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Virgil Percec - One of the best experts on this subject based on the ideXlab platform.
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functionally terminated poly methyl acrylate by set lrp initiated with chbr3 and chi3
Journal of Polymer Science Part A, 2008Co-Authors: Gerard Lligadas, Janine S Ladislaw, Tamaz Guliashvili, Virgil PercecAbstract:The single-electron transfer living radical polymerization (SET-LRP) of methyl acrylate initiated with bromoform (CHBr 3 ) and Iodoform (CHI 3 ) and catalyzed by Cu(0)/Me 6 -TREN in DMSO at 25 °C provides a reliable method to prepare poly (methyl acrylate) (PMA) with active chain ends and controlled structure that can undergo subsequent functionalization to provide strategies for the synthesis of different block copolymers and other complex architectures. A detailed kinetic and structural analysis was used to assess the scope and the limitations of CHBr 3 and CHI 3 as initiators under SET-LRP conditions.
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ultrafast single electron transfer degenerative chain transfer mediated living radical polymerization of acrylates initiated with Iodoform in water at room temperature and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Luis A Hinojosafalcon, Tamaz GuliashviliAbstract:Sodium dithionite in the presence of NaHCO3 in water acts as a single- electron-transfer agent and facilitates the single-electron-transfer/degenerative-chain- transfer mediated living radical polymerization (SET-DTLRP) of acrylates initiated with Iodoform at room temperature. The resulting ,-di(iodo)polyacrylates can be used as macroinitiators for the SET-DTLRP of other acrylates. Ultrahigh-molar-mass poly- (tert-butyl acrylate) can be synthesized via the SET-DTLRP of tert-butyl acrylate and has a very low weight-average molecular weight/number-average molecular weight ratio of 1.15. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2178 -2184, 2005
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single electron transfer degenerative chain transfer mediated living radical polymerization set dtlrp of vinyl chloride initiated with methylene iodide and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Jorge F J CoelhoAbstract:Single electron transfer–degenerative chain transfer mediated living radical polymerization (SET–DTLRP) of vinyl chloride (VC) initiated with methylene iodide (CH2I2) and catalyzed by sodium dithionite (Na2S2O4) in water at 35 °C produces a telechelic poly(vinyl chloride) (LRP–PVC) with two different active chain ends: ICH2(CH2CHCl)n-1CH2CHClI, and 2.0 functionality. The reactivity and initiator efficiency of CH2I2 in SET–DTLRP of VC was lower than those of Iodoform. A possible mechanism for the CH2I2-initiated SET–DTLRP of VC was suggested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 773–778, 2005
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aqueous room temperature metal catalyzed living radical polymerization of vinyl chloride
Journal of the American Chemical Society, 2002Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Michael J Monteiro, Bogdan Barboiu, Oliver Weichold, A D Asandei, Catherine M MitchellAbstract:This paper describes the room-temperature living radical polymerization (LRP) of vinyl chloride in H2O/THF in the presence of Cu0 or CuI salts as catalysts, tren or PEI as ligands, and Iodoform as initiator. The disproportionation reaction 2CuI + L → Cu0 + CuII(L) is the crucial step, as it continuously provides the active species for both the initiation (Cu0) and the reversible termination step (CuII). Mn was found to increase linearly with conversion and is in good agreement with Mth, with the Mw/Mn being approximately 1.5.
Anatoliy V Popov - One of the best experts on this subject based on the ideXlab platform.
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ultrafast single electron transfer degenerative chain transfer mediated living radical polymerization of acrylates initiated with Iodoform in water at room temperature and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Luis A Hinojosafalcon, Tamaz GuliashviliAbstract:Sodium dithionite in the presence of NaHCO3 in water acts as a single- electron-transfer agent and facilitates the single-electron-transfer/degenerative-chain- transfer mediated living radical polymerization (SET-DTLRP) of acrylates initiated with Iodoform at room temperature. The resulting ,-di(iodo)polyacrylates can be used as macroinitiators for the SET-DTLRP of other acrylates. Ultrahigh-molar-mass poly- (tert-butyl acrylate) can be synthesized via the SET-DTLRP of tert-butyl acrylate and has a very low weight-average molecular weight/number-average molecular weight ratio of 1.15. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2178 -2184, 2005
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single electron transfer degenerative chain transfer mediated living radical polymerization set dtlrp of vinyl chloride initiated with methylene iodide and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Jorge F J CoelhoAbstract:Single electron transfer–degenerative chain transfer mediated living radical polymerization (SET–DTLRP) of vinyl chloride (VC) initiated with methylene iodide (CH2I2) and catalyzed by sodium dithionite (Na2S2O4) in water at 35 °C produces a telechelic poly(vinyl chloride) (LRP–PVC) with two different active chain ends: ICH2(CH2CHCl)n-1CH2CHClI, and 2.0 functionality. The reactivity and initiator efficiency of CH2I2 in SET–DTLRP of VC was lower than those of Iodoform. A possible mechanism for the CH2I2-initiated SET–DTLRP of VC was suggested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 773–778, 2005
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aqueous room temperature metal catalyzed living radical polymerization of vinyl chloride
Journal of the American Chemical Society, 2002Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Michael J Monteiro, Bogdan Barboiu, Oliver Weichold, A D Asandei, Catherine M MitchellAbstract:This paper describes the room-temperature living radical polymerization (LRP) of vinyl chloride in H2O/THF in the presence of Cu0 or CuI salts as catalysts, tren or PEI as ligands, and Iodoform as initiator. The disproportionation reaction 2CuI + L → Cu0 + CuII(L) is the crucial step, as it continuously provides the active species for both the initiation (Cu0) and the reversible termination step (CuII). Mn was found to increase linearly with conversion and is in good agreement with Mth, with the Mw/Mn being approximately 1.5.
