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Timothy E. Long - One of the best experts on this subject based on the ideXlab platform.
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Phosphonium-containing diblock copolymers from living anionic polymerization of 4-diphenylphosphino styrene
Chemical Communications, 2016Co-Authors: Alison R. Schultz, Chainika Jangu, Gregory B. Fahs, Mingtao Chen, Robert B. Moore, Timothy E. LongAbstract:Living anionic polymerization of 4-diphenylphosphino styrene (DPPS) achieved well-defined homopolymers, poly(DPPS-b-S) styrenic block copolymers, and poly(I-b-DPPS) diene-based diblock copolymers with predictable molecular weights and narrow polydispersities. In situ FTIR spectroscopy monitored the anionic polymerization of DPPS and tracked monomer consumption for kinetic analysis. Post-alkylation enabled controlled placement of Phosphonium functionality in poly(I-b-DPPS) diblock copolymers, producing well-defined Phosphonium-containing block copolymers with low degrees of compositional heterogeneity. Incorporating Phosphonium charge disrupted the lamellar bulk morphology of the neutral diblock precursor and provided morphologies with interdigitated packing of alkyl chains on the Phosphonium cation.
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solution properties and electrospinning of Phosphonium gemini surfactants
Soft Matter, 2014Co-Authors: Sean T Hemp, Robert B. Moore, Amanda G Hudson, Michael H Allen, Sandeep S Pole, Timothy E. LongAbstract:Bis(diphenylphosphino)alkanes quantitatively react with excess 1-bromododecane to prepare novel Phosphonium gemini surfactants with spacer lengths ranging from 2 to 4 methylenes (12-2/3/4-12P). DodecyltriphenylPhosphonium bromide (DTPP), a monomeric surfactant analog, was readily water soluble, however, in sharp contrast, Phosphonium gemini surfactants were poorly soluble in water due to two hydrophobic tails and relatively hydrophobic cationic head groups containing phenyl substituents. Isothermal titration calorimetry did not reveal a measurable critical micelle concentration for the 12-2-12P Phosphonium gemini surfactant in water at 25 °C. Subsequent studies in 50/50 v/v water–methanol at 25 °C showed a CMC of 1.0 mM for 12-2-12P. All Phosphonium gemini surfactants effectively complexed nucleic acids, but failed to deliver nucleic acids in vitro to HeLa cells. The solution behavior of Phosphonium gemini surfactants was investigated in chloroform, which is an organic solvent where reverse micellar structures are favored. Solution rheology in chloroform explored the solution behavior of the Phosphonium gemini surfactants compared to DTPP. The 12-2-12P and 12-3-12P gemini surfactants were successfully electrospun from chloroform to generate uniform fibers while 12-4-12P gemini surfactant and DTPP only electrosprayed to form droplets.
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Phosphonium ionenes from well defined step growth polymerization thermal and melt rheological properties
Polymer Chemistry, 2013Co-Authors: Sean T Hemp, Musan Zhang, Mana Tamami, Timothy E. LongAbstract:Step-growth polymerization of ditertiary phosphines with dibromoalkanes enabled the synthesis of novel Phosphonium ionenes. In situ FTIR spectroscopy monitored the increase in absorbance as a function of time at 1116 cm−1, which corresponded to the polymeric P+–Ph stretch. Aqueous size-exclusion chromatography (SEC) provided absolute molecular weights and confirmed expected molecular weight growth for difunctional, step-growth polymerization. Phosphonium ionenes exhibited improved thermal and base stability compared to ammonium ionenes, which was attributed to the propensity of the ammonium cation towards Hofmann elimination. Melt rheology examined Phosphonium ionene viscous flow and the influence of charge density on melt viscosity as a function of shear rate and temperature. Time–temperature superposition (TTS) resulted in both master curves and pseudomaster curves depending on Phosphonium ionene composition. Two primary relaxations occurred: (1) onset of long-range segmental motion at Tg, and (2) relaxation attributed to electrostatic interactions. Higher charge densities shifted these two relaxations to longer time scales and increased flow activation energies. Phosphonium ionenes also readily bound pDNA effectively (± ratios of 1), and base stability suggested applications in energy generation.
