Binding of fluoroanions by a cationic cobalt(III) complex: Syntheses, characterization and single crystal X-ray structure determination of [Co(phen)(2)CO3]BF4 and [Co(phen)(2)CO3]PF6 center dot 3H(2)O

作者：Sharma Raj Pal^*; Singh Ajnesh; Venugopalan Paloth; Harrison William T A

来源：Journal of Molecular Structure, 2011, 994(1-3): 6-12.

DOI：10.1016/j.molstruc.2011.02.040

• Second sphere coordination
• 1,10-Phenanthroline
• Tetrafluoroborate
• Hexafluorophosphate
• Anion receptor
• X-ray crystallography

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-.

• 出版日期2011-5-17