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Journal articles on the topic "GENERATION DENDRIMERS"
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Milenin, Sergey A., Elizaveta V. Selezneva, Pavel A. Tikhonov, Viktor G. Vasil’ev, Alexander I. Buzin, Nikolay K. Balabaev, Andrey O. Kurbatov, et al. "Hybrid Polycarbosilane-Siloxane Dendrimers: Synthesis and Properties." Polymers 13, no. 4 (February 17, 2021): 606. http://dx.doi.org/10.3390/polym13040606.
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A series of carbosilane dendrimers of the 4th, 6th, and 7th generations with a terminal trimethylsilylsiloxane layer was synthesized. Theoretical models of these dendrimers were developed, and equilibrium dendrimer conformations obtained via molecular dynamics simulations were in a good agreement with experimental small-angle X-ray scattering (SAXS) data demonstrating molecule monodispersity and an almost spherical shape. It was confirmed that the glass transition temperature is independent of the dendrimer generation, but is greatly affected by the chemical nature of the dendrimer terminal groups. A sharp increase in the zero-shear viscosity of dendrimer melts was found between the 5th and the 7th dendrimer generations, which was qualitatively identical to that previously reported for polycarbosilane dendrimers with butyl terminal groups. The viscoelastic properties of high-generation dendrimers seem to follow some general trends with an increase in the generation number, which are determined by the regular branching structure of dendrimers.
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Gajjar, Dhaval G., Rinkesh M. Patel, Hema N. Patel, and Pravinkumar M. Patel. "Designing, characterization, and thermal behavior of triazine-based dendrimers." Journal of Polymer Engineering 35, no. 1 (January 1, 2015): 41–52. http://dx.doi.org/10.1515/polyeng-2014-0123.
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Abstract Different generations of dendritic architecture with piperazine in core moiety and hydroxyl groups on the periphery were designed by divergent method. 1,4-biz(4,6-trichloro-1,3,5-triazin-2-yl)piperazine was synthesized as a core for dendrimer synthesis. Dendrimer was then grown to G3 from core compound using diethanolamine and cyanuric chloride as branching units. Dendrimer generations were characterized by infrared (IR) spectroscopy [Fourier transform IR (FTIR)], 1H-nuclear magnetic resonance (NMR), 13C-NMR, electrospray ionization-mass spectrometry (ESI-MS), and elemental analysis. The thermal behavior of both full- and half-generation dendrimers was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA study revealed that dendrimer generations had a moderate thermal stability. Chlorine-terminated half-generation dendrimers were thermally more stable than hydroxyl-terminated full-generation dendrimers. The DSC technique was employed to determine the glass transition temperatures (Tg) of dendrimer generations. It was observed that the glass transition temperatures of synthesized dendrimer generations were of low value, which is similar to the values reported for the polyamidoamine (PAMAM) dendrimer of the same generation. It was also observed that, with the increase in the molecular weight or generation number of dendrimer, the glass transition temperature was also increased.
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Rajakumar, Perumal, and Devaraj Anandkumar. "Photophysical and Electrochemical Properties and Anticancer Activities of Porphyrin-Cored Fluorenodendrimers Synthesized by Click Chemistry." Synlett 29, no. 15 (August 14, 2018): 1995–2000. http://dx.doi.org/10.1055/s-0037-1610218.
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A new class of porphyrin-cored fluorenodendrimers were synthesized by a convergent approach through click chemistry. The zeroth-, first-, and second-generation porphyrin-cored fluorenodendrimers were characterized by means of 1H and 13C NMR spectroscopy, UV-vis spectroscopy, fluorescent spectroscopy, elemental analysis, and MALDI-TOF mass spectrometry. The UV-vis spectrum of the dendrimers showed an increase in the absorption intensity on increasing the dendrimer generation, and a bathochromic shift was observed for higher-generation dendrimers compared with lower-generation dendrimers. The dendrimers showed emission bands at 317, 604–668, and 617–668 nm, the intensity of which increased with increasing dendrimer generation. All the synthesized dendrimers exhibited a reversible oxidation potential in cyclic voltammetry. The therapeutic efficacy of the porphyrin-cored fluorenodendrimers for the inhibition of a growth tumor cell (PA-1) increased with increasing generation number of the dendrimer.
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Rajakumar, Perumal, Nagarathinam Venkatesan, Karuppannan Sekar, Subramani Nagaraj, and Ramasamy Rengasamy. "Synthesis, Optical, and Antioxidant Studies of Anthraquinone-core-based Dendrimers with N-Phenylcarbazole as Surface Group." Australian Journal of Chemistry 67, no. 4 (2014): 636. http://dx.doi.org/10.1071/ch13521.
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Synthesis of hyperbranched dendrimers up to third generation with N-phenylcarbazole as surface group and anthraquinone as the core unit has been achieved. The fluorescence decay studies of the dendrimers indicate that generation growth alters the relaxation time. The highly branched third-generation dendrimer has a longer relaxation time than the zero-, first-, and second-generation dendrimers. Similarly, higher-generation dendrimers show better antioxidant behaviour with 1,1-diphenyl-2-picryl hydrazyl than the lower-generation dendrimers.