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Phosphonium-Containing ABA Triblock Copolymers: Controlled Free Radical Polymerization of Phosphonium Ionic Liquids
Macromolecules, 2011Co-Authors: Shijing Cheng, Robert B. Moore, Frederick L. Beyer, Brian D. Mather, Timothy E. LongAbstract:Phosphonium ion-containing acrylate triblock (ABA) copolymers were synthesized using nitroxide mediated radical polymerization. The polymerization of styrenic Phosphonium-containing ionic liquid monomers using a difunctional alkoxyamine initiator, DEPN2, afforded an ABA triblock copolymer with an n-butyl acrylate soft center block (DP ∼ 400) and symmetric Phosphonium-containing external reinforcing blocks (DP < 30). Two Phosphonium monomers with different alkyl substituent lengths enabled an investigation of the effects of ionic aggregation of Phosphonium cations on the physical properties of ABA block copolymer ionomers. Subsequently, the thermomechanical properties and morphologies of these materials were compared to a noncharged triblock copolymer analogue with neutral polystyrene external blocks. Shortening the alkyl substituents on the Phosphonium cation enhanced the hydrophilicity of tributyl-4-vinylbenzyl Phosphonium chloride (BPCl) relative to trioctyl-4-vinylbenzyl Phosphonium chloride (OPCl). In...
Katsuhiko Tsunashima - One of the best experts on this subject based on the ideXlab platform.
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physical and electrochemical characterization of ionic liquids based on quaternary Phosphonium cations containing a carbon carbon double bond
Electrochimica Acta, 2011Co-Authors: Katsuhiko Tsunashima, Masashi SugiyaAbstract:Abstract Physical and electrochemical characterizations of novel two ionic liquids based on quaternary Phosphonium cations containing an unsaturated carbon–carbon bond (triethyl(4-pentenyl)Phosphonium and allyltributylPhosphonium cations) are presented in this report. It was found that both unsaturated Phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the unsaturated Phosphonium ionic liquids showed higher thermal stability than those of the corresponding saturated Phosphonium ILs. The unsaturated Phosphonium ionic liquids also exhibited relatively low viscosity and high conductivities when compared to those of the corresponding saturated Phosphonium ionic liquids. These results indicate an improving effect of introducing a carbon–carbon double bond into the Phosphonium cations on both the thermal stability and the transport property. The voltammetric measurements suggested that the triethyl(4-pentenyl)Phosphonium-based ionic liquid showed a high cathodic stability, enabling the deposition and dissolution of metallic lithium in the Phosphonium ionic liquid system.
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low viscous and highly conductive Phosphonium ionic liquids based on bis fluorosulfonyl amide anion as potential electrolytes
Electrochemistry Communications, 2011Co-Authors: Katsuhiko Tsunashima, Masashi Sugiya, Atsuko Kawabata, Masahiko Matsumiya, Shun Kodama, Ryuichi Enomoto, Yoshihito KunugiAbstract:Abstract The physical and electrochemical properties of room-temperature ionic liquids based on quaternary Phosphonium cations together with a bis(fluorosulfonyl)amide anion are presented in this report. The bis(fluorosulfonyl)amide-based Phosphonium ionic liquids were relatively low-melting, low viscous and highly conductive when compared to those of the corresponding bis(trifluoromethylsulfonyl)amide-based ionic liquids. Particularly, the ionic liquids containing a methoxy group in the Phosphonium cations indicated very low viscosities and high conductivities. The FSA-based Phosphonium RTILs were thermally stable up to nearly 300 °C. The voltammetric analysis suggested that the bis(fluorosulfonyl)amide-based Phosphonium ionic liquids showed high electrochemical stability similar to the corresponding bis(trifluoromethylsulfonyl)amide-based ionic liquids.
