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Naturally occurring canine osteosarcoma in the dog animal model for research of targeted radiotherapy using beta-emitting radioisotopes with various ligandsMilner, Rowan James 18 June 2013 (has links)
Metastatic and primary bone cancers are devastating diseases of paediatric and adult humans because of the morbidity associated with bone pain. Controlling bone pain from multiple metastatic sites can be difficult in end-stage cancers using conventional therapies. Bone-seeking radiopharmaceuticals have been successful in this area as radiation can be delivered with moderate selectivity to the target. Unfortunately, targeted radiotherapy using radiopharmaceuticals have been relegated to palliative therapy as myelosuppression largely limits the radiation dose to sub-therapeutic levels. Efforts to overcome this therapeutic limitation include autologous bone marrow transplants in combination with chemotherapy-radiosensitization and the development of new radiopharmaceuticals. Development work using laboratory rodent models has been complicated by dosimetric limitations because of size and inherent problems with human xenografted tumour models in rodents. To address this need we studied naturally occurring canine osteosarcoma as a translational model for human bone cancer. Central to our hypothesis was that naturally occurring canine osteosarcoma would serve as an investigational model for comparing the pharmacokinetics (biodistribution), dosimetry, toxicity, and therapeutic effect of 153Sm-EDTMP, 188Re-HEDP, 186Re-HEDP, and a novel ligand, polyethyleneiminomethyl phosphonic acid (PEI-MP). Data collected from existing radiopharmaceuticals was then compared to PEI-MP labelled with 99mTc, 153Sm, and 186Re. This innovative and unique study allowed for the evaluation of various radiopharmaceuticals in a naturally occurring animal model of bone cancer, documenting the pharmacokinetics and dosimetry of a novel radiolabelled-ligand (PEI-MP). Benefits resulting from the successful completion of the study would allow more rapid transfer of rodent preclinical data into a naturally occurring cancer model more resembling to the human diseases and would thus more likely identify problems with pharmacokinetics and toxicity before proceeding to expensive clinical trials. The expected outcomes of the study were originally formulated based on limited previous published data in dogs. For instance, no data exists describing the pharmacokinetics or toxicity of 188Re-HEDP and 186Re-HEDP in the dog. The study was conducted in two phases. The first phase deals with the evaluation of 153Sm-EDTMP, 188Re-HEDP, and 186Re-HEDP in the dog model. Phase-two was the development of a novel ligand (PEI-MP) in the dog model of osteosarcoma, which has the characteristics of an ideal ligand. Pharmacokinetic results for 153Sm-EDTMP in normal dogs (n=4) for blood were similar to published reports for dogs and human. When compared statistically to human data the majority of results were the same, lending credence to the hypothesis that dogs could serve as models for human radiopharmaceutical research. Normal dogs and the osteosarcoma dog did differ from human pharmacokinetics in the urine elimination phase (t½-â). This can most likely be explained by the tumour burden in the human research populations or due to the fact that most humans were aged and likely to have some renal disease. Certainly, the trend in dogs with osteosarcoma was to have a prolonged urine elimination phase (t½-â) compared to normal dogs which supported the hypothesis that the biodistribution and pharmacokinetics results from dogs were similar to human published data. Statistical comparisons were also made between normal dogs receiving 188Re-HEDP and 153Sm-EDTMP. The prolonged urine elimination phase (t½-â) and increased blood retention of 188Re-HEDP was most likely a reflection of prolonged bone washout and soft issue retention. This could be attributed to the differences between the antiresorptive capability of bisphosphonate ligands e.g., EDTMP (lexidronam) with a greater than 100-fold antiresorptive capability than HEDP (etidronate). Additional observational biodistribution studies using macro- and micro-autoradiography techniques were also performed in canine tissue and Sprague-Dawley rats. Results from the studies showed heterogeneous uptake within tumours in dogs. In rats, localization of 153Sm-EDTMP in red marrow areas would lead to a high radiation dose to blood producing elements. In addition, high uptake was documented at the metaphyseal growth plate confirming the likelihood of a delay or cessation of growth if 153Sm-EDTMP were used in growing children. Phase-one of the clinical trial in dogs with naturally occurring osteosarcoma identified only mild toxicity at the dosage rate of 37 MBq/kg (1 mCi/kg) for both 153Sm-EDTMP and188Re-HEDP. In addition, a pilot trial was conducted in dogs receiving 153Sm-EDTMP which also received a carboplatin infusion at the time of the radiopharmaceutical administration followed by another 3 cycles of carboplatin at 3 weekly intervals. No