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Sathiya Savithri, Jothinathan, and Perumal Rajakumar. "Synthesis, photophysical, antibacterial and molecular docking studies on aromatic ring core-containing rhodamine B decorated triazole bridged dendrimers." New Journal of Chemistry 42, no. 24 (2018): 19390–99. http://dx.doi.org/10.1039/c8nj02943a.
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Rhodamine B decorated dendrimers 1–6 were synthesized by a convergent approach using click chemistry. The zeroth generation dendrimer 1 (G0) and the first generation dendrimer 4 (G1) showed better antibacterial activity than the other dendrimers.
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Dwivedi, Nitin, Balak Das Kurmi, Prashant Kesharwani, and Jigna Shah. "GENERATION DEPENDENT TARGETING POTENTIAL OF DONEPEZIL LOADED POLY (PROPYLENEIMINE) DENDRIMER THROUGH GOAT NASAL MUCOSA." International Journal of Pharmacy and Pharmaceutical Sciences 10, no. 12 (December 1, 2018): 80. http://dx.doi.org/10.22159/ijpps.2018v10i12.29912.
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Objective: In the domain of nano drug delivery, dendrimers are the most explored bioactive polymeric carrier system. The present work was aimed to study the diffusion potential of different generations of Poly (propyleneimine) (PPI) dendrimers on goat nasal mucosa in an ex vivo study and synthesize a stable dendrimer for olfactory drug delivery.Methods: The generations (3.0G, 4.0G, and 5.0G) of PPI dendrimer were synthesized, and PEGylated by MPEG 5000 and then loaded with donepezil. A comparative study was carried out among all generations in term of their drug loading capacity, stability, sustained release behaviour as well as for targeting efficacy. An ex-vivo study was carried out on Franz Diffusion Cell with goat nasal mucosa.Results: The developed G3, G4, and G5 dendrimerformulations had entrapment efficiency of 24.33±0.56%, 40.12±0.62%, and 60.4±0.6%, respectively. The nasal diffusion study revealed that 5.0G PPI dendrimer increased diffusion of donepezil up to 47% as compared to the pure solution of donepezil while 10% improvement in diffusion was seen as compared to 4.0 G PPI dendrimer. Thus obtained results claimed that the drug loading as well as targeting potential of PPI dendrimers increased with the increase in the number of generation. The investigation outcome indicated promising results of 5.0G PPI dendrimer over the 3.0G and 4.0G PPI dendrimer generations for their drug loading capacity, stability, and sustained release action.Conclusion: The 5.0G PPI dendrimer proved its superior candidature over the other lower generations of PPI dendrimers for drug delivery and drug targeting.
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Salamończyk, Grzegorz M. "A Fast and Convenient Synthesis of New Water-Soluble, Polyanionic Dendrimers." Molecules 26, no. 16 (August 6, 2021): 4754. http://dx.doi.org/10.3390/molecules26164754.
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Reasonably simple, efficient, and possessing aspects of generality, the methodology for the synthesis of new, water-soluble, dendrimeric polyesters with great potential applications as antiviral drugs in their own right is described. The essential aspect of the presented approach is a quite unique, immediate access to the polyanionic material at each generation during divergent synthesis. Six target polyanionic dendrimers (generations 1, 2, and 3) have been synthesized. The key monomers applied in this project were 1,3,5-benzenetricarboxylic acid derivatives, which also worked as direct precursors of the charged dendrimer surface.
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Ashrafi, Frydon, Tahereh Mahbobi, and Ashraf Sadat Ghasemi. "Computational study adsorption of mercaptopurine in generation G3 and G5 PAMAM dendrimers." Ciência e Natura 37 (December 21, 2015): 12. http://dx.doi.org/10.5902/2179460x20822.
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Due to its unique properties of dendrimers as well as with high-level groups, a special ability to carry drugs. In this study compared the interaction between the two generations of poly (amidoamine) PAMAM (G3and G5) dendrimers and the drug 6-mercaptopurine (6-MP) and the drug entrapment within the structure of dendrimers the electrostatic and covalent complexation of drugs to the dendrimer surface have been studied. The use of drug-dendrimer complex enhanced drug solubility and bioavailability of the drug.
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Ficker, Mario, Valentina Paolucci, and Jørn B. Christensen. "Improved large-scale synthesis and characterization of small and medium generation PAMAM dendrimers." Canadian Journal of Chemistry 95, no. 9 (September 2017): 954–64. http://dx.doi.org/10.1139/cjc-2017-0108.
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Dendrimers are promising polymers for biomedical applications; however, most dendrimer formulations have failed to move from laboratory science to upscaled products for preclinical testing or GMP production. This publications reports on an improved large-scale PAMAM dendrimer synthesis that is suitable to manufacture large amounts of highly pure and monodisperse dendrimers of generations G0–G5. Furthermore, an extended analytical guideline how to characterize PAMAM dendrimers with NMR, HPLC, SEC-MALS, ESI, MALDI, UV–vis, fluorescence, and IR spectroscopy is provided.
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Sabirov, Denis, Alina Tukhbatullina, and Igor Shepelevich. "Information Entropy of Regular Dendrimer Aggregates and Irregular Intermediate Structures." Liquids 1, no. 1 (March 5, 2021): 25–35. http://dx.doi.org/10.3390/liquids1010002.
