1990 Fiscal Year Final Research Report Summary
Optical Resolution and Its Mechanism of Metal Complexes Based on the Chiral Discrimination Between Ions of the Same Sign
| Project/Area Number |
01540513
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機・錯塩・放射化学
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| Research Institution | Ehime University |
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Principal Investigator |
KOINE Norio Ehime University, Faculty of Engineering, Lecturer, 工学部, 講師 (20036247)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Chiral Discrimination / Optical Resolution / Induced Circular Dichroism / Pfeiffer Effect / Chromatography |
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| Research Abstract |
Recently, we have first reported the chromatographic complete optical resolution based on the chiral discrimination between ions of the same sign. The purpose of this work is to elucidate the nature of this unexpected phenomenon.
(1) Column chromatographic optical resolution of twenty-six cobalt (III) racemates were carried out using as a chiral eluent an aqueous solution of [Sb_2 (d-tart) _2]^<2->. More than half of the racemates employed were completely resolved. From the comparison of the elution ordersof enantiomers and separation factors obtained for the racemates, we speculated the discrimination mechanism which was induced by the diastereomeric interaction between the chiral solvent sheaths about the selector and racemate.
(2) Pfeiffer effect of [Cr(ox)_3]^<3-> served by [Sb_2(d-tart)_2]^<2-> and its two analogues, [Cr_2(d-tart)(d-tartH)(bpy or phen)_2]^- and the induced CD of the cobalt (III) complexes served by [Sb_2(d-tart)_2]^<2-> were measured. For both chiral discrimination
… More
phenomena, the observed mean strength is unexpectedly comparable to those obtained for the phenomena between ions of opposite sign. In contrast, the strength are extremely small for the same phenomena served by d-tart^<2-> instead of the three binuclear complexe. These facts is suggestive of a contribution characteristic of the binuclear complexes. Preliminary experiments indicate the formation of liquid-crystalline in a [Cr_2(d-tart)(dtartH)(phen)_2]^- - H_2O system. These facts suggest that a factor of the present discrimination is involved in the solution structure of the binuclear complexes. Under these circumstances, X-ray crystallographic analysis of H[Cr_2(d-tart)(d-tartH)(bpy)_2]・3.5H_2O was performed. It was found that columns are formed in the crystal and the columns are connected by hydrogen bonding with the waters of crystallization. This molecular array suggests the formation of a chiral field in an aqueous solution and is very interesting in connection with the present chiral discrimination mechanism. Less
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