Directed assembly of transition-metal-coordinated molecular loops and squares from salen-type components. Examples of metalation-controlled structural conversion

Shih Sheng Sun, Charlotte L. Stern, Son Binh T. Nguyen, Joseph T. Hupp

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A series of transition-metal-containing molecular "loops" and "squares" has been prepared via a directed-assembly approach and characterized. The molecular loops were prepared from the reaction of cis-(PEt3)2Pt(OTf)2 with bis(4-pyridyl)-functionalized free-base salen-type ligands. Zn(II)-metalation of the salen-type ligands in the molecular loops converts the loops to molecular squares. Alternatively, the squares can be obtained by the directed assembly of cis-(PEt3)2Pt(OTf)2 and bis(4-pyridyl)-functionalized Zn(II)-salen-type ligands. A concentration-dependent dynamic equilibrium between cyclic species was observed when bis(3-pyridyl)-functionalized free-base salen-type ligand was employed in the reaction. Zn(II) or Cr(III) metalation of the free-base ligand shifted the equilibrium to the single dimeric species. The incorporation of multiple reactive metal sites into a single, cavity-containing supramolecular structure points toward catalytic applications for these new assemblies.

Original languageEnglish
Pages (from-to)6314-6326
Number of pages13
JournalJournal of the American Chemical Society
Issue number20
Publication statusPublished - May 26 2004


ASJC Scopus subject areas

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

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