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Dendrimer molecules and aggregates are chemical structures with regular branching that underlies their physicochemical properties. Regular dendrimers have been studied both theoretically and experimentally, but the irregular intermediate structures between the dendrimers of neighboring generations have not. In the present work, dendrimer aggregates, both regular and intermediate, are investigated in terms of the information entropy approach. As found, the information entropy of the regular dendrimer asymptotically increases with the generation number; herewith, its maximal value equals 2. The intermediate structures have been studied for the growing dendrimer G1 → G2 → G3 → G4 with the tricoordinated building block. The plot of the information entropy of the growing dendrimer on the size has the frontier consisting of the lowest values that correspond to the regular and irregular structures described with the symmetrical graphs. Other intermediate structures have information entropies higher than the regular dendrimers. Thus, to move the system from one informationally stable state to another, its information capacity must be temporarily increased.
Dissertations / Theses on the topic "GENERATION DENDRIMERS"
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Dotson, Michael Edward. "Improvements in Pamam Dendrimer Synthesis." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin998323664.
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Komurcu, Ramazan. "Tryptamine terminated 1st generation polyamide dendrimer synthesis and drug release /." Akron, OH : University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1196653318.
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Thesis (M.S.)--University of Akron, Dept. of Chemical Engineering, 2007."December, 2007." Title from electronic thesis title page (viewed 02/25/2008) Advisor, Stephanie T. Lopina; Faculty readers, Bi-min Newby, Helen Qammar; Department Chair, Lu-Kwang Ju; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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An, Min. "UNDERSTANDING DNA CONDENSATION BY LOW GENERATION (G0/G1) AND ZWITTERIONIC G4 PAMAM DENDRIMERS." UKnowledge, 2016. http://uknowledge.uky.edu/chemistry_etds/58.
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Cationic polymers have shown potential as gene delivery vectors due to their ability to condense DNA and protect it from cellular and restriction nucleases. Dendrimers are hyperbranched macromolecules with precisely defined molecular weights and highly symmetric branches stemming from a central core. The nanosize, tunable surface chemistries and ease of surface functionalization has made dendrimers an attractive alternative to conventional linear polymers for DNA delivery applications. The commercially available, cationic dendrimer poly(amidoamine) or PAMAM is the most widely studied dendrimer for use as a gene delivery vector. The aim of this dissertation is to provide an increased understanding of the packaging and forces within PAMAM–DNA complexes.
In Chapter 4, we will discuss the effect of molecular chain architecture on DNA-DNA intermolecular forces by examining DNA condensed by low generation (G0 & G1) PAMAM and comparing them to comparably charged linear arginine peptides. Using osmotic stress coupled with X-ray scattering, we are able to determine the structure and forces within dendrimer-DNA complexes, or dendriplexes. We show that PAMAM–DNA assemblies display significantly different physical behavior than linear cation–DNA assemblies. In Chapter 5, we examine the role of pH on condensation in these same low generation PAMAM-DNA complexes. PAMAM dendrimers have both terminal primary amines and internal tertiary amines with different pKas of approximately 9 and 6, respectively. We show changes in the pH at condensation greatly influence the resulting packaging as well as the resulting phase behavior for PAMAM dendriplexes. In Chapter 6, we examine the packaging of DNA by G4 PAMAM as a function of the percent zwitterionic modification. Many cationic polymers, including PAMAM, have shown high transfection efficiency in cell culture and potential for in vitro and in vivo applications, but its development is hindered by cytotoxicity in many cell lines and tissues. We hypothesize that zwitterionic PAMAM (zPAMAM) represent a new means to tune polymer-DNA interactions through PAMAM surface charge potentially enhancing intracellular unpackaging while reducing cellular toxicity. These zPAMAM complexes are currently under investigation for their potential as safer and more efficient materials for DNA delivery.
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Yonkeu, Anne Lutgarde Djoumessi. "Dendritic poly(3-hexylthiophene) star copolymer systems for next generation bulk heterojunction organic photovoltaic cells." University of the Western Cape, 2018. http://hdl.handle.net/11394/6662.
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Philosophiae Doctor - PhDThe continuous increase in energy consumption and decrease in fossil fuels reserves are a primary concern worldwide; especially for South Africa. Therefore, there is an urgent need for alternative energy resources that will be sustainable, and environmentally friendly in order to tackle the ecological degradation generated by the use of fossil fuels. Among many energy ‘niches’, solar energy appears to be one of the most promising and reliable for the African continent because of the constant availability of sun light. Organic conjugated polymers have been identified as suitable materials to ensure proper design and fabrication of flexible, easy to process and cost-effective solar cells. Their tendency to exhibit good semiconducting properties and their capability to absorb photons from the sunlight and convert it into electrical energy are important features that justify their use in organic photovoltaic cells. Many different polymers have been investigated as either electron donating or electron accepting materials. Among them, poly(3-hexylthiophene) is one of the best electron donor materials that have been used in organic photovoltaic cells. It is a good light absorber and its Highest Occupied Molecular Orbital (HOMO) energy level is suitable to allow electron transfer into an appropriate electron acceptor. On the other hand, the molecular ordering found in dendrimers attracted some interest in the field of photovoltaics as this feature can ensure a constant flow of charges. In this work, I hereby report for the first time, the chemical synthesis of a highly crystalline dendritic star copolymer generation 1 poly(propylene thiophenoimine)-co-poly(3-hexylthiophene) (G1PPT-co-P3HT) with high molecular weight and investigate its application as donating material in bulk heterojunction organic photovoltaics.