differences in toxicity were noted between the carboplatin group and dogs receiving only 153Sm-EDTMP. As a part of the 188Re-HEDP clinical trial, 3 dogs with osteosarcomas received weekly dose of 188Re-HEDP at 37MBq/kg for 4 weeks in which only mild toxicity was noted. Unfortunately, there was no cessation in growth of the tumours, with all dogs showing progression. The median survival time for both radiopharmaceuticals was 4 months, significantly shorter than the 10-month median survival time for amputation and chemotherapy. Interestingly six dogs that had 99mTc-MDP and 153Sm-EDTMP showed scans of tumours that had consistently lower 99mTc-MDP uptake ratios (normal bone compared to cancerous bone) compared to solely 153Sm-EDTMP. In contrast, this was not evident for uptake ratios between 188Re-HEDP and 99mTc-MDP scans. Once again, this finding highlights the differences between the antiresorptive capabilities of the bisphosphonates ligands. Interestingly, another three dogs were scanned with 99mTc-MDP , 153Sm-EDTMP, and 99mTc-PEI-MP (10-30 kDa) showed a variation in uptake between scans of the same tumours. More importantly, the uptake ratios of 99mTc-MDP and 153Sm-EDTMP scans showed wide variation with a coefficient of variance of 52% and 39% respectively. However, the range in uptake from the 99mTc-PEI-MP (10-30 kDa) scan was narrow with a coefficient of variance of only 6%. This could be attributed to more consistent uptake ratio of the unique ligand PEI-MP and its hypothesized mechanism of action: enhanced permeability and retention (EPR) in tumour vasculature. This requires further investigation with larger groups. In phase-two, the pharmacokinetic result for the novel ligand PEI-MP was initially studied labelled with 99mTc. Various molecular weights were tested in normal dogs and compared to previously published results in baboons. Results from the dog studies were found to be similar to those from the primate study. As in the primate study, molecular weight and charge played a significant role in 99mTc-PEI-MP pharmacokinetics. Increasing the size of the macromolecules and altering their charge resulted in marked changes in their pharmacokinetics and biodistribution. The PEI-MP molecular weight of 10-30 kDa and 20-30 kDa were the most promising and fulfilled the hypothesized criteria of an ideal radiopharmaceutical. In keeping with the aims of the study, the 20-30kDa polymer was considered more desirable because of its faster clearance. However, because of the limitations imposed by the percentage yield of the different molecular weights of the ligand during filtration, we decided to label the 10-30kDa molecular weight MW-fraction with 153Sm. Unexpectedly, the 153Sm-PEI-MP 10-30 kDa had a prolonged urine elimination phase (t½-â) associated with increased liver uptake when compared to 99mTc-PEI-MP10-30 kDa. To explain this, computer modelling for blood plasma (ECCLES) was done which predicted that there would be some chemical dissociation of the 153Sm from the PEI-MP polymer in blood. This is due to interaction between the radiopharmaceutical and citrate, forming 153Sm-citrate. The ECCLES model for blood plasma also predicted that the anionic MW-fraction, PEI-MP 10-30kDa, would be a poor ligand complexed to 166Ho, 212Pb, 213Pb, and 89Sr, but was expected to be effective when complexed to 186Re or 188Re, based on their close proximity to 99mTc on the periodic table. As a preliminary study 186Re was complexed to 20-30 kDa (n=2) and 30-50 kDa (n=1) MW-fractions and tested in dogs. The results were similar to 99mTc-PEI-MP 10-30 kDa. The biodistribution data and pharmacokinetic data were also used to do comparative dosimetry between radiopharmaceuticals. Not surprisingly, the dosimetry data confirmed the high red marrow dose for 153Sm-EDTMP and the increased soft-tissue dose of the radionuclides complexed to HEDP. The radiation dose to the tumour for all radiopharmaceuticals fell within the range of 26Gy to 44Gy. This is well within the range used to treat canine osteosarcoma using external beam radiotherapy. When compared to external beam radiotherapy, the probable lack of tumour response in our clinical trial relates to the heterogenous distribution of the radiopharmaceutical in the tumour and the inherent resistance of osteosarcoma cells to continuous low-dose radiation delivery (CLDR) inherent in radionuclide -particle decay. The study met the majority of outcomes with the exception of labelling PEI-MP with 153Sm. This was due to the interaction of the 153Sm-PEI-MP complex with citrate ions in blood. Rapid deterioration of the Rhenium-188 generator also led to earlier than expected curtailment of the 188Re-HEDP therapeutic trial although sufficient data was available to be used in a comparative study. / Thesis (PhD)--University of Pretoria, 2013. / Internal Medicine / unrestricted
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Two-in-one Pincer Type Ligands and Their Metal Complexes for Catalysis / Two-in-one Pincer Type Ligands and Their Metal Complexes for CatalysisGers-Barlag, Alexander 24 November 2016 (has links)
No description available.
