Syntheses, characterisation and crystal structures of ferrocenyl β−diketones and their Schiff base N[sbnd]N[sbnd]O ligand derivatives with 2-picolylamine

Vania Artigas, Deborah González, MAURICIO DANIEL FUENTEALBA CARRASCO

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Ferrocenyl β-diketones compounds β3-4 were synthesised by Claisen condensation reaction between acetylferrocene and ethyl benzoate or 4-bromoethyl benzoate. We also synthesised four new Schiff base ligands L1-4 by condensation reaction between β1-4 and 2-picolylamine. Identities of all these compounds were confirmed by satisfactory elemental analysis, 1H nuclear magnetic resonance (NMR) correlation and infrared (IR) spectroscopy. In addition, all these compounds were authenticated by a single-crystal X-ray diffraction analysis. In solution, 1H NMR spectra of β3 and β4 exhibit a mixture of keto:enol tautomer ratios of 12:88 and 8:92, respectively, calculated by the integration of the free cyclopentadienyl ring. In contrast, the proton NMR spectra of L1-4 showed only the keto-enamine tautomer displacements. In addition, decoupled 13C NMR spectrum clearly confirmed the existence of these tautomers. These results are in accordance with X-ray crystallographic studies, in which the enol and keto-enamine forms were elucidated for β-diketones and Schiff base ligands, respectively.

Original languageEnglish
Pages (from-to)325-332
Number of pages8
JournalJournal of Molecular Structure
Volume1129
DOIs
StatePublished - 5 Feb 2017

Keywords

  • Ferrocenyl fragment
  • Schiff base ligand
  • β−diketone tautomers

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