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Bolton, Katherine. "Gene delivery with amphiphilic lower generation polypropylenimine dendrimer." Thesis, University of Strathclyde, 2007. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21936.
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In this work a novel lower generation amphiphilic polypropylenimine (PPI) dendrimer with good aqueous solubility was developed and tested as a gene delivery agent. PPI dendrimer generation 3 (DAB-16-Am) was substituted with a low level of cetyl chains (less than 5 molar percent) by reaction with 1-bromohexadecane under carefully controlled conditions. Structural characterisation was carried out using nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. Cetylated DAB-16 spontaneously self-assembled in an aqueous environment and in the presence of cholesterol (50% w/w) formed unilamellar vesicles of approximately 50nm in diameter. Cetylation tripled the DNA binding capacity of the dendrimer, supporting the hypothesis that the presence of hydrophobic alkyl chains would improve the packaging of DNA by the dendrimer. Apparent DNA binding enthalpies were also significantly more favourable. The size, surface charge and morphologies of the resulting complexes were found to be dependent upon the composition of the dendrimer. Cetylated dendrimer was able to stabilise complexes against electrostatic disruption but differing biophysical characteristics of complexes did not influence the protection of DNA against nuclease activity. The introduction of hydrophobic moieties increased the haemolytic potential of the dendrimer and enhanced cytotoxic effects in three immortalised cell lines. Cetylated DAB-16 formulations were able to transfect these cell lines although the dendrimer dose applied to cells must balance intracellular access and toxicity. Cetylated DAB-16 was also well tolerated when administered intravenously at doses required for in vivo gene delivery. These features suggest that cetylated DAB-16 has a potential application in anti-tumour gene therapy.
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Komurcu, Ramazan. "TRYPTAMINE TERMINATED 1st GENERATION POLYAMIDE DENDRIMER:SYNTHESIS AND DRUG RELEASE." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1196653318.
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Gaab, Manuela. "Second generation Trisoxazolines : new polydentate and recyclable dendritic ligands for asymmetric catalysis." Strasbourg, 2009. https://publication-theses.unistra.fr/public/theses_doctorat/2009/GAAB_Manuela_2009.pdf.
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Le présent travail, axé sur un élargissement et une optimisation des applications des ligands de type tris(oxazolinyl)ethane (trisoxazolines) en catalyse asymétrique « acide de Lewis », présente une panoplie de nouveaux ligands stéréodirecteurs multidentates et porteurs de fonctions capables de permettre d’ultérieurs connexions ou autre greffage (« linkers »). Basé sur la préparation (à l’échelle du gramme) de précurseurs fonctionnalisés de la classe des alcools aminés appropriés, trois dérivés chiraux pentadentates de symétrie C1 et deux dérivés hexadentates de symétrie C3 de la famille des trisoxazolines, incorporant des fonctions (thio)ether, ont pu être synthétisés. Conférant de meilleures stabilités cinétiques envers les métaux labiles comme les lanthanides, ces nouveaux ligands sont alors supposés fournir des applications plus efficaces dans les transformations stéréosélectives. Les bis- et trisoxazolines contenant une fonction alkynyl ont pu être greffées de façon covalente à des supports dendritiques de type carbosilane et le potentiel catalytique des complexes de cuivre(II) de ces nouveaux ligands polydispersés a pu être examiné au travers de l’étude de deux réactions de référence. Pour chacune de ces réactions, les catalyseurs multisites de type bisoxazoline montrent une meilleure sélectivité et plus particulièrement, une activité catalytique supérieure. Cette observation peut être interprétée comme étant due à une gêne dans la décoordination de la troisième unité oxazoline, représentant l’étape clé pour la génération de l’espèce catalytiquement active pour les complexes de cuivre porteurs de ligands trisoxazoline immobilisés. Les catalyseurs dendritiques de seconde génération ont été encapsulés dans des sachets à membranes de dialyse. Ainsi, les réactions catalytiques ont pu être effectuées en immergent ces « sachets catalytiques » dans un récipient contenant une solution de substrat. Les catalyseurs contenant les unités bisoxazoline ont ainsi conduits à de bons résultats reproductibles après plusieurs recyclages, alors que la performance des dendrimères contenant les ligands trisoxazoline diminue de manière monotone au fil des tours catalytiques en raison de leur faible activité, nécessitant alors une augmentation du temps de réaction après chaque cycle. Par conséquence, ceci engendre une perte plus importante du catalyseurIn this work, directed towards more efficient and broadened applications of tris(oxazolinyl)ethanes (trisoxazolines) in asymmetric Lewis acid catalysis, a library of new stereodirecting polydentate and linker-functionalised ligands was designed. On the basis of a multigramm-scale access to appropriately functionalised α-amino alcoholprecursors, three C1-chiral pentadentate and two C3-symmetric hexadentate trisoxazoline derivatives, incorporating peripheral (thio)ether functions, were synthesised. Conferring greater kinetic persistence to labile metals such as lanthanides, they are assumed to allow efficient applications in stereoselective transformations. Bis- and trisoxazolines containing an alkynyl unit have been covalently attached to carbosilane dendrimers and the general catalytic potential of their CuII-complexes was assessed by studying two benchmark reactions. For both of them, the bisoxazoline-based multisite catalysts displayed superior selectivity and, in particular, catalyst activity. The latter was interpreted as being due to the hindered decoordination of the third oxazoline unit, the key step in the generation of the active catalyst, in the immobilised trisoxazolinecopper complexes. Second generation dendrimer catalysts were immobilised in dialysis membrane bags, allowing to effect catalytic conversions by dipping them into substrate-filled reaction vessels. The bisoxazoline-based catalysts gave good and reproducible results after several recyclings, whereas the performance of the trisoxazoline dendrimers decreased monotonically due to their low activity, which necessitated an increased reaction time for each cycle. This resulted in higher levels of catalyst leaching
