ foram obtidos pelo método Pechini-modificado e aplicados na fotodegradação do corante têxtil remazol amarelo ouro (RNL), e como catalisadores na reação de redução de monóxido de nitrogênio (NO). Além disso, esses materiais foram depositados sobre o suporte catalítico ZrO2 ou impregnados ou dopados com paládio e avaliados na redução de NO com CO e NO com NH3. Os catalisadores foram caracterizados por análise termogravimétrica (TG/DTA), difração de raios-X (DRX), espectroscopia de absorção na região do ultravioleta e do visível (UV-Vis), espectroscopia vibracional na região do infravermelho (IV), espectroscopia Raman, análise da área superficial (SBET), microscopia eletrônica de varredura com emissão de campo (MEV-EC) e microscopia eletrônica de transmissão (MET). Os resultados de DRX mostraram uma pequena mudança na ordem a longo alcance das amostras dopadas devido à substituição parcial dos cátions. Os espectros Raman indicaram que a incorporação dos metais Fe3+, Co2+ e Cu2+ na rede do CaSnO3 promoveu quebra de simetria, o que foi confirmado pela mudança nos valores do band gap das amostras. Os ensaios fotocatalíticos do corante RNL foram realizados em reator utilizando uma lâmpada UVC (λ= 254 nm). Por sua vez, os testes catalíticos foram realizados em um reator contendo uma mistura gasosa, com quantidades estequiométricas de monóxido de nitrogênio (NO) e monóxido de carbono (CO), em hélio, na faixa de temperatura de 300°C a 700°C ou em um reator contendo mistura de NO e amônia (NH3), em hélio, na faixa de temperatura de 250°C a 500°C. Os resultados da avaliação fotocatalítica mostraram que a dopagem do CaSnO3 com os metais de transição aumentou a eficiência fotocatalítica do material, sendo mais expressiva para o material dopado com Cu2+ (76% de descoloração), o que foi relacionado à diminuição na intensidade dos espectros de fotoluminescência em função da dopagem. Os testes catalíticos de NO com CO mostraram que as perovskitas mássicas dopadas com Co2+ e Cu2+ apresentaram 100% de conversão, em temperaturas superiores a 500ºC. A impregnação com paládio favoreceu a conversão de NO com CO em toda a faixa de temperatura avaliada, no entanto, desfavoreceu a reação de NO com NH3, provavelmente devido à oxidação de NH3 pelo Pd. As perovskitas depositadas sobre o suporte ZrO2 mostraram os melhores valores de conversão catalítica. Os resultados de MEV-EC e MET confirmaram a deposição da fase ativa sobre o suporte ZrO2 e indicaram a formação de sistemas core@shell. Perovskita Catalisadores Fotodegradação Suportes catalíticos Monóxido de nitrogênio Corantes têxteis Catalysts Photodegradation Catalyst supports Nitrogen monoxide Textile dyes Perovskite CIENCIAS EXATAS E DA TERRA::QUIMICA
7	Studies of urban air quality using electrochemical based sensor instruments Popoola, Olalekan Abdul Muiz January 2012 (has links) Poor air quality has been projected to be the world’s top cause of environmental premature mortality by 2050 surpassing poor sanitation and dirty water (IGBP / IGAC press release, 2012 ). One of the major challenges of air quality management is how to adequately quantify both the spatial and temporal variations of pollutants for the purpose of implementing necessary mitigation measures. The work described in this thesis aims to address this problem using novel electrochemical based air quality (AQ) sensors. These instruments are shown to provide cost effective, portable, reliable, indicative measurements for urban air quality assessment as well as for personal exposure studies. Three principal pollutants CO, NO and NO2 are simultaneously measured in each unit of the AQ instrument including temperature / RH measurements as well as GPS (for time and position) and GPRS for data transmission. Laboratory studies showed that the electrochemical sensor nodes can be highly sensitive, showing linear response during calibration tests at ppb level (0-160 ppb). The instrumental detection limits were found to be < 4 ppb (CO and NO) and < 1 ppb for NO2 with fast response time equivalent to t90 < 20 s. Several field studies were carried out involving deployment of both the mobile and static electrochemical sensor nodes. Results from some short-term studies in four different cities including Cambridge (UK), London (UK), Valencia (Spain) and Lagos (Nigeria) are presented. The measurements in these cities represent snapshot of the pollution levels, the stark contrast between the pollution level especially CO (mean mixing ratio of 16 ppm over 3 hrs) in Lagos and the other three cities is a reflection of the poor air quality in that part of the world. Results from long-term AQ monitoring using network of 46 static AQ sensors were used to characterise pollution in different environments ranging from urban to semi-urban and rural locations. By coupling meteorological information (wind measurements) with pollution data, pollution sources, and phenomena like the street canyon effect can be studied. Results from the long-term study also revealed that siting of the current fixed monitoring stations can fail to represent the actual air quality distribution and may therefore be unrepresentative. This work has shown the capability of electrochemical based AQ sensors in complementing the existing fixed site monitors thus demonstrating an emerging measurement paradigm for air quality monitoring and regulation, source attribution and human exposure studies. 540
