1993 Fiscal Year Final Research Report Summary
A Study on the Synthesis of Pyrimidinium Crowns as a Novel Anion-Receptor and Their Molecular Recognition Mechanisms
| Project/Area Number |
04671325
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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 |
Physical pharmacy
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
AOKI Katsuyuki Toyohashi Univ.Tech., Materials Science, Prof., 物質工学系, 教授 (30087514)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Host-guest chemistry / Molecular Recognition / Anion receptor / Macrocyclic pyrimidinium crown / Thiamine / Pyrimidine / Crystal structure |
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| Research Abstract |
(1) Thermal decomposition reactions of thiamine chloride gave at least four pyrimidinium-oligomers, which were detected by HPLC and were successfully separated by a column-chromatography. Investigations of the isolation of the oligomers and their characterization are under way.
(2) Aion salts of a methylene-bridged cationic pyrimidinium-dimer were synthesized, where anions are ClO_4^-, [Hg_2I_6]^<2->, or [Co(SCN)_4]^<2->. X-ray structure analyzes of the salts show that an anion molecule(s) is captured by a cationic pyrimidinium-dimer molecule(s) through (i) a C(pyrimidinium ring)-H...anion hydrogen-bonding and (ii) and anion...pyrimidinium-ring electrostatic interaction. These cation-anion interaction modes are analogous to those found in a chloride salt of cyclic pyrimidinium-tetramer (J.Am.Chem.Soc., 113, 7033 (1991)).
(3) X-ray structure analyzes of anion salts of a thiaminium cation, where anions are [Hg(SCN)_4]^<2->, [PtCl_6]^<2->, [PtCl_6]_<0.5>^-.Cl^-, [Pt(SCN)_4]^<2->, or [Pt(SCN)_6]^<2->, show that these salts also involve the same cation-anion interaction modes as those found in (2).
(4) X-ray structure analyzes of a thiaminium-monophosphate cation, where anions are CF_3SO_3^- or ClO_4^-, show that these salts also involve the same cation-anion interaction modes as those found in (2).
(5) Based on (2), (3) and (4), a principle of cation-anion recognition mechanism is presented, that is, (i) C(aromatic ring)-H...anion hydrogen-bonding and (ii) an anion...aromatic ring electrostatic interaction.
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