Binding of fluoroanions by a cationic cobalt(III) complex: syntheses, characterization and single crystal X-ray structure determination of [Co(phen)2CO3]BF4 and [Co(phen)2CO3]PF6·3H2O

Raj Pal Sharma, Ajnesh Singh, Paloth Venugopalan, William T. A. Harrison

Research output: Contribution to journalArticle

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Abstract

In an effort to utilize the cationic cobalt(III) complex as a binding agent for fluoroanions, the reaction of carbonatobis(1,10-phenanthroline)cobalt(III) chloride with sodium tetrafluoroborate and sodium hexafluorophosphate in water (1:1 M ratio) leads to the formation of [Co(phen)(2)CO3]BF4 (1) and [Co(phen)(2-)CO3]PF6 center dot 3H(2)O (2). These cobalt(III) complex salts have been characterized by elemental analyses, spectroscopic techniques (multinuclear NMR, UV/Visible and FT-IR), solubility product and conductance measurements. X-ray structure determination of these complex salts revealed the presence of ionic structures i.e., one complex cation [Co(phen)(2)CO3](+) and one BF4- anion in 1 and one complex cation [Co(phen)(2)CO3](+), one PF6- anion and three water molecules of crystallisation in 2. The packings in both complex salts are stabilized by C-H center dot center dot center dot F, C-H center dot center dot center dot O(carbonato) hydrogen bonds and anion center dot center dot center dot pi interactions beside electrostatic forces of attraction. In addition to these non-covalent interactions, O-H center dot center dot center dot O(water) and pi-pi stacking interactions are also observed in 2. The formation of complex salts of definite composition with tetrafluoroborate and hexafluorophosphate ions suggest that [Co(phen)(2)CO3](+) may be used as binding agent for weakly coordinating fluoroanions i.e. BF4- and PF6-. (C) 2011 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)6-12
Number of pages7
JournalJournal of Molecular Structure
Volume994
Issue number1-3
Early online date24 Feb 2011
DOIs
Publication statusPublished - 17 May 2011

Keywords

  • second sphere coordination
  • 1,10-Phenanthroline
  • tetrafluoroborate
  • hexafluorophosphate
  • anion receptor
  • x-ray crystallography
  • 2ND sphere coordination
  • organic anion receptors
  • hydrogen-bond patterns
  • graph-set analysis
  • spectroscopic characterization
  • ionic liquids
  • chemistry
  • sulfate
  • design

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