Binding of inorganic oxo-anions to cationic cobaltammine: Synthesis, characterization, X-ray structures determination and DFT calculations of [Co(NH3)(6)]Cl-2(ClO3), [Co(NH3)(6)]Br-2(ClO3) and [Co(NH3)(6)]Cl-2(IO3) ˖ 2(IO3)

Single crystals of [Co(NH3)(6)]Cl-2(ClO3) (1), [Co(NH3)(6)]Br-2(ClO3) (2) and [Co(NH3)(6)]Cl-2 (IO3) (.) H2O (3) suitable for X-ray structure determinations were obtained directly by reacting hexaamminecobalt(III) halide with appropriate metal halates in 1:1 molar ratio in hot aqueous medium. These hexaamminecobalt(III) complexes have been characterized by spectroscopic studies (e.g. UV/Visible and IR). Single crystal X-ray structure determination of title complex salts revealed the presence of discrete ions, i.e., cation [Co(NH3)(6)](3+) and mixed anions Cl- and ClO3- or Br- and ClO3 or Cl- and IO3- in the solid state. Crystal lattice is stabilized by electrostatic forces of attraction and hydrogen bonding interactions (N-H (...) O-, N-H (...) Cl- or N-H (...) Br-). The formation of definite salts of composition with halate ions suggests that [Co(NH3)(6)](3+) may be used as purely inorganic anion binding agent for these weakly coordinating oxo-anions. The DFT calculations have been carried out to calculate molecular volumes of the oxoanions and separation between two successive cation layers.