A self-locking molecule operative with a photoresponsive key

Takahiro Muraoka, Kazushi Kinbara, Takuzo Aida

Research output: Contribution to journalArticlepeer-review

56 Citations (Scopus)

Abstract

Rotary host 1, composed of a ferrocene unit as a rotary module, is conformationally locked internally in apolar solvents such as benzene by a double intramolecular Zn-N coordination between the zinc porphyrin and aniline units, attached to each cyclopentadienyl (Cp) ring. Upon addition of the cis form of 1,2-bispyridylethylene (cis-2) to (+)-1 ([cis-2]/[(+)-1] = 5.0), an enantiomer of 1, the intramolecular Zn-N coordination bonds in (+)-1 are readily cleaved to form an externally locked, cyclodimeric one-to-one complex (+)-1⊃cis-2, accompanying a rotation of the ferrocene module, as visualized by CD spectroscopy. In contrast, use of trans-2, in place of cis-2, under otherwise identical conditions to the above, did not result in releasing the internal double lock of (+)-1. Such a large difference between the isomers of 2 in the affinity toward host 1, along with their capabilities of photochemical interconversion, allowed for the demonstration of a reversible self-locking operation of 1. Namely, the externally locked state of 1, as in the form of 1⊃cis-2, spontaneously retrieves the internally locked state, after the release of 2 from 1 upon cis-to-trans photochemical isomerization of ligating 2, while the backward photochemical isomerization of 2 in the presence of 1 results in switching of 1 to its externally locked state.

Original languageEnglish
Pages (from-to)11600-11605
Number of pages6
JournalJournal of the American Chemical Society
Volume128
Issue number35
DOIs
Publication statusPublished - 2006 Sep 6

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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