Im Rahmen dieser Arbeit wurde, mit dem Ziel Tris(oxazolinyl)ethanderivate (Trisoxazoline) in der asymmetrischen Lewissäure-Katalyse effizienter und breiter anzuwenden, eine Serie neuer polydentater und Linker-funktionalisierter Steuerliganden synthetisiert. Basierend auf einem Zugang zu entsprechend funktionalisierten α-Aminoalkoholvorstufen im Multigramm-Maßstab wurden drei C1-chirale pentadentate und zwei C3-symmetrische hexadentate Trisoxazolinderivate mit peripheren (Thio)etherfunktionen synthetisiert. Diese tragen im Prinzip zur kinetischen Stabilisierung labiler Metalle, z. B. Der Lanthanoiden, bei und ermöglichen so deren effiziente Anwendung in stereoselektiven Reaktionen. Nach der kovalenten Trägerung Alkinyl-funktionalisierter Bis- und Trisoxazoline an Carbosilandenrimeren wurde das katalytische Potential ihrer CuII-Komplexe in zwei Benchmarkreaktionen abgeschätzt. Bisoxazolin-basierte Vielzentrenkatalysatoren erzielten mit beiden Systemen höhere Selektivitäten und insbesondere Aktivitäten als ihre Trisoxazolinanaloga. Dies wurde auf die gehinderte Dekoordination des dritten Oxazolins, dem Schlüsselschritt bei der Ausbildung des aktiven Katalysators im Falle der immobilisierten Trisoxazolin-Kupferkomplexe, zurückgeführt. Dendritische Katalysatoren der zweiten Generation wurden in einer Dialysemembran immobilisiert, um durch Eintauchen der resultierenden Beutel in mit Substrat befüllte Reaktionsgefäße katalytische Umsetzungen durchzuführen. Dabei erzielten die Bisoxazolinbasierten Katalysatoren über mehrere Läufe gute, reproduzierbare Werte, während jene der Trisoxazolindendrimere monoton abnahmen. Dies ließ sich auf ihre geringe Aktivität, die damit verbundenen längeren Reaktionszeiten und die erhöhten Katalysatorverluste durch Leaching zurückführen
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Aloisi, Adriano. "Nanoparticles based on different generation adamantane dendrons : design, synthesis and self-assembly studies." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF062.
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L’adamantane est un hydrocarbure polycyclique, rigide et assez encombrant. En médecine, plusieurs dérivés à base d’adamantane ont été développés notamment comme agent antiviraux. Facilement fonctionnalisés, sa conformation 3D permet d’amoindrir les encombrements stériques entre les différents groupements fonctionnels. Nous avons décidé d’utiliser ses propriétés pour concevoir des structures plus complexes, à savoir, des dendrons et des foldamers. Les dendrons sont des polymères synthétiques possédant des propriétés intéressantes. De par leurs tailles, ils sont considérés comme des nanoparticules et possèdent un ciblage passif des cellules cancéreuses. De plus, facilement fonctionnalisés ils peuvent être utilisés comme molécule cargo dans la vectorisation de principes actifs. Outre la vectorisation, les dendrons permettent d’améliorer les propriétés physico-chimiques d’un médicament (absorption, distribution, métabolisme, élimination et toxicité). Nous avons alors choisi de concevoir des dendrons à base d’adamantane. Ces derniers ont la particularité de ne pas posséder d’espaceur entre les molécules d'adamantane se qui les rend hautement rigides. L’analyse par microscopie électronique à transmission de différents dendrons a permis d’étudier leurs morphologies selon leurs fonctionnalisations ainsi que l’effet du solvant, de la concentration et du support sur leurs auto-assemblages. Dans un second temps, nous avons conçu un acide aminé basé sur l’adamantane. Cet acide g-aminé a ensuite été incorporé dans des séquences peptidiques et les effets de l’adamantane sur la structure secondaire des peptides ont été étudiés par dichroïsme circulaireAdamantane is a polycyclic hydrocarbon, rigid and quite bulky. In medicine, several adamantane-based derivatives have been developed especially as antiviral agents. Easily functionalized, its 3D well-defined structure considerably decrease the sterical hindrance between its different functional groups. In this context, we decided to use adamantane to build more complex structures such as dendrons and foldamers. Dendrons are synthetic polymers with interesting properties. Because of their size, they are considered as nanoparticles and possess a passive cancer cell targeting. In addition,they are easily functionalized and can be use as vector of drugs. Indeed, the dendrons improve the physochemical properties of a drug (absorption, distribution, metabolism, elimination and toxicity). We decided to combine adamantane and dendrons to build adamantane-based dendrons. However, these dendrons have the particularity of not having spacer between the adamantane moieties, thus, they are highly rigid. Transmission electron microscopy analysis of the different functionalized dendrons allowed to study their self-assembly capacity and their morphology according to their functional groups,the solvent, the concentration and the support. In a second step, we designed an amino acid based on adamantane. This g-amino acid has been introduced in a peptide backbone using solid phase peptide synthesis. Then, the effects of adamantane onto peptide secondary structures have been studied by circular dichroism
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Weng, Jing-Ting, and 翁靖婷. "Supramolecular Chemistry and Nanotechnology of Low Generation Amphiphilic Dendrimers (AD)." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/n39jkt.
