Second-sphere coordination complexes via hydrogen bonding: Synthesis, spectroscopic characterization, crystal structures and packing of cis-diazidobis(ethylenediamine)cobalt(III) cations with complex fluoroanions

Crystals of cis-diazidobis(ethylenediamine)cobalt(III) tetrafluoroborate nitrate [cis-Co(en)2(N3)2]2 (BF4) (NO3) I and cis-diazidobis(ethylenediamine)cobalt(III) hexafluorosilicate, [cis-Co(en)2(N3)2]2(SiF6) II have been obtained by slowly mixing the separately dissolved cis-diazidobis(ethylenediamine)cobalt(III) nitrate with sodium salt of tetrafluoroborate and hexafluorosilicate in aqueous medium in 1:1 and 2:1 