Reversible Catenation of Coordination Rings with Pd(ii) and/or Pt(ii) Metal Centers: Chirality Induction Through Catenation

Akiko Hori, Hisashi Kataoka, Akihiko Akasaka, Takashi Okano, Makoto Fujita

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

A Pd(II)-linked coordination ring is reversibly transformed into its catenanted dimer at room temperature through the efficient organic stacking of the component rings. An analogous Pt(II)-linked ring is also catenated only at high temperature (100 °C), but not at room temperature because of the kinetic inertness of Pt(II)-ligand interaction. Interestingly, the combination of the Pd(II)- and the Pt(II)-linked coordination rings selectively gives a Pd(II)/Pt(II) cross-catenane, because the kinetically inert Pt(II) ring can be catenated only via the dissociation of the kinetically labile Pd(II) ring. Planer conformation of the monomer rings is twisted upon catenation, inducing helical chirality in the catenated structure. Thus, induced circular dichroism (ICD) is observed in the catenation when chiral-1,2-cyclohexandiamine is attached as a chiral auxiliary on the metal centers. The ICD decreases with increasing temperature due to less effective chiral aromatic stacking at higher temperature. The Pd(II) ring shows higher ICD than the Pt(II) ring, probably due to the more flexible conformation of the Pd(II) ring that can adopt chiral orientation easily.

Original languageEnglish
Pages (from-to)3478-3485
Number of pages8
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume41
Issue number22
DOIs
Publication statusPublished - 2003 Nov 15
Externally publishedYes

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Keywords

  • Induced circular dichroism
  • Palladium
  • Platinum
  • Reversible catenation

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry

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