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Effect of Quaternary Phosphonium Salts in Organic Electrolyte for Lithium Secondary Batteries
Electrochemistry, 2011Co-Authors: Katsuhiko Tsunashima, Fumihiro Yonekawa, Masahiro Kikuchi, Masashi SugiyaAbstract:Additive behaviors of several bis (trifluoromethylsulfonyl) amide-based Phosphonium salts in an organic electrolyte used for lithium secondary batteries are reported. Electrolytic properties of a lithium hexafluorophosphatebased organic electrolyte mixed with the Phosphonium salts were examined. It was found that the mixed electrolytes containing the Phosphonium salts showed lower conductivities and higher viscosities than the organic electrolyte. However, in the case of the mixed Phosphonium electrolytes based on asymmetrical cations, the charge-discharge cyclabilities of the lithium battery cells were superior to that of the cell containing the organic electrolyte. Furthermore, the thermal stability of LiCoO2 cathodes charged in the mixed Phosphonium electrolytes was considerably improved. These results suggest that the Phosphonium salts are regarded as effective electrolyte additives for lithium secondary batteries.
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Thermal and transport properties of ionic liquids based on benzyl-substituted Phosphonium cations.
The journal of physical chemistry. B, 2009Co-Authors: Katsuhiko Tsunashima, Masashi Sugiya, Shun Kodama, Eiko Niwa, Yasushi OnoAbstract:The physicochemical properties of two novel ionic liquids based on benzyltriethylPhosphonium and benzyltributylPhosphonium cations are described in this report. It was found that both benzyl-substituted Phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the benzyl-substituted Phosphonium ionic liquids showed higher thermal stability than those of not only the alkyl-substituted Phosphonium ILs but also the corresponding benzyl-substituted ammonium compounds. The benzyl-substituted Phosphonium ionic liquids also exhibited relatively high conductivities when compared to those of the corresponding ammonium compounds. These results indicate an improving effect of introducing a benzyl group into the Phosphonium cations on both the thermal stability and the conductivity.
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physical and electrochemical properties of low viscosity Phosphonium ionic liquids as potential electrolytes
Electrochemistry Communications, 2007Co-Authors: Katsuhiko Tsunashima, Masashi SugiyaAbstract:Abstract A new group of room temperature ionic liquids based on triethylalkylPhosphonium cations together with a bis(trifluoromethylsulfonyl)imide anion as a novel electrolyte is presented in this report. It was found that Phosphonium ionic liquids showed lower viscosities and higher conductivities than those of the corresponding ammonium ionic liquids. Particularly, Phosphonium ionic liquids containing a methoxy group, triethyl(methoxymethyl)Phosphonium bis(trifluoromethylsulfonyl)imide and triethyl(2-methoxyethyl)Phosphonium bis(trifluoromethylsulfonyl)imide, exhibited quite low viscosities (35 and 44 mPa s at 25 °C, respectively). Linear sweep voltammetry measured in neat Phosphonium ionic liquids at a glassy carbon electrode indicated wide potential windows (at least −3.0 to +2.3 V vs. Fc/Fc + ). Thermogravimetric analysis suggested that Phosphonium ionic liquids were thermally stable up to nearly 400 °C, showing slower gravimetric decreases at high temperature compared to those of the corresponding ammonium ionic liquids.
Masashi Sugiya - One of the best experts on this subject based on the ideXlab platform.
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physical and electrochemical characterization of ionic liquids based on quaternary Phosphonium cations containing a carbon carbon double bond
Electrochimica Acta, 2011Co-Authors: Katsuhiko Tsunashima, Masashi SugiyaAbstract:Abstract Physical and electrochemical characterizations of novel two ionic liquids based on quaternary Phosphonium cations containing an unsaturated carbon–carbon bond (triethyl(4-pentenyl)Phosphonium and allyltributylPhosphonium cations) are presented in this report. It was found that both unsaturated Phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the unsaturated Phosphonium ionic liquids showed higher thermal stability than those of the corresponding saturated Phosphonium ILs. The unsaturated Phosphonium ionic liquids also exhibited relatively low viscosity and high conductivities when compared to those of the corresponding saturated Phosphonium ionic liquids. These results indicate an improving effect of introducing a carbon–carbon double bond into the Phosphonium cations on both the thermal stability and the transport property. The voltammetric measurements suggested that the triethyl(4-pentenyl)Phosphonium-based ionic liquid showed a high cathodic stability, enabling the deposition and dissolution of metallic lithium in the Phosphonium ionic liquid system.
