Hydrogen-bonding interactions, geometrical selectivity and spectroscopic properties of cobalt(III) complexes with unsymmetrical tridentate amine-amidato-phenolato type ligands

Ryoji Mitsuhashi, Takayoshi Suzuki, Yukinari Sunatsuki, Masaaki Kojima

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Four cobalt(III) complexes with the formula of [Co(Ln)2] - bearing tridentate amine-amidato-phenolato-type ligands (Ln: n = 1-4) were synthesized. All of the complexes were characterized by 1H NMR spectroscopy and X-ray analysis. The geometrical selectivity was found to depend on the flexibility of the amine-amidato chelate in combination with the planar 2-oxybenzamido 6-membered chelate; that is, the amine-amidato 5-membered chelate took the mer-type geometry, and the 6-membered chelate took the fac-type geometry. In most of the mer-type complexes, intermolecular double hydrogen bonds via amidato(O) and amino group were selectively formed between their enantiomeric pairs of mononuclear complexes. In the case of two chiral ligands {L22- = 2-amino-1-(2-oxybenzamido)propane; L32- = trans-1-amino-2-(2-oxybenzamido)cyclohexane}, [Co(L3)2]- showed diastereoselectivity while [Co(L2)2]- did not. Furthermore, PPh4[Co(L1)2] (L12- = 2-amino-1-(2-oxybenzamido)-2-methylpropane) showed an apparent solvatochromic behavior in several solvents. Although the molecular structures of [Co(L2 or L3)2]- are quite similar to that of [Co(L1) 2]-, these complexes did not exhibit such a solvatochromic behavior.

Original languageEnglish
Pages (from-to)131-137
Number of pages7
JournalInorganica Chimica Acta
Volume399
DOIs
Publication statusPublished - Apr 1 2013

Keywords

  • Amine-amidato type ligand
  • Diastereoselectivity
  • Double hydrogen bonds
  • Geometrical isomers
  • Solvatochromism

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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