scholarly journals Kinetic study of surfactant cobalt (III) complexes by [Fe(CN)6 4-]: Outer-Sphere Electron-Transfer in Ionic liquids and Liposome Vesicle

2020 ◽  
pp. 300-317
Author(s):  
Nagaraj Karuppiah ◽  
◽  
Pakkirisamy Pakkirisamy ◽  
Gunasekaran Gladwin ◽  
◽  
...  
Keyword(s):  
Phase Transition ◽  
Electron Transfer ◽  
Ionic Liquids ◽  
Transition Temperature ◽  
Transition State ◽  
Phase Transition Temperature ◽  
Outer Sphere ◽  
Complex Ions ◽  
Electron Transfer Mechanism ◽  
Outer Sphere Electron Transfer

UV-Vis., absorption spectroscopy are used to monitor the electron transfer reaction between the surfactant cobalt(III) complexes, cis-[Co(ip)2(C14H29NH2)2]3+, cis-[Co(dpq)2(C14H29NH2)2]3+ and cis-[Co(dpqc)2(C14H29NH2)2]3+ (ip = imidazo[4,5-f][1,10]phenanthroline, dpq = dipyrido[3,2-d:2’-3’-f]quinoxaline, dpqc = dipyrido[3,2-a:2’,4’-c](6,7,8,9-tetrahydro)phenazine, C14H29NH2=Tetradecylamine) and [Fe(CN)6]4- ion in liposome vesicles (DPPC) and ionic liquids ((BMIM)Br) were investigated at different temperatures under pseudo first order conditions using an excess of the reductant. The reactions were found to be second order and the electron transfer is postulated as outer-sphere. The rate constant for the electron transfer reactions were found to increase with increasing concentrations of ionic liquids. The effects of hydrophobicity of the long aliphatic double chains of these surfactant complex ions into liposome vesicles on these reactions have also been studied. Below the phase transition temperature of DPPC, the rate decreased with increasing concentration of DPPC, while above the phase transition temperature the rate increased with increasing concentration of DPPC. Kinetic data and activation parameters are interpreted in terms of an outer-sphere electron transfer mechanism. In all these media the S# values are found to be negative in direction in all the concentrations of complexes used indicative of more ordered structure of the transition state. This is consistent with a model in which the surfactant cobalt(III) complexes and Fe(CN)64- ions bind to the DPPC in the transition state. Thus, the results have been explained based on the self-aggregation, hydrophobic effect, and the reactants with opposite charge.

Influence of imidazolium based green solvents on volume phase transition temperature of crosslinked poly(N-isopropylacrylamide-co-acrylic acid) hydrogel

Soft Matter ◽  
2015 ◽  
Vol 11 (4) ◽  
pp. 785-792 ◽  
Author(s):  
Chi-Jung Chang ◽  
P. Madhusudhana Reddy ◽  
Shih-Rong Hsieh ◽  
Hsin-Chun Huang
Keyword(s):  
Phase Transition ◽  
Ionic Liquids ◽  
Transition Temperature ◽  
Acrylic Acid ◽  
Phase Transition Temperature ◽  
Polymeric Material ◽  
Volume Phase Transition ◽  
Green Solvents ◽  
Stimuli Responsive ◽  
Volume Phase

Ionic liquids, known as green solvents, can be used effectively to obtain the desired phase transition temperature for a given stimuli responsive polymeric material.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2020 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Adsorption Mechanism ◽  
Selective Adsorption ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; bdp<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including <sup>23</sup>Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O<sub>2</sub> uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate similar O<sub>2</sub> uptake behavior to that of A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> in an expanded-pore framework analogue and thereby gain additional insight into the O<sub>2</sub> adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2019 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Chemical Reduction ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that the chemically reduced metal–organic framework A<i><sub>x</sub></i>Fe<sub>2</sub>(BDP)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; BDP<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which features coordinatively-saturated iron centers, is capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. Through a combination of gas adsorption measurements, single-crystal X-ray diffraction, and numerous spectroscopic probes, including <sup>23</sup>Na solid-state NMR and X-ray photoelectron spectroscopy, we demonstrate that selective O<sub>2</sub> uptake likely occurs as a result of outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the framework. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through an outer-sphere electron transfer mechanism thus represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2019 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Chemical Reduction ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that the chemically reduced metal–organic framework A<i><sub>x</sub></i>Fe<sub>2</sub>(BDP)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; BDP<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which features coordinatively-saturated iron centers, is capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. Through a combination of gas adsorption measurements, single-crystal X-ray diffraction, and numerous spectroscopic probes, including <sup>23</sup>Na solid-state NMR and X-ray photoelectron spectroscopy, we demonstrate that selective O<sub>2</sub> uptake likely occurs as a result of outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the framework. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through an outer-sphere electron transfer mechanism thus represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2020 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Adsorption Mechanism ◽  
Selective Adsorption ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; bdp<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including <sup>23</sup>Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O<sub>2</sub> uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate similar O<sub>2</sub> uptake behavior to that of A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> in an expanded-pore framework analogue and thereby gain additional insight into the O<sub>2</sub> adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2020 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Adsorption Mechanism ◽  
Selective Adsorption ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that chemically reduced metal–organic framework materials of the type A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; bdp<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which feature coordinatively saturated iron centers, are capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. A combination of gas adsorption analysis, single-crystal X-ray diffraction, magnetic susceptibility measurements, and a range of spectroscopic methods, including <sup>23</sup>Na solid-state NMR, Mössbauer, and X-ray photoelectron spectroscopies, are employed as probes of O<sub>2</sub> uptake. Significantly, the results support a selective adsorption mechanism involving outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the structure. We further demonstrate similar O<sub>2</sub> uptake behavior to that of A<i><sub>x</sub></i>Fe<sub>2</sub>(bdp)<sub>3</sub> in an expanded-pore framework analogue and thereby gain additional insight into the O<sub>2</sub> adsorption mechanism. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through such an outer-sphere electron transfer mechanism represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

Overview of the effect of monomers and green solvents on thermoresponsive copolymers: phase transition temperature and surface properties

RSC Advances ◽  
2015 ◽  
Vol 5 (106) ◽  
pp. 86901-86909 ◽  
Author(s):  
P. Madhusudhana Reddy ◽  
Chi-Jung Chang ◽  
Shih-Rong Hsieh ◽  
Hsin-Chun Huang ◽  
Ming-Ching Lee
Keyword(s):  
Phase Transition ◽  
Ionic Liquids ◽  
Transition Temperature ◽  
Surface Properties ◽  
Phase Transition Temperature ◽  
Green Solvents

The thermoresponsive and surface properties of PNIPAM based copolymers were investigated in response to green solvents, ionic liquids.

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