Catenanes built around octahedral transition-metal complexes that contain two intertwined endocyclic but non-sterically hindering tridentate ligands

Jean François Ayme, Jacques Lux, Jean Pierre Sauvage, Angélique Sour

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Sterically hindering bidentate chelates, such as 2,9-diphenyl-1,10- phenanthroline, form entwined complexes with copper(I) and other tetrahedrally coordinated transition-metal centres. To prepare octahedral complexes containing two entwined tridentate ligands and thus apply a strategy similar to that used for making catenanes with tetrahedral metal centres, the use of the classical terpy ligand (terpy=2,2′:6′,2″-terpyridine) appears to be attractive. In fact, 6,6″-diphenyl-2,2′:6′,2″- terpyridine (dp-terpy) is not appropriate due to strong "pinching" of the organic backbone by coordination to the metal and thus stable entwined complexes with this ligand cannot be obtained. Herein, we report the synthesis and coordination properties of a new family of tridentate ligands, the main features of which are their endocyclic nature and non-sterically hindering character. The coordinating fragment consists of two 8'-phenylisoquinolin-3'-yl groups attached at the 2 and 6 positions of a pyridine nucleus. Octahedral complexes containing two such entangled ligands around an octahedral metal centre, such as Fe II, Ru II or Co III, are highly stable, with no steric congestion around the metal. By using functionalised ligands bearing terminal olefins, double ring-closing metathesis leads to [2]catenanes in good yield with Fe II or Co III as the templating metal centre. The X-ray crystallography structures of the Fe II precursor and the Fe II catenane are also reported. These show that although significant pinching of the ligand is observed in both Fe II complexes, the system is very open and no steric constraints can be detected.

Original languageEnglish (US)
Pages (from-to)5565-5573
Number of pages9
JournalChemistry - A European Journal
Volume18
Issue number18
DOIs
StatePublished - Apr 27 2012

Keywords

  • catenanes
  • entwined ligands
  • isoquinoline
  • transition metals
  • tridentate ligands

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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