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low viscous and highly conductive Phosphonium ionic liquids based on bis fluorosulfonyl amide anion as potential electrolytes
Electrochemistry Communications, 2011Co-Authors: Katsuhiko Tsunashima, Masashi Sugiya, Atsuko Kawabata, Masahiko Matsumiya, Shun Kodama, Ryuichi Enomoto, Yoshihito KunugiAbstract:Abstract The physical and electrochemical properties of room-temperature ionic liquids based on quaternary Phosphonium cations together with a bis(fluorosulfonyl)amide anion are presented in this report. The bis(fluorosulfonyl)amide-based Phosphonium ionic liquids were relatively low-melting, low viscous and highly conductive when compared to those of the corresponding bis(trifluoromethylsulfonyl)amide-based ionic liquids. Particularly, the ionic liquids containing a methoxy group in the Phosphonium cations indicated very low viscosities and high conductivities. The FSA-based Phosphonium RTILs were thermally stable up to nearly 300 °C. The voltammetric analysis suggested that the bis(fluorosulfonyl)amide-based Phosphonium ionic liquids showed high electrochemical stability similar to the corresponding bis(trifluoromethylsulfonyl)amide-based ionic liquids.
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Effect of Quaternary Phosphonium Salts in Organic Electrolyte for Lithium Secondary Batteries
Electrochemistry, 2011Co-Authors: Katsuhiko Tsunashima, Fumihiro Yonekawa, Masahiro Kikuchi, Masashi SugiyaAbstract:Additive behaviors of several bis (trifluoromethylsulfonyl) amide-based Phosphonium salts in an organic electrolyte used for lithium secondary batteries are reported. Electrolytic properties of a lithium hexafluorophosphatebased organic electrolyte mixed with the Phosphonium salts were examined. It was found that the mixed electrolytes containing the Phosphonium salts showed lower conductivities and higher viscosities than the organic electrolyte. However, in the case of the mixed Phosphonium electrolytes based on asymmetrical cations, the charge-discharge cyclabilities of the lithium battery cells were superior to that of the cell containing the organic electrolyte. Furthermore, the thermal stability of LiCoO2 cathodes charged in the mixed Phosphonium electrolytes was considerably improved. These results suggest that the Phosphonium salts are regarded as effective electrolyte additives for lithium secondary batteries.
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Thermal and transport properties of ionic liquids based on benzyl-substituted Phosphonium cations.
The journal of physical chemistry. B, 2009Co-Authors: Katsuhiko Tsunashima, Masashi Sugiya, Shun Kodama, Eiko Niwa, Yasushi OnoAbstract:The physicochemical properties of two novel ionic liquids based on benzyltriethylPhosphonium and benzyltributylPhosphonium cations are described in this report. It was found that both benzyl-substituted Phosphonium cations gave low-melting salts in combination with a bis(trifluoromethylsulfonyl)amide anion. The thermogravimetric analysis suggested that the benzyl-substituted Phosphonium ionic liquids showed higher thermal stability than those of not only the alkyl-substituted Phosphonium ILs but also the corresponding benzyl-substituted ammonium compounds. The benzyl-substituted Phosphonium ionic liquids also exhibited relatively high conductivities when compared to those of the corresponding ammonium compounds. These results indicate an improving effect of introducing a benzyl group into the Phosphonium cations on both the thermal stability and the conductivity.
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physical and electrochemical properties of low viscosity Phosphonium ionic liquids as potential electrolytes
Electrochemistry Communications, 2007Co-Authors: Katsuhiko Tsunashima, Masashi SugiyaAbstract:Abstract A new group of room temperature ionic liquids based on triethylalkylPhosphonium cations together with a bis(trifluoromethylsulfonyl)imide anion as a novel electrolyte is presented in this report. It was found that Phosphonium ionic liquids showed lower viscosities and higher conductivities than those of the corresponding ammonium ionic liquids. Particularly, Phosphonium ionic liquids containing a methoxy group, triethyl(methoxymethyl)Phosphonium bis(trifluoromethylsulfonyl)imide and triethyl(2-methoxyethyl)Phosphonium bis(trifluoromethylsulfonyl)imide, exhibited quite low viscosities (35 and 44 mPa s at 25 °C, respectively). Linear sweep voltammetry measured in neat Phosphonium ionic liquids at a glassy carbon electrode indicated wide potential windows (at least −3.0 to +2.3 V vs. Fc/Fc + ). Thermogravimetric analysis suggested that Phosphonium ionic liquids were thermally stable up to nearly 400 °C, showing slower gravimetric decreases at high temperature compared to those of the corresponding ammonium ionic liquids.