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碩士國立交通大學
應用化學系碩博士班
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In this research, low generation amphiphilic dendrimers, PAD1 and PAD2, which have inner hydrophilic core and outer hydrophobic shell, were first successfully synthesized by connecting a pentaerythritol core with four amphiphilic arms. The difference between PAD1 and PAD2 is the joint fragment connecting hydrophilic core and hydrophobic linker. In PAD1, the two parts are bonded by a rigid and planar benzene ring, whereas in PAD2, they are bonded by a more soft and non-planar sp3 carbon(C). Part 1. Preparation of Soft Nano-Cylinders via Polymerization in Amphiphilic Dendrimers The molecule was used as a nano-reactor to produce uniform polymer particles because the core provides cavity to encapsulate hydrophilic guest molecules. By polymerizing hydrophilic (hydroxyethyl)methacrylate (HEMA) in the PAD1, amphiphilic nano-cylinders, denoted as PAD1-NPs, which contain hydrophilic poly(HEMA) body and hydrophobic aliphatic tips, were produced. NMR spectra, GPC, MASS and SAXS characterizations were used to confirm that the PAD1-NPs were produced via nano-emulsion polymerization. Moreover, the SAXS results show that PAD1-NPs are uniform nano-cylinders with diameter of 1.9 nm and length of 4.0 nm. The concept of nano-emulsion polymerization thus breaks the lowest size limitation of the conventional emulsion polymerization and facilitates the formation of unique amphiphilic polymer nano-particles(PAD1-NPs). Part 2. Influences of Linker Units on the Self-Assembled Morphology of Amphiphilic Dendrimers In this part, encapsulation behavior of the amphiphilic dendrimers with different hydrophobic linker group, PAD1 and PAD2, was studied. This research reveals the self-assembly behavior of PAD1 and PAD2 with different solvent as guest. SAXS results reveal the similar solution topological behavior that both micelles exhibit non-specific shape. After encapsulating guest molecules, they turn into cylindrical micelles. Solid-state XRD results reveal the opposite assembly behavior after solvent added. With added solvent, PAD1 turns from hexagonal columnar phase into a disordered phase, whereas, for PAD2, the added solvent turns the amorphous PAD2 into ordered LC phase.
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"Generation-independent dimerization behavior of quadruple hydrogen bond-containing oligo(benzyl ether) dendrons." 2006. http://library.cuhk.edu.hk/record=b5892931.
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Wong Chun Ho.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.
Includes bibliographical references (leaves 72-77).
Abstracts in English and Chinese.
Contents --- p.i
Acknowledgments --- p.iii
Abstract --- p.iv
Abbreviations and acronyms --- p.vi
Publications originated from the work of this thesis --- p.viii
Chapter Chapter 1 - --- Dendritic Macromolecules and Dendronized Polymers
Chapter 1.1 --- Introduction to Dendrimers and Dendronized Polymers --- p.1
Chapter 1.2 --- Overview of the Synthesis of Dendronized Polymers --- p.4
Chapter 1.2.1 --- Graft-from Approach --- p.4
Chapter 1.2.2 --- Graft-to Approach --- p.5
Chapter 1.2.3 --- Macromonomer Approach --- p.6
Chapter 1.2.3.1 --- Step Growth Polymerization --- p.6
Chapter 1.2.3.2 --- Chain Growth Polymerization --- p.8
Chapter 1.2.3.3 --- Supramolecular Polymerization --- p.9
Chapter Chapter 2 - --- En Route to Hydrogen Bond-Mediated. Supramolecular Dendronized Polymers
Chapter 2.1 --- Design of Supramolecular Dendronized Polymers --- p.15
Chapter 2.1.1 --- Binding Modes in Supramolecular Polymers --- p.15
Chapter 2.1.1.1 --- Hetero-Complementary Polymerization --- p.16
Chapter 2.1.1.2 --- Self-Complementary Polymerization --- p.17
Chapter 2.1.2 --- The Effect of Binding Constant on the Degrees of Polymerization --- p.18
Chapter 2.1.3 --- The Effect of Dimerization Constant on the Molecular Weight Distribution --- p.21
Chapter 2.1.4 --- The Dendritic Effect on the UPy Binding Behavior --- p.21
Chapter 2.2 --- Summary --- p.24
Chapter Chapter 3 - --- "Design, Synthesis, and Structural Characterization of Dendronized Dimers"
Chapter 3.1 --- Design of Dendronized Dimers --- p.25
Chapter 3.1.1 --- The Nature of R and R on the Dimerization Behavior --- p.25
Chapter 3.1.2 --- Selection of Dendrons --- p.26
Chapter 3.1.3 --- Positioning of Dendrons and the Synthetic Feasibility --- p.27
Chapter 3.2 --- Synthesis of Dendronized Dimers --- p.28
Chapter 3.3 --- Characterizations of the Intermediates and Target Dimers --- p.31
Chapter 3.3.1 --- 1H NMR Spectroscopy --- p.31
Chapter 3.3.2 --- 13C NMR Spectroscopy --- p.38
Chapter 3.3.3 --- Mass Spectrometry --- p.41
Chapter 3.3.4 --- Vapor Pressure Osmometry --- p.43
Chapter 3.3.5 --- Infrared Spectroscopy --- p.43
