2000 Fiscal Year Final Research Report Summary
Studies on Macrocyclic Conjugated Compounds Having Three-dimensional π-Systems
| Project/Area Number |
11440189
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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 |
Organic chemistry
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| Research Institution | Osaka University |
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Principal Investigator |
KAWASE Takeshi Graduate School of Science, Osaka University Associate Professor, 大学院・理学研究科, 助教授 (10201443)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Supramolecule / Fullerenes / Belt-shaped conjugated systems / Complexation / Supramolecular interaction |
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| Research Abstract |
New carbon allotropes having a carved conjugated system such as fullerenes and carbon anotubes have been extensively studied from physical and chemical viewpoints. However, the supramolecular properties of the hollow of these materials have not been known well. We have recently synthesized a series of [n]CPPAs (cyclic paraphenylacetylenes) 1a-d (n=6〜9) having a belt-shaped conjugated system as relatively stable compounds. They can be regarded as good model compounds for investigating the supramolecular properties of inner space of carved conjugated systems.
During the period, we have found interesting host properties of CPPAs as the following.
1) Crystallographic analysis of an inclusion complex of 1a and hexamethylbenzene reveals that 1a has a belt-shaped structure with 13.2 Å of diameter as expected by theoretical calculation.
2) Crystallographic analysis of an inclusion complex of 1a and a methanofullerene derivative 2 also reveals that the C60 cage of 2 is situated at somewhat floating position in a bowl-shaped cavity of 1a.
3) The association constants for the complexation of various CPPA analogs with fullerenes were determined by the titration experiments by means of fluorescence spectra to discuss the stability of these complexes. The association constants for both C60 and C70 complexes are bis(2,6- naphthyl)[6]CPPA 3 > 1a > 1b in order, and the order of the selectivity between the complexes are 3 > 1b >1a, respectively.
4) CPPAs 1a and 1d forms a 1 : 1 complex in solid as well as in solution. Within our knowledge, it is the first inclusion complex between hydrocarbons in non-polar solvents.
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