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sciforum-001970
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Investigation the Effect of Polyaniline Modification of Carbon Nanotubes/Nickel Foam Based Electrodes Using in Supercapacitors
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N/A
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supercapacitiveperformances of carbon nanotube (CNT) based electrodes, before and afterelectrochemical deposition of polyaniline (PANI) were compared. The PANImodified CNT/Nickel foam based electrodes were compared with the bare carbonnanotubes/Ni foam based electrodes. The modified electrode prepared by coatingCNT based electrodes which were directly grown on a Ni-foam framework by aChemical Vapor deposition (CVD) technique. The PANI modified electrode exhibitsbetter capacitive performance and lower internal resistance than the bareCNT/Ni foam electrode. The specific capacitance of this CNT/PANI based electrodeis 70 F/g which is 37 percent higher than the value of the CNT/Nifoam electrode before deposition of PANI. This work proposes that modificationCNTs with PANI is a simple, effective and economical approach for preparing asuitable supercapacitor electrode which possess enhanced capacitance and rateperformance.
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sciforum-002232
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Synthesis and Characterization of Tin(II) 5,10,15,20-Tetrakis(4-Phenylbenzoate)Porphyrin and Tin(II) 5,10,15,20-Tetrakis(4-[1,1ʹ-Biphenyl]-4ylbenzoate)Porphyrin
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N/A
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Porphyrins are stable molecules with a macrocyclic conjugated system and often peripheral substituents. Herein we reported the synthesis and characterization of a new type of metalloporphyrin. SnTCPP was synthesized and dissolved in THF, and then thionylchloride was slowly added into solution to start reaction under stirring at 70 ⁰C for 2 h. The excess thionylcholoride must be removed. Then phenol or 1, 1ʹ-biphenyl – 4– ol was added to the solution and the mixture was stirred and refluxed for 8 h. The corresponding products (5,10,15,20-tetrakis(4-phenylbenzoate)porphyrin and 5,10,15,20-tetrakis(4-[1,1ʹ-biphenyl]-4yl benzoate)porphyrin) were obtained. We identified the products by FT-IR and UV-Vis techniques. We investigated the effect of functional groups (phenol and 1, 1ʹ-biphenyl – 4– ol) in photocatalytic degradation of methylene blue under visible light irradiation in the same conditions.
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sciforum-000668
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Theoretical Study of the Solvent Effect on the properties of Indole‑Cation‑Anion Complexes
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N/A
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The properties of ternary indole-cation-anion (IMX) complexes are theoretically studied as simplified models of real systems in which some of the fragments used are parts of bigger and complicated structures, like proteins. The electro-neutrality of real systems and the presence of ions of both charges interacting simultaneously with aromatic residues in the proteins modeled justify the move from cation-π or anion-π (non-bonding interactions analyzed by our group in previous studies) to cation-π-anion complexes. With the intention of approaching more the model to reality, the solvent was also included in the study: aqueous solvent was represented by a combination of PCM + explicit addition of one water molecule to some IMX complexes. As model systems for this study the complexes with indole and the following cations and anions were selected: M = Na+, NH4+; X = HCOO–, NO3– or Cl–. The effect of the solvent was studied not only on the energy but as well on some structural parameters like the proton transfer from the ammonium cation to the basic anion and the cation-anion separation. The results indicate that the PCM method alone properly reproduces the main energetic and geometrical changes, even at quantitative level, but the explicit hydration allows refining the solvent effect and detecting cases that do not follow the general trend.
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sciforum-001840
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Syntheses and Reactions of 5-Alkyl- and 5-Aryl-11b-Methyl-1,2,3,11b-Tetrahydro-Pyrido[3,2,1-jk]carbazoles Having a Strychnos Alkaloids Partial Structure
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Arylhydrazines 1 react with 2-methylcyclohexanone 2 via Fischer indole synthesis to 4a-methyl-2,3,3,4a-tetrahydro-1H-carbazoles 3, which cyclize with 2-substituted malonates 5 to give 5-aryl- and 5-alkylsubstituted 4-hydroxy-11b-methyl-1,2,3,11b-tetrahydro-6H-pyrido[3,2,1-jk]carbazol-6-ones 6. Pyridocarbazoles 6 can be shown to give a series of reactions, such as electrophilic halogenation to 5-chloro-pyridocarbazole-4,6-dione 9, and nucleophilic halogenation to 4-chloro-pyridocarbazol-6-one 11. 4-Azido-5-phenylpyridocarbazol-6-one 13 cyclizes under thermolysis to the indolo derivative 14. This reaction was studied by differential scanning calorimetry (DSC).
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sciforum-002988
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Synthesis and Antifungal Activity of Perylene Bisimide Derivatives
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N/A
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The frequency of opportunistic fungal infection has increased drastically, mainly in patients who are immunocompromised due to organ transplant, leukaemia or HIV infection. Candida albicans is responsible for most infections caused by fungi; however, the incidence of non-albicans species that are resistant, less susceptible or potentially resistant to currently antifungal drugs, such as Candida parapsilosis, Candida krusei, Candida tropicalis, appears to be increasing. Filamentous fungi infections are less frequent than Candida species infection, but are associated with high mortality rates. Despite the addition of new classes of antifungals, the number of currently available drugs for the treatment of fungal infections remains limited.Perylene derivatives are compounds used in a variety of industrial applications for decades, especially in the dye-sensitized solar cells, organic light-emitting diodes, and organic thin film transistors. Moreover, these compounds have shown some anticancer, antiviral, antidepressant, and antibacterial activities.In this study, we have synthesized several perylene bisimide derivatives and evaluated the antifungal activity against human pathogenic yeasts (Candida spp.) and filamentous fungi (Aspergillus spp., Fusarium spp., and Trichophyton spp.).Three compounds (2-4) from the nine compounds tested presented relevant activity. Compound 2 was active against Candida albicans, C. parapsilosis and C. tropicalis with minimum inhibitory concentrations (MIC90) values of 25.0, 22.0 and 14.0 µg/mL, respectively. Similarly, compound 3 was active against these three yeasts with MIC90 values of 7.0, 5.0 and 6.0 µg/mL, respectively, while compound 4 showed a MIC90 value below 3,1 µg/mL, being this compound the most potent. These three compopunds also showed activity against filamentous fungi, F. oxysporum, T. rubrum and T. mentagrophytes at a concentration of 50 µg/mL. The resultant data indicates that perylene bisimides (2-4) display wide spectrum and relevant antifungal activity. Compound 4 represents a new scaffold for the development of antifungal agents and warrant further structure activity relationship studies.
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