Ernesto Ramirezcastillo - One of the best experts on this subject based on the ideXlab platform.
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ultrafast single electron transfer degenerative chain transfer mediated living radical polymerization of acrylates initiated with Iodoform in water at room temperature and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Luis A Hinojosafalcon, Tamaz GuliashviliAbstract:Sodium dithionite in the presence of NaHCO3 in water acts as a single- electron-transfer agent and facilitates the single-electron-transfer/degenerative-chain- transfer mediated living radical polymerization (SET-DTLRP) of acrylates initiated with Iodoform at room temperature. The resulting ,-di(iodo)polyacrylates can be used as macroinitiators for the SET-DTLRP of other acrylates. Ultrahigh-molar-mass poly- (tert-butyl acrylate) can be synthesized via the SET-DTLRP of tert-butyl acrylate and has a very low weight-average molecular weight/number-average molecular weight ratio of 1.15. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2178 -2184, 2005
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single electron transfer degenerative chain transfer mediated living radical polymerization set dtlrp of vinyl chloride initiated with methylene iodide and catalyzed by sodium dithionite
Journal of Polymer Science Part A, 2005Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Jorge F J CoelhoAbstract:Single electron transfer–degenerative chain transfer mediated living radical polymerization (SET–DTLRP) of vinyl chloride (VC) initiated with methylene iodide (CH2I2) and catalyzed by sodium dithionite (Na2S2O4) in water at 35 °C produces a telechelic poly(vinyl chloride) (LRP–PVC) with two different active chain ends: ICH2(CH2CHCl)n-1CH2CHClI, and 2.0 functionality. The reactivity and initiator efficiency of CH2I2 in SET–DTLRP of VC was lower than those of Iodoform. A possible mechanism for the CH2I2-initiated SET–DTLRP of VC was suggested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 773–778, 2005
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aqueous room temperature metal catalyzed living radical polymerization of vinyl chloride
Journal of the American Chemical Society, 2002Co-Authors: Virgil Percec, Anatoliy V Popov, Ernesto Ramirezcastillo, Michael J Monteiro, Bogdan Barboiu, Oliver Weichold, A D Asandei, Catherine M MitchellAbstract:This paper describes the room-temperature living radical polymerization (LRP) of vinyl chloride in H2O/THF in the presence of Cu0 or CuI salts as catalysts, tren or PEI as ligands, and Iodoform as initiator. The disproportionation reaction 2CuI + L → Cu0 + CuII(L) is the crucial step, as it continuously provides the active species for both the initiation (Cu0) and the reversible termination step (CuII). Mn was found to increase linearly with conversion and is in good agreement with Mth, with the Mw/Mn being approximately 1.5.
Vahid Rakhshan - One of the best experts on this subject based on the ideXlab platform.
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volumetric assessment of root canal obturation using 3 nano chitosan versus zinc oxide eugenol zoe and Iodoform calcium hydroxide metapex in primary root canals shaped with rotary versus manual methods a preliminary in vitro spiral ct study
Frontiers in Dentistry, 2019Co-Authors: Elahe Babashahi, Maryam Mohmadi Kartalaie, Leila Basir, Vahid RakhshanAbstract:Objectives In this study, chitosan was introduced and used as a substitute for pulpectomy obturation against conventional materials: zinc oxide eugenol (ZOE) and Iodoform-calcium hydroxide (Ca(OH)2). Efficacies of rotary versus manual instrumentations were also compared. Materials and Methods This preliminary study was performed on 152 intact nonresorbed root canals of primary molars divided into rotary (n=78) versus hand-instrumentation (n=74) and into ZOE (n=53), Iodoform-Ca(OH)2 (n=50), and 3% nano-chitosan (n=49). Canals were cleaned/shaped using hand or rotary files. Canal spaces were measured using spiral computed tomography and obturated using the three materials. The percentages of obturation volume (POV) were estimated. Rotary and manual instrumentations were compared in terms of canal spaces before and after obturation. Three obturation materials were also compared regarding canal spaces after obturation (α=0.05). Results Average POVs of materials were 96.54% (ZOE), 97.87% (Metapex), and 74.74% (nano-chitosan; P=0.000). POV of chitosan differed from the other two (P<0.001) but the other two were similar (P=0.896). Average POVs were 91.46% (manual) and 88.51% (rotary); the difference was not significant (P=0.322). Preobturation spaces of canals for different methods were 3.89 mm 3 (manual) and 3.26 mm 3 (rotary); the difference was significant (P=0.013). Two-way ANCOVA showed a significant effect of materials (P<0.001) but not root length (P=0.585) or shaping methods (P=0.362) on POVs. Conclusion Nano-chitosan showed a considerable success rate but it still needs reformulation as it was weaker than the extremely successful commercial competitors. Rotary instrumentation can provide results similar to hand-filing in terms of POV although it might yield smaller canals.