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Multivalent Carbohydrates : Synthesis And Studies Of Cluster Glycosides On Photoswitchable And Dendritic ScaffoldsSrinivas, Oruganti 07 1900 (has links) (PDF)
No description available.
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Chemistry Of Oxo And Carboxylato Bridged Diruthenium Complexes Having Imidazole Terminal LigandsSudha, C 10 1900 (has links) (PDF)
No description available.
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Design de composites verts pour la dépollution des terres agricoles : expérience et théorie / Design of green composite for the decontamination of agricultural land : experimental and theoreticalEl Adraa, Khaled 11 December 2014 (has links)
Des matériaux verts biodégradables à base de Montmorillonite et de cystéine ont été préparés dans le but de co-adsorber des cations de métaux lourds et des polluants émergeants en combinant l’expérience et la théorie (calculs DFT). Les analyses thermiques différentielles ont permis d’estimer le pourcentage d’eau et de matière organique, informations indispensables permettant de lancer les calculs théoriques. La première étape a consisté en l’adsorption des cations de métaux lourds tels que Pb2+, Cu2+, Co2+, Zn2+ et Hg2+ par le composite montmorillonite-cystéine et leurs caractérisations physico-chimiques. La deuxième étape a consisté à co-adsorber le sulfadiazine dans le composite montmorillonite-cystéine-cation de métal lourd. La spectroscopie de résonance magnétique du 13C nous a permis d’identifier les composites où une réaction de complexation s’est produite : En effet des décalages importants dans le déplacement chimique sont observés dans ce dernier cas. Parallèlement à cette partie expérimentale, la modélisation moléculaire nous a permis de calculer les énergies des différents complexes formés. Nous avons ainsi pu estimer le complexe le plus stable à partir des énergies obtenues. Un bon accord entre les résultats expérimentaux et théoriques a été obtenu. Des études de relargage à force ionique contrôlée ont été effectuées. Les résultats ont montré une bonne rétention des divers polluants en présence de cystéine. / Layered silicates like smectites are important soil components. Many works have been devoted to functionalize these materials in order to increase their chelating properties which may help retain heavy metals. It is well known that Cd2+, Hg2+, Pb2+, Co2+ and Zn2+ forms stable complexes with sulfur-containing organic ligands like cysteine. The first step of this work was the preparation of cysteine-montmorillonite composite through procedures that are well mastered. The second step was the study of the capacity of these composite materials to adsorb heavy metal cations. The chemical data demonstrates that the amount of cysteine detected on montmorillonite increases rapidly during the first few hours to attain a plateau after 24h. A comparison between the chelating properties of the resulting hybrid inorganic-organic materials and the pure montmorillonite was carried out for the following heavy metal cations Cd2+, Hg2+, Pb2+, Co2+ and Zn2+. It appears that the adsorption capacity of both materials is comparable. However, in release experiments, the heavy metal cations are more strongly retained by the hybrid material. Thermogravimetric analysis shows a special behavior with mercury and copper cations. Interactions between the hybrid clay mineral and the inorganic hosts were studied by spectroscopic methods such as solid-state NMR and FTIR. The experimental data were interpreted and supported by the use of theoretical periodic DFT calculations. Experiments with co-adsorption of heavy metal cations and emergent pollutants were also conducted. Interactions between the pollutants and the composite were highlighted by spectroscopic techniques.