Dandan Chen - One of the best experts on this subject based on the ideXlab platform.
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Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents
Journal of the American Chemical Society, 2019Co-Authors: Ting Shen, Dandan ChenAbstract:According to Huckel’s and Baird’s rules, cyclic conjugated species are aromatic either in the ground state or in the excited state only. Thus, species with aromaticity in both states (denoted as adaptive aromaticity) are particularly rare. Here we carry out density functional theory calculations on a series of osmapyridine and osmapyridinium complexes (96 species) and find that 2 of them display adaptive aromaticity, which was verified by various aromaticity indices including HOMA, ELFπ, MCI, ACIDπ plots, and the heat of hydrogenation. Further study reveals that two osmapyridiniums containing one or two Phosphonium substituents exhibit the character of the triplet ground state, which was supported by the high-level coupled cluster calculations. Our findings highlight the importance of a transition metal and Phosphoniums in achieving adaptive aromaticity and the triplet ground state and may aid the design of organometallics for photochemical and molecular magnetism applications.
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Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents
2019Co-Authors: Ting Shen, Dandan Chen, Lu Lin, Jun ZhuAbstract:According to Hückel’s and Baird’s rules, cyclic conjugated species are aromatic either in the ground state or in the excited state only. Thus, species with aromaticity in both states (denoted as adaptive aromaticity) are particularly rare. Here we carry out density functional theory calculations on a series of osmapyridine and osmapyridinium complexes (96 species) and find that 2 of them display adaptive aromaticity, which was verified by various aromaticity indices including HOMA, ELFπ, MCI, ACIDπ plots, and the heat of hydrogenation. Further study reveals that two osmapyridiniums containing one or two Phosphonium substituents exhibit the character of the triplet ground state, which was supported by the high-level coupled cluster calculations. Our findings highlight the importance of a transition metal and Phosphoniums in achieving adaptive aromaticity and the triplet ground state and may aid the design of organometallics for photochemical and molecular magnetism applications
Ting Shen - One of the best experts on this subject based on the ideXlab platform.
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Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents
Journal of the American Chemical Society, 2019Co-Authors: Ting Shen, Dandan ChenAbstract:According to Huckel’s and Baird’s rules, cyclic conjugated species are aromatic either in the ground state or in the excited state only. Thus, species with aromaticity in both states (denoted as adaptive aromaticity) are particularly rare. Here we carry out density functional theory calculations on a series of osmapyridine and osmapyridinium complexes (96 species) and find that 2 of them display adaptive aromaticity, which was verified by various aromaticity indices including HOMA, ELFπ, MCI, ACIDπ plots, and the heat of hydrogenation. Further study reveals that two osmapyridiniums containing one or two Phosphonium substituents exhibit the character of the triplet ground state, which was supported by the high-level coupled cluster calculations. Our findings highlight the importance of a transition metal and Phosphoniums in achieving adaptive aromaticity and the triplet ground state and may aid the design of organometallics for photochemical and molecular magnetism applications.
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Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents
2019Co-Authors: Ting Shen, Dandan Chen, Lu Lin, Jun ZhuAbstract:According to Hückel’s and Baird’s rules, cyclic conjugated species are aromatic either in the ground state or in the excited state only. Thus, species with aromaticity in both states (denoted as adaptive aromaticity) are particularly rare. Here we carry out density functional theory calculations on a series of osmapyridine and osmapyridinium complexes (96 species) and find that 2 of them display adaptive aromaticity, which was verified by various aromaticity indices including HOMA, ELFπ, MCI, ACIDπ plots, and the heat of hydrogenation. Further study reveals that two osmapyridiniums containing one or two Phosphonium substituents exhibit the character of the triplet ground state, which was supported by the high-level coupled cluster calculations. Our findings highlight the importance of a transition metal and Phosphoniums in achieving adaptive aromaticity and the triplet ground state and may aid the design of organometallics for photochemical and molecular magnetism applications
