| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
[part 1] In order to develop podands which form intramolecular hydrogen bonding, new pordands 1, 2 and 3 having OH group in both ends have been synthesized. Bis(2'-hydroxyethyl) 2,6-pyridinedicarboxylate (1) was prepared by the reaction of pyridinedicarboxy acid and ethylene glycol and the structure was characterized in solid (fourier trans form-ir and X-ray analyses), in liquid (^1H and ^<13>C nmr titrations), and in the gas-phase (fast atom bombardment (fab) ms). Two bis(2'-hydroxyethy) 2,6-pyridinedicarboxylate molecules each with an included water molecule are bound together through hydrogen bonding to give a pseudo-macrocycle in the solid state and in chloroform solution. The FAB mass spectrum also suggested that ligand 1 forms a dimer in the gas-phase. In this part, we have demonstrated that ligand 1 forms apseudo-crown ether-like structure in the solid state and in solution. Also, ligand 1 forms a 1:1 complex with water and a dimer in gas phase. Complexalion studies of metal cat
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ions and organic guests by the new ligand are in progress.
[part 2] New podands capable of having intramolecular hydrogen bonding (2 and 3) have been synthesized. Molecular modeling (conformer search, AMI optimization and 3-21G(*) calculations) suggest that podand 2, which was prepared by the reaction of pyridinedimethanol dilosylate with catechol, and podand 3, which was prepared by the reaction of pyridinedimethanol with salicylic acid, form cyclic and non-cyclic structures, respectively. Podand 2 was prepared by the reaction of pyridinedimethanol ditosylate with catechol in the presence of Na_2C0_3 in acetonitrile in 41% yield. Dimerizalion product 4 was also isolated as a by-product in 3% yield. Podand 3 was prepared from pyridinedimethanol and salicylic add in the presence of DCC/DMAP in CH_2Cl_2 in 41% yield. Structures of new podands 2 and 3 were confirmed by ^1H and ^<13>C NMR, MS, FT-IR, elemental analyses, and X-ray crystallography. In this part, we have demonstrated that a podand which forms a pseudo-cyclic structure by hydrogen bonding shows higher affinity for metal ions than a podand which forms a non-cyclic structure. The X-ray crystal structure of the 2-NaSCN complex is also reported. Less
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