2007 Fiscal Year Final Research Report Summary
Total-reflection XAFS of metal complex adsorbed at liquid-liquid interface
| Project/Area Number |
18550087
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Analytical chemistry
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| Research Institution | Japan Synchrotron Radiation Research Institute |
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Principal Investigator |
TANIDA Hajime Japan Synchrotron Radiation Research Institute, Research & Utilization Division, XAFS & Element Spectroanalysis Team, Associate Senior Scientist (70301760)
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| Co-Investigator(Kenkyū-buntansha) |
NAGATANI Hirohisa Nagasaki University, Faculty of Engineering, Assistant Professor (90346297)
HARADA Makoto Tokyo Institute of Technology, Graduate School of Science and Engineering, Assistant Professor (60313326)
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| Project Period (FY) |
2006 – 2007
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| Keywords | liquid-liquid interface / total-reflection / XAFS / surfactant / bromide ion / concentration / hydration structure |
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| Research Abstract |
The liquid-liquid interface between two immiscible solutions is an important two-dimensional reaction field used in a separation science and synthesis of thin-layer materials, and also as a model of biomembrane. The structure analysis of the interfacial species is very important to understand an adsorption and heterogeneous reaction mechanisms. The coordination structure of the interfacial species, however, has not been studied in detail, because of the lack of a suitable technique. Total-reflection X-ray spectroscopic technique was developed to the liquid-liquid interface. The X-ray absorption fine structure(XAFS) spectrum of bromide ion at the heptane-water interface was successfully obtained in the fluorescence mode. The spectra at the Br K-edge for bromide ions concentrated at the heptane-water interface was observed in the presence of cationic surfactants such as dimethyldipalmitylammonium, dimethyldilaurylammonium and, stearyltrimethylammonium jons. A significant difference of spectra at the heptane-water interfaces in the presence of catonic surfactants demonstrated that the hydration structure of Br-with cationic surfactants at the heptane-water interface was different from neat interfaces or bulk water phases. The spectrum at the Zn K-edge for zinc ions at heptane-water interface was also observed. The zinc ion was concentrated at the interface in the presence of stearic acid. The new method will lead to in situ study the interfacial concentration profile and the coordination structure of interfacial species. Further improvements and applications to metal ions and metal complexes in various liquid-liquid systems are also going on.
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