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The synthesis and magnetochemistry of transition and lanthanide metal compoundsSmith, Charlene Amanda January 2013 (has links)
The introductory Chapter to this thesis outlines fundamental aspects of 4f lanthanide(III) coordination chemistry, in particular compounds that possess the intriguing properties of slow relaxation of magnetisation, (or the ability to behave as single-molecule magnets, SMMs). The recent renaissance into the study of the magnetic behaviour of 4f-coordination complexes has led to the consideration of utilising organometallic precursors for the development of novel lanthanide containing compounds, which may possess interesting magnetic properties, subsequently forming the basis of Chapter Two. In Chapter Two, the syntheses and structures of the novel lithiated thiolate ligand, lithium triphenylsilylthiolate, (Ph3SiS-Li) (2.1), and the sulfur-bridged, dimetallic dysprosium(III) and gadolinium(III) complexes [(MeCp)2Dy(µ-SSiPh3)]2 (2.2) and [(MeCp)2Gd(µ-SSiPh3)]2 (2.3), are described in detail. The structural and physical properties of these compounds are analysed through NMR, elemental analysis and SQUID magnetometry, alongside supporting theoretical calculations to reveal that compound 2.2 is the first dimetallic, sulfur-bridged SMM reported, giving an energy barrier to the reversal of magnetisation of Ueff = 192 ± 5 K.56bChapter Three reports on the structural development of a series of lanthanide monomers, exhibiting the general motif [Ln(OSiPh3)3(THF)3] (where Ln = Dy(3.4), Er(3.5), Ho(3.6), Gd(3.7), Tb(3.8)), exploiting the siloxide ligand Ph3SiOH through two novel synthetic routes. This Chapter also provides new analytical insight to these complexes by exploring their magnetic properties through a series of SQUID measurements and through the analysis of their electronic properties using air sensitive, variable temperature optical absorption spectroscopy. Compounds 3.4 and 3.5 were revealed to be SMMs, with 3.5 having a much higher thermal barrier to the reversal of magnetisation, Ueff = ~ 28 K, than 3.4, which are supported by theoretical analysis. Chapter Four describes the utility of ligand 2.1 and Ph3SiOH in the context of 3d transition metal cyclopentadienyl chemistry, outlining the syntheses and structures of three distinct compounds; the trimetallic, [Cp2Mn3(µ-OSiPh3)4](4.7), the hetero-cubane tetramer [CpMn(µ-SSiPh3)]4 (4.8) and the dimetallic thiolate-bridged [CpCr(µ-SSiPh3)]2 (4.9) compound. These compounds were formed in reactions exploiting organometallic manganocene and chromocene precursors. Magnetic susceptibility measurements were conducted on these compounds to gain further insight into their structural properties. The magnetic exchange coupling constants for Mn(II) compounds 4.7 and 4.8 were J = - 4.4 cm-1 and J = - 3.0 cm-1 respectively. Furthermore, having demonstrated the use of metal-cyclopentadienyl building blocks in the synthesis of novel SMMs, Chapter Five discusses the possibility of further advancement on the development of this class of magnetic molecules.
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Synthesis and characterization of quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers and reaction chemistry of the diphosphine ligand 2,3-bis(diphenylphosphino)-N-p-tolylmaleimide (bmi) at triosmium carbonyl clusters.Poola, Bhaskar 12 1900 (has links)
Quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers have been synthesized as possible specific metal host systems. The synthesis and characterization of quinoxaline-functionalized, cage-annulated oxa- and thiacrown ethers have been described. The characterization of these host systems have been fully achieved in solution by using various techniques such as IR, 1H NMR, and 13C NMR spectroscopic methods, high-resolution mass spectrometry (HRMS), elemental microanalysis, and X-ray crystallographic analysis in case of one quinoxaline-functionalized, cage-annulated oxacrown ether compound. The synthesis of the diphosphine ligand 2,3-bis(diphenylphosphino)-N-p-tolylmaleimide (bmi) is described. The substitution of the MeCN ligands in the activated cluster 1,2-Os3(CO)10(MeCN)2 by the diphosphine ligand bmi proceeds rapidly at room temperature to furnish a mixture of bridging and chelating Os3(CO)10(bmi) isomers and the ortho-metalated product HOs3(CO)9[μ-(PPh2)C=C{PPh(C6H4)}C(O)N(tolyl-p)C(O)]. Thermolysis of the bridging isomer 1,2-Os3(CO)10(bmi) under mild conditions gives the chelating isomer 1,1-Os3(CO)10(bmi), whose molecular structure has been determined by X-ray crystallography. The kinetics for the ligand isomerization have been investigated by UV-vis and 1H NMR spectroscopy in toluene solution over the temperature range of 318-348 K. On the basis of kinetic data conducted in the presence of added CO and the Eyring activation parameters, a non-dissociative phosphine migration across one of the Os-Os bonds is proposed. Orthometalation of one of the phenyl groups associated with the bmi ligand is triggered by near-UV photolysis of the chelating cluster 1,1- Os3(CO)10(bmi).
