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rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
2005-12-7
pubmed:abstractText
This paper describes the self-assembly of a new class of foldamer-based molecular tweezers, whose rigid folded conformations are stabilized by intramolecular hydrogen bonding. Two zinc porphyrin units are introduced to the ends of molecular tweezers Zn(2)1 and Zn(2)2, while three zinc porphyrin units are incorporated to the S-shaped bi-tweezers Zn(3)3, which may be regarded as a combination of two Zn(2)1 molecules. Due to the preorganized U-shaped feature, Zn(2)1 and Zn(2)2 are able to strongly complex C60, C70, and C60 derivative 25 in chloroform or toluene in a 1:1 binding stoichiometry, whereas Zn(3)3, which possesses two tweezer units, complexes the guests in a 1:2 stoichiometry. More stable complex Zn(3)3.24 is formed between Zn(3)3 and 24, a linear molecule bearing two C60 moieties at the ends, as a result of the cooperative interaction of two binding sites. Chiral induction is observed for all the three receptors upon complexation with C60-incoporated chiral phenylalanine derivative 29, although the complexation of 29 by the folding receptors is pronouncedly weaker than that of C60 and 25 due to increased steric hindrance. The driving force for the formation of the complexes is the well established pi-pi stacking between the zinc porphyrin and fullerene units. The 1H and 13C NMR, UV-vis, fluorescent, and circular dichroism spectroscopy have been used to investigate the complexing behavior of the folding receptors and the fullerene guests. The association constants of the corresponding complexes in toluene and chloroform (if possible) have been evaluated with the UV-vis and fluorescent titration experiments.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Dec
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
127
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
17460-8
pubmed:year
2005
pubmed:articleTitle
Hydrogen-bonding-driven preorganized zinc porphyrin receptors for efficient complexation of C60, C70, and C60 derivatives.
pubmed:affiliation
State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China.
pubmed:publicationType
Journal Article