Design and synthesis of a C4-symmetrical hard-soft ditopic metal receptor by calixarene-porphyrin coupling

Takeshi Nagasaki, Hiroyuki Fujishima, Masayuki Takeuchi, Seiji Shinkai

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40 Citations (Scopus)


A tetraphenylporphyrin capped with a calix[4]aryl amide through L-alanine pillars (compound 1) has been synthesized. Owing to C4 symmetry in both the tetraphenylporphyrin and the calix[4]arene this molecule still retains C4 symmetry. As the calix[4]aryl amide moiety can bind alkali metal cations, and the porphyrin moiety can bind transition metal cations, compound 1 acts as a host molecule with a hard-soft ditopic metal-binding site. It was found that the ZnII complex of 1 (complex 1-ZnII) can bind KI very strongly with log Kass = 5.23 (CHCI3:MeCN = 4:1 v/v; 25 °C) whereas KC104 is scarcely captured by 1-ZnII. Absorption and fluorescence spectroscopic studies showed that I- ion is bound to this cavity, interacting with both calix[4]arene-bound K+ through electrostatic attraction and porphyrin-bound ZnII through coordination as an axial ligand. The results establish that complex 1-ZnII acts as a unique ditopic receptor for I- ion.

Original languageEnglish
Pages (from-to)1883-1888
Number of pages6
JournalJournal of the Chemical Society, Perkin Transactions 1
Publication statusPublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)

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