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Síntese, caracterização, modelagem molecular e ensaios antibacterianos de novos complexos de Ag(I) com ligantes biologicamente ativos / Synthesis, characterization, molecular modeling and antibacterial assays of new Ag(I) complexes with biologically active ligandsBergamini, Fernando Rodrigues Goulart, 1988- 22 August 2018 (has links)
Orientador: Pedro Paulo Corbi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T10:51:51Z (GMT). No. of bitstreams: 1
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Previous issue date: 2013 / Resumo: Neste trabalho, são descritas a síntese e a caracterização de três complexos inéditos de prata com os ligantes L-butionina sulfoximina (BSO), ácido 2-tiazolidina carboxílico (2-TC) e ácido 4-tiazolidina carboxílico (4-TC). O complexo de prata com BSO foi caracterizado por um conjunto de análises químicas e espectroscópicas, a saber: análise elementar, análise térmica, espectroscopia na região do infravermelho (IV), espectroscopia Raman, espectroscopia de ressonância magnética no estado sólido de C (C-RMN), estudos por DFT e ensaios biológicos. Os complexos de prata(I) com 2-TC e 4-TC, por sua vez, foram caracterizados por análise elementar, análise térmica, espectroscopia na região do infravermelho (IV), espectroscopia de ressonância magnética no estado sólido de C-RMN e N-RMN, estudos por DFT e ensaios biológicos. O complexo de prata com BSO, [Ag2(BSO)], apresenta uma composição 2:1 metal/ligante, sendo que a coordenação do ligante a um dos átomos de prata ocorre através dos grupamentos amino e carboxilato, enquanto que a coordenação ao segundo átomo de prata ocorre através do nitrogênio da sulfoximina. Os complexos de prata com 2-TC e 4-TC também apresentam proporção 2:1 metal/ligante, com um átomo de prata coordenado através do nitrogênio e o segundo átomo de prata coordenado através do carboxilato. As análises biológicas revelaram que os complexos [Ag2(BSO)], [Ag2(2-TC)] e [Ag2(4-TC)] são efetivos sobre cepas patogênicas Gram-positivas de Staphylococcus aureus, e cepas Gram-negativas de Escherichia coli e Pseudomonas aeruginosa / Abstract: This work deals with the synthesis and characterization of three new silver(I) complexes with the ligands Lbuthionine sulfoximine (BSO), thiazolidine-2 carboxylic acid (2-TC) and thiazolidine-4 carboxylic acid (4-TC). The silver complex with BSO was characterized by elemental and thermal analyses, infrared and Raman spectroscopies, C nuclear magnetic resonance in the solid-state (C-NMR), DFT studies and biological assays. The silver(I) complexes with 2-TC and 4-TC were characterized by elemental and thermal analyses, infrared spectroscopy, C and N nuclear magnetic resonance in the solid-state, DFT studies and biological assays. The silver-BSO complex, [Ag2(BSO)], presents a 2:1 metal/ligand ratio. One of the silver(I) ion was shown to be coordinated through the amine nitrogen atom and the oxygen of carboxylate, while the second ion was shown to be coordinated through the nitrogen atom of the sulfoximine group. The silver(I) complexes with 2-TC and 4-TC also presented a 2:1 metal/ligand ratio, and are coordinated by the nitrogen and the oxygen atom of the carboxylate group. The biological assays revealed that the [Ag2(BSO)], [Ag2(2-TC)] and [Ag2(4-TC)] complexes are active against Gram-positive pathogenic strains of Staphylococcus aureus and Gramnegative pathogenic strains of Escherichia coli and Pseudomonas aeruginosa / Mestrado / Quimica Inorganica / Mestre em Química
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Desenvolvimento de catalisadores de rutênio coordenados a toluilfosfinas para polimerização via metátese / Development of ruthenium catalysts coordinated with tolylphosphines for metathesis polymerizationMarcella de Sousa Ferreira 20 February 2014 (has links)