Chapter 3.3.6 --- Gel Permeation Chromatography --- p.44
Chapter 3.4 --- Conclusions --- p.46
Chapter Chapter 4 - --- Determination of Dimerization Constants
Chapter 4.1 --- Overview of the Self-Assembling Process in UPy System --- p.47
Chapter 4.2 --- Determination of the Dimerization Constants (Kdim*) --- p.49
Chapter 4.2.1 --- Dimerization Constants in CDCl3 at 25 °C --- p.50
Chapter 4.2.2 --- Dimerization Constants in 10% (v/v) DMSO-d6/CDCl3 at 25 °C --- p.53
Chapter 4.2.3 --- Dimerization Constants in CDCl3 at 50 °C --- p.56
Chapter 4.3 --- Heterodimerization Experiment --- p.56
Chapter 4.4 --- Conclusions --- p.57
Chapter Chapter 5 - --- Experimental Procedures
Chapter 5.1 --- General Information --- p.60
Chapter 5.2 --- General Synthetic Procedures --- p.61
Chapter 5.3 --- Experimental Procedures --- p.62
References --- p.72
Appendix
NMR Spectra --- p.78
GPC results --- p.119
Book chapters on the topic "GENERATION DENDRIMERS"
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Wang, Hui, Hong Chang, Qiang Zhang, and Yiyun Cheng. "Fabrication of Low-Generation Dendrimers into Nanostructures for Efficient and Nontoxic Gene Delivery." In Topics in Current Chemistry Collections, 217–32. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-77866-2_8.
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Khosroshahi, M. E., M. Tajabadi, Sh Bonakdar, and V. Asgari. "Synthesis and Characterization of SPION Functionalized third Generation dendrimers Conjugated by Gold Nanoparticles and Folic acid for Targeted Breast Cancer Laser Hyperthermia: An Invitro-assay." In IFMBE Proceedings, 823–26. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19387-8_201.
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Teobaldi, Gilberto, and Francesco Zerbetto. "Dynamics of Eosin Y Encapsulated in a Fourth Generation Functionalised POPAM Dendrimer." In Organic Nanophotonics, 207–16. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0103-8_19.
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Tomalia, Donald A. "Some examples of dendrimer synthesis." In Polymer Chemistry. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198503095.003.0012.
Full textAbstract:
Dendrimers are highly branched macromolecules with unique structural properties. They may be thought of as core–shell type macromolecules wherein they amplify their mass and terminal groups as a function of growth stages. These growth stages are referred to as generations (i.e. G= 0, 1, 2, . . .). They possess three key architectural features: (i) a core region; (ii) interior shell zones containing cascading tiers of branch cells (generations) with radial connectivity to the initiator core; and (iii) an exterior or surface region of terminal moieties attached to the outermost generation. With this architecture, a careful choice of building blocks and functional groups can provide control over shape, dimensions, density, polarity, reactivity, and solubility. One of the earlier dendrimers made, using a divergent strategy, is the Starburst® poly(amidoamine) (PAMAM) dendrimer family (Scheme 1). This method involved assembling repeat units to introduce branch cells around the initiator core through successive chemical reactions at the periphery of the growing macromolecule. The first step of PAMAM synthesis involves Michael addition of four moles of methyl acrylate to the nucleophilic ethylenediamine core. This leads to an electrophilic carbomethoxy surface, which is then allowed to react with an excess of 1,2-diaminoethane to give a nucleophilic surface at generation zero. Reiteration of these two steps now involves addition of 8 mol of methyl acrylate to give G = 0.5 (electrophilic, carbomethoxy surface). This is followed by amidation to return to a nucleophilic surface at G = 1.0. As a result of this reiterative branch cell assembly, it is apparent that these constructions follow systematic dendritic branching rules, with radial symmetry giving a well-defined three-dimensional geometry to the final dendritic product. In general, the placement of reactive functionalities on the exterior surface of the dendrimers allows introduction of a wide variety of terminal moieties. In alternate synthetic approaches, spacer groups have been deliberately introduced to relieve the steric hindrance in order to facilitate construction of the next generation. This may provide the possibility of enhancing interior cargo spaces for ‘guest–host’ type chemistry.
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da Silva, Joaquim G. G. Esteves, Manuel Algarra, and Bruno B. "Synthesis and Analytical Applications of Quantum Dots Coated with Different Generations of DAB Dendrimers." In Advances in Nanocomposites - Synthesis, Characterization and Industrial Applications. InTech, 2011. http://dx.doi.org/10.5772/13856.
