2000 Fiscal Year Final Research Report Summary
Studies on Hydrophobic Association of Metal Complexes and on Structures and Properties of Oil-like State
| Project/Area Number |
10440197
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic chemistry
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| Research Institution | YOKOHAMA CITY UNIVERSITY |
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Principal Investigator |
YOKOYAMA Haruhiuko YOKOHAMA CITY UNIVERSITY, FACULTY OF SCIENCE, PROFESSOR, 理学部, 教授 (10094319)
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| Project Period (FY) |
1998 – 2000
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| Keywords | oil-like state / phase separation / stacking / hvdrophobic interaction / supramolecule / metal complex / phenanthroline / solution X-ray diffraction |
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| Research Abstract |
1.Strong ion association was observed between [M (en)(phen)]^<2+> (M=Pt or Pd) complexes and 1-naphthaleneacetate ions by X-ray diffraction and conductivity measurements.
2.The solubility of 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy) for water was remarkably increased in the presence of the above metal complexes.
3.Radial distribution functions obtained by X-ray diffraction measurements of aqueous solutions dissolving [M (en)(phen)]^<2+> and phen revealed several periodic peaks having 3.5Å intervals, suggestine the existence of supramolecules having the layer structure formed by the stacking of aromatic rings of the complex and phen molecules.
4.A saecific ahenomenon was found that an aqueous solution of naphthalenesulfonate (1-NS or 2-NS) of [M (phen)_3]^<3+> or [M (bpy)_3]^<3+> (M=trivalent metal) was separated into two liquid phases of dilute and concentrated solutions in a given composition range. Their phase diagrams, similar to that of the phenol-water system, had the critical solution temperature (T_c) above which the phase-separation phenomenon disappeared. The T_c for the phen complex was significantly larger than that for the bpy complex, and the T_c for the 1-NS salt was somewhat larger than that for the 2-NS salt.
5.From X-ray diffraction measurements of concentrated aqueous solutions of [M (bpy)_3] (1-NS)_3 it was found that complexes were aggregated in solutions, a part of aromatic rings of 1-NS^- penetrated into the hydrophobic pockets of the complexes, and the solution structure was almost independent of temperature. Density fluctuations due to the localization of water molecules were observed in solutions having compositions just before the phase separation as the diffraction intensity increased at lower angles.
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