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Volumetric Assessment of root canal obturation using 3% nano-chitosan versus zinc oxide eugenol (ZOE) and Iodoform-calcium hydroxide (Metapex), in primary root canals shaped with rotary versus manual methods: A preliminary in-vitro spiral CT study
Tehran University of Medical Sciences, 2019Co-Authors: Elahe Babashahi, Maryam Mohmadi Kartalaie, Leila Basir, Vahid RakhshanAbstract:Background: Currently, cytotoxic materials are used for pulpectomy obturation in primary teeth (mostly ZOE or Iodoform-Ca(OH)2 compounds). This study compared the volumetric quality of a new biocompatible/antimicrobial agent (nano-chitosan) against conventional obturation materials. It also compared rotary and manual systems. Methods: This preliminary in-vitro study was performed on 152 intact non-resorbed root canals of primary molars, divided into [rotary (n=78) versus hand-instrumentation (n=74)], and also into [ZOE (n=53), an Iodoform-Ca(OH)2 (n=50), and 3% nano-chitosan (n=49)]. Canals were cleaned/shaped using hand- or rotary-files. Canal spaces were measured using spiral CT. Canals were then obturated using the three materials. The percentages of obturation volume (POV) were estimated for the materials. Canal spaces both before obturation and after it were compared statistically between two filing systems, and between 3 obturation materials (α=0.05). Results: Average POVs of materials were 96.54% (ZOE), 97.87% (Metapex), and 74.74% (nano-chitosan, ANOVA P=0.000). POV of chitosan differed from the other two (Tukey P=0.000), but the other two were similar (P=0.896). Average POVs were 91.46% (manual) and 88.51% (rotary, t-test P=0.322). Pre-obturation spaces of canals for different methods were 3.89 mm3 (manual) and 3.26 mm3 (rotary, t-test P=0.013). Two-way ANCOVA showed a significant effect of materials (P=0.000) but not root length (P=0.585) or shaping methods (P=0.362) on POVs. Conclusions: The nano-chitosan showed a considerable success, but it still needs reformulation as it was weaker than the extremely successful commercial competitors. Rotary instrumentation can provide results similar to hand-filing in terms of POV, although they might yield smaller canals
Hideo Togo - One of the best experts on this subject based on the ideXlab platform.
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direct transformation of ethylarenes into primary aromatic amides with n bromosuccinimide and i2 aqueous nh3
Organic Letters, 2016Co-Authors: Shohei Shimokawa, Yuhsuke Kawagoe, Katsuhiko Moriyama, Hideo TogoAbstract:A variety of ethylarenes were converted into the corresponding primary aromatic amides in good yields via treatment with N-bromosuccinimide in the presence of a catalytic amount of 2,2′-azobis(isobutyronitrile) in a mixture of ethyl acetate and water, acetonitrile and water, or chloroform and water, followed by reaction with molecular iodine and aq NH3 in one pot. It was found that aryl α-bromomethyl ketones and/or aryl methyl ketones were formed at the first reaction step and their Iodoform-type reaction occurred at the second reaction step to provide primary aromatic amides. The present reaction is a useful and practical transition-metal-free method for the preparation of primary aromatic amides from ethylarenes.
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Direct Transformation of Ethylarenes into Primary Aromatic Amides with N‑Bromosuccinimide and I2–Aqueous NH3
2016Co-Authors: Shohei Shimokawa, Yuhsuke Kawagoe, Katsuhiko Moriyama, Hideo TogoAbstract:A variety of ethylarenes were converted into the corresponding primary aromatic amides in good yields via treatment with N-bromosuccinimide in the presence of a catalytic amount of 2,2′-azobis(isobutyronitrile) in a mixture of ethyl acetate and water, acetonitrile and water, or chloroform and water, followed by reaction with molecular iodine and aq NH3 in one pot. It was found that aryl α-bromomethyl ketones and/or aryl methyl ketones were formed at the first reaction step and their Iodoform-type reaction occurred at the second reaction step to provide primary aromatic amides. The present reaction is a useful and practical transition-metal-free method for the preparation of primary aromatic amides from ethylarenes