Este trabalho investigou a influência das propriedades estéricas e eletrônicas de ligantes ancilares em complexos do tipo [RuCl2(PR3)3] e [RuCl2(PR3)xLy], onde R = p-toluil e L = piperidina, N-butilamina e isonicotinamida, em reações de polimerização via metátese por abertura de anel (ROMP) e de copolimerização via metátese por abertura de anel (ROMCP) de norborneno (NBE) e norbornadieno (NBD). O objetivo foi observar como o efeito estéreo (dado em função do ângulo de cone, θ) e eletrônico (dado em função de pKa) da PpTol3 pode influenciar a reatividade em ROMP e ROMCP quando está sozinha ou combinada com amina. <br /> O complexo [RuCl2(PpTol3)3] (1) produziu rendimentos melhores que 70% por 10 min a 23 °C, com Mw na ordem de 104 g.mol-1 e IPD de 2,2. O melhor rendimento obtido quando o complexo [RuCl2(PpTol3)2(pip)] (2) é utilizado foi observado nas reações por 30 min a 50 °C (80,2%) com Mw de 1,5 x 105 g.mol-1. IPD de 2,0 foi obtido com 2 por 60 min a 23 °C. O complexo 2 demonstrou ser mais reativo que o complexo 1 nas reações de ROMP de NBD, com rendimento de 60,1% por 60 min a 50 °C. O impedimento estéreo de PpTol3 em 1, provavelmente é o responsável pelo melhor desempenho com NBE, com um período de indução mais curto para iniciar a ROMP. Por outro lado, o sinergismo amina→Ru→olefina deve contribuir para a ativação de NBD com 2. <br /> Os rendimentos para poliNBE com os complexos contendo N-butilamina e isonicotinamida foram de 68 e 35%, respectivamente, por 60 min a 50 °C, isso mostra que a atividade catalítica para estes complexos sobrepõe o baixo ângulo de cone da Nbutilamina e a capacidade de retrodoação da isonicotinamida. Os rendimentos para o poliNBD foram de 30,9 e 9,1, respectivamente. <br /> As reações de copolimerizações com NBE e NBD (ROMCP) foram realizadas com uma quantidade fixa de NBE ([NBE]/[Ru] = 5000) e diferentes concentrações de NBD ([NBD]/[Ru] = 1000, 2000 ou 3000), por 60 min a 50°C. Para ambos os complexos 1 e 2, os rendimentos foram acima de 80% quando aumentou-se a [NBD] e os materiais poliméricos apresentaram microestruturas lisas. Os valores de Tg (acima de 60 °C) obtidos quando o complexo 1 foi utilizado, sugerem a presença de NBD nas cadeias poliméricas. Com o complexo 2, os valores de Tg foram entre 33 e 37 °C, indicando a possibilidade de polimerização apenas do NBE. / This study investigated the influence of steric and electronic properties of ancillary ligands in complexes of the type [RuCl2(PR3)3] and [RuCl2(PR3)xLy], with R = p-tolyl and L = piperidine, N-butylamine and isonicotinamide, for ring-opening metathesis polymerization (ROMP) and ring-opening metathesis copolymerization of norbornene (NBE) and norbornadiene (NBD). The aim was to observe how the steric (in terms of the cone angle, θ) and electronic (in terms of pKa) effects of PpTol3 can tune the reactivity in ROMP and ROMCP when alone or combining with an amine. <br /> The [RuCl2(PpTol3)3] complex (1) produced yields better than 70% for 10 min at 23 °C, with Mw in the order of 104 g.mol-1 and PDI of 2,2. The best yields obtained when the complex [RuCl2(PpTol3)2(pip)] (2) was used was observed in the reactions 30 min at 50 °C (80%), with Mw of 1.5 x 105 g.mol-1. PDI of 2.0 was obtained with 2 for 60 min at 23 °C. The complex 2 proved to be more reactive than complex 1 for ROMP of NBD, with yield of 60.1% for 60 min at 50 °C. The steric hindrance of PpTol3 in 1 probable provided the difference in the reactive for NBE, with a short induction period to initiate the ROMP. However, the amine→Ru→olefin synergism in 2 probable contributed to the better activation