8	Electron Transfer and Other Reactions Using Atomic Metal Anions Butson, Jeffery M. 04 February 2014 (has links) The atomic metal anions Rb-, Cs-, Cu-, Ag- and Fe- have been generated in the gas phase and reacted with various neutral reactants in a triple quadrupole mass spectrometer. The metal anions were formed via electrospray ionization of the metal-oxalate solutions and form in gas phase between the capillary and the first quadrupole. Neutral gas phase reactants investigated include NO, NO2, SO2, C6F5OH, C6F5NH2, C6F6, E-octafluoro-butene and 1,2,3/1,2,4/1,3,5 trifluoro-benzene. When possible, CBS-4M methods were used to suggest the lowest energy products based on relative energy. Observed reactions of atomic metal anions with the aforementioned neutral species include electron transfer and dissociative electron transfer to the neutral gas phase reactants. In addition, hydrogen abstraction and fluorine abstraction forming a neutral metal hydride or fluoride as well as the formation of multiply substituted metal-oxide/fluoride anions was also observed. Metal-complex anions observed from the gas phase reactions include CuF-,CuF2-,CuO-,CuO2-, FeO-, FeO2-, FeO3-, FeF-, FeF2-, FeF3-, CsF- and CsF2-. Metal Anion Metal Anion Atomic Atomic Metal Anion Atomic Metals Atomic Metal Anions Anions Metals Mass Spectrometer Triple Quadrupole Rb Cs Fe Cu Ag Cs- Rb- Fe- Cu- Ag- pentafluoroaniline pentafluorophenol nitrogen dioxide sulfur dioxide nitrogen oxide nitrogen monoxide oxygen oxalic oxalic acid gas phase electrospray ionization electrospray ionization electro-spray ionization electro-spray hexafluorobenzene 1,2,3-trifluorobenzene 1,2,4-trifluorobenzene 1,3,5-trifluorobenzene fluorine E-octafluoro-butene octafluoro-butene octafluoro butene CBS-4M abstraction hydrogen abstraction fluorine abstraction hydride fluoride metal hydride metal fluoride caesium fluoride rubidium fluoride iron fluride copper fluoride rubidium caesium iron copper silver iron anion copper anion rubidium anion caesium anion silver anion cesium cesium anion atomic caesium anion atomic cesium anion atomic rubidium anion atomic iron anion atomic copper anion atomic silver anion 1,2,3 trifluorobenzene 1,2,4 trifluorobenzene 1,3,5 trifluorobenzene copper fluoride anion iron fluoride anion copper difluoride copper difluoride anion iron difluoride iron difluoride anion iron trifluoride iron trifluoride anion cesium fluoride cesium fluoride anion caesium difluoride anion caesium difluoride cesium difluoride cesium difluoride anion caesium fluoride anion nitrogen monoxide anion sulfur dioxide anion nitrogen dioxide anion copper oxide copper oxide anion copper dioxide copper dioxide anion iron oxide iron oxide anion iron dioxide iron dioxide anion iron trioxide iron trioxide anion electron transfer
9	Electron Transfer and Other Reactions Using Atomic Metal Anions Butson, Jeffery M. January 2014 (has links) The atomic metal anions Rb-, Cs-, Cu-, Ag- and Fe- have been generated in the gas phase and reacted with various neutral reactants in a triple quadrupole mass spectrometer. The metal anions were formed via electrospray ionization of the metal-oxalate solutions and form in gas phase between the capillary and the first quadrupole. Neutral gas phase reactants investigated include NO, NO2, SO2, C6F5OH, C6F5NH2, C6F6, E-octafluoro-butene and 1,2,3/1,2,4/1,3,5 trifluoro-benzene. When possible, CBS-4M methods were used to suggest the lowest energy products based on relative energy. Observed reactions of atomic metal anions with the aforementioned neutral species include electron transfer and dissociative electron transfer to the neutral gas phase reactants. In addition, hydrogen abstraction and fluorine abstraction forming a neutral metal hydride or fluoride as well as the formation of multiply substituted metal-oxide/fluoride anions was also observed. Metal-complex anions observed from the gas phase reactions include CuF-,CuF2-,CuO-,CuO2-, FeO-, FeO2-, FeO3-, FeF-, FeF2-, FeF3-, CsF- and CsF2-. Metal Anion Metal Anion Atomic Atomic Metal Anion Atomic Metals Atomic Metal Anions Anions Metals Mass Spectrometer Triple Quadrupole Rb Cs Fe Cu Ag Cs- Rb- Fe- Cu- Ag- pentafluoroaniline pentafluorophenol nitrogen dioxide sulfur dioxide nitrogen oxide nitrogen monoxide oxygen oxalic oxalic acid gas phase electrospray ionization electrospray ionization electro-spray ionization electro-spray hexafluorobenzene 1,2,3-trifluorobenzene 1,2,4-trifluorobenzene 1,3,5-trifluorobenzene fluorine E-octafluoro-butene octafluoro-butene octafluoro butene CBS-4M abstraction hydrogen abstraction fluorine abstraction hydride fluoride metal hydride metal fluoride caesium fluoride rubidium fluoride iron fluride copper fluoride rubidium caesium iron copper silver iron anion copper anion rubidium anion caesium anion silver anion cesium cesium anion atomic caesium anion atomic cesium anion atomic rubidium anion atomic iron anion atomic copper anion atomic silver anion 1,2,3 trifluorobenzene 1,2,4 trifluorobenzene 1,3,5 trifluorobenzene copper fluoride anion iron fluoride anion copper difluoride copper difluoride anion iron difluoride iron difluoride anion iron trifluoride iron trifluoride anion cesium fluoride cesium fluoride anion caesium difluoride anion caesium difluoride cesium difluoride cesium difluoride anion caesium fluoride anion nitrogen monoxide anion sulfur dioxide anion nitrogen dioxide anion copper oxide copper oxide anion copper dioxide copper dioxide anion iron oxide iron oxide anion iron dioxide iron dioxide anion iron trioxide iron trioxide anion electron transfer

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