Full textConference papers on the topic "GENERATION DENDRIMERS"
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Seniutinas, G., R. Tomasiunas, R. Czaplicki, B. Sahraoui, and V. Kampars. "Third harmonic generation via dendrimers of four generations." In 2009 3rd ICTON Mediterranean Winter Conference (ICTON-MW 2009). IEEE, 2009. http://dx.doi.org/10.1109/ictonmw.2009.5385570.
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Burn, Paul L., Mounir Halim, Jonathan N. G. Pillow, and Ifor D. W. Samuel. "Effect of generation on the electronic properties of light-emitting dendrimers." In SPIE's International Symposium on Optical Science, Engineering, and Instrumentation, edited by Zakya H. Kafafi. SPIE, 1999. http://dx.doi.org/10.1117/12.372741.
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Betancourt, Beatriz A. Pazmiño, and Jack F. Douglas. "Evolution of dendrimer conformational structure with generation number." In VIII INTERNATIONAL CONFERENCE ON “TIMES OF POLYMERS AND COMPOSITES”: From Aerospace to Nanotechnology. Author(s), 2016. http://dx.doi.org/10.1063/1.4949652.
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Ristić, Sanja, Jovan Mijović, Alberto D’Amore, Domenico Acierno, and Luigi Grassia. "DIELECTRIC PROPERTIES OF GENERATION 3 PAMAM DENDRIMER NANOCOMPOSITES." In IV INTERNATIONAL CONFERENCE TIMES OF POLYMERS (TOP) AND COMPOSITES. AIP, 2008. http://dx.doi.org/10.1063/1.2989077.
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"PAMAM Dendrimers as anti-HER2 Positive Breast Cancer Treatment." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0176.
Full textAbstract:
Background: Poly (amidoamine) dendrimers (PAMAMs) are widely used in drug delivery systems and gene transfection as drug carriers. They also exert several biological effects like modulating gene expression, particularly EGFR (ErbB1) signaling pathway, which raises the question of whether these polymers can also inhibit the phosphorylation of HER2 (ErbB2) in breast cancer. However, this area hasn’t been investigated before. Methods: In this study, we evaluated the anticancer effects of different generations and surface chemistries of PAMAMs on HER2 positive breast cancer cells (SkBr3 and ZR-75 cell lines). Cell viability and morphological changes were evaluated upon treatment with PAMAMs. In addition, their effect on colony formation in soft agar was assessed. Additionally, western blot was performed to understand the underlying mechanisms of action. Results: PAMAMs anticancer effects were found to follow a specific trend, as they were more significant in cationic polymers and in higher generations. Cationic PAMAMs reduced cell viability of HER2 positive breast cancer cells up to 5.1% in SkBr3 and to 28% in ZR75 (p<0.001), in a dose and time-dependent manner. Cationic polymers also resulted in changing the morphology in the examined cell lines, as well as inhibiting colony formation in soft agar compared to controls (p<0.001). The mechanism of action was found to be mediated by inhibiting the phosphorylation of erbB2 and JNK1/2/3. Conclusion: These anticancer effects of PAMAM dendrimers make them promising molecules, which can add benefit to current anti-HER2 treatments and be employed successfully in different biomedical applications.
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Prakash, Shaurya, Timothy M. Long, Jonathan Wan, Jeffrey S. Moore, and Mark A. Shannon. "Electroosmotic Flow in “Click” Surface Modified Microfluidic Channels." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96153.
Full textAbstract:
A rapid, facile, and modular surface modification scheme for the covalent attachment of pre-formed polymer moieties to self-assembled monolayers via ‘click’ chemistry within glass microfluidic channels (3 cm long, 110 μm wide and 15 μm deep) is described. The effect that different moieties have on the electroosmotic flow (EOF) within the microchannels is evaluated. The application of linear polymers such as poly(ethylene glycol) (PEG) generates hydrophilic surfaces that reduce the analyte-wall interactions, thereby increasing separation efficiency and improving resolution, especially in bio-separations. Dendritic polymers such as poly(amido amine) (PAMAM) on channel walls can provide high-surface area structures with tunable surface charge depending on the generation of the dendrimer coating. Modified surfaces are characterized by X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared-Attenuated Total Reflection spectroscopy (FTIR-ATR), and contact angle measurements. EOF measurements in modified and unmodified channels provide information about wall-analyte interactions. A PAMAM dendrimer coated channel presents an amine terminated surface with a positive charge in contrast to a negatively charged bare-glass surface. Use of surface coatings can lead to an increase of the EOF by 15% as is the case for an azide terminated surface or reverse the direction of EOF as is the case for the PAMAM coatings by changing the surface charge polarity.
Reports on the topic "GENERATION DENDRIMERS"
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Uppuluri, Srinivas, Petar R. Dvornic, June W. Klimash, Peter I. Carver, and Nora C. Tan. The Properties of Dendritic Polymers I: Generation 5 Poly(amidoamine) Dendrimers. Fort Belvoir, VA: Defense Technical Information Center, May 1998. http://dx.doi.org/10.21236/ada346880.
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Uppuluri, Srinivas, Petar R. Dvornic, Nora C. Beck Tan, and Gary Hagnauer. The Properties of Dendritic Polymers 2: Generation Dependence of the Physical Properties of Poly(amidoamine) Dendrimers. Fort Belvoir, VA: Defense Technical Information Center, January 1999. http://dx.doi.org/10.21236/ada359423.
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