of NBD. <br /> The yields for polyNBE with the N-butylamine and isonicotinamide derivative complexes were 68 and 35%, respectively, for 60 min at 50 °C., it shows that the catalytic activity of these complexes to overlap the low cone angle of the N-butylamine and the ability of the backdonation of the isonicotinamide. Proceeds to poliNBD were 30.9 and 9.1, respectively. <br /> Copolymerizations with NBE and NBD (ROMCP) were performed with a fixed quantity of NBE ([NBE]/[Ru] = 5000) and different concentrations of NBD ([NBD]/[Ru] = 1000, 2000 or 3000), for 60 min at 50 ° C. The yields were better than 80% when increasing the [NBD] and the polymeric materials showed smooth microstructures. The obtained Tg values (60 °C) obtained when the complex 1 was used, indicated the presence of NBD in the polymer chains. With the complex 2, the Tg values were in the range of 33 - 37 °C, indicating the possibility of polymerization of only NBE.
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Synthesis and Characterization of Transition Metal Ion-based Hydrogels with Auxiliary Carboxylate Spacer Ligands for Selective Carbon Dioxide Separation and Other Potential ApplicationsAl Dossary, Mona 11 1900 (has links)
Metallo-supramolecular hydrogels have interesting dynamic properties for many applications. We report a simple method for synthesizing copper-based polymer hydrogels made from nontoxic poly(methyl vinyl ether-alt-maleic anhydride) (PVM-alt-MA) in the absence or presence of added dicarboxylates, such as adipate and terephthalate. We utilize metal-polycarboxylate backbone and carboxylate spacer ligands between polymers strands engineered via non-covalent metal ion coordination. Rheological measurements revealed that the mechanical stability of the hydrogels was enhanced by the addition of supplementary dicarboxylate ligands. The optimal ratio of polymer to dicarboxylate to Cu2+ was 10:4:2.5. Our scanning electron microscope (SEM) and Cryo-SEM imaging and physical adsorption measurements revealed the formation of pores. The Brunauer–Emmett–Teller (BET) surface area of the dried hydrogels increased from 177.96 m2 g−1 in a dried hydrogel without added dicarboxylate to 646.90 and 536.44 m2 g−1 with the addition of adipate and terephthalate, respectively. The pore volume increased as well.
Separation of CO2 from post-combustion flue gases is important for environmental and economic sustainability. The PVM-alt-Na-MA:adipate:Cu2+ hydrogels are promising material for post-combustion CO2 separation. At normal conditions (298 K and 1 bar), the PVM-alt-Na-MA:adipate:Cu2+ hydrogel samples with 10:4:2.5 ratio, showed notable CO2/N2 selectivity of 78.46 and a high CO2/CH4 selectivity
reaching 26.09 at 1 bar. Additionally, we investigated in detail the effect of transition metal ion on the rigidity and structure of hydrogels using Al3+, Fe3+, Cu2+, Ni2+, Zn2+, and Co2+. We also studied the effect of using tricarboxylate spacer ligands such as nitrilotriacetic (NTA) and trisodium citrate or tetracarboxylate such as ethylenediaminetetraacetic acid (EDTA).
It is important to mention that one of the main advantages of our facile synthesis method is being simple and can be scaled up for commercial applications. For scaling up the synthesis of hydrogels, we utilized a filling machine that is able to increase the amount of hydrogel aliquots with variable volume. Silver-based hydrogels showed significant antibacterial activity, due to the presence of silver nanoparticles. We utilized a filling machine for application of amorphous wound dressing. The optimization of the conditions of the filling enabled us to scale up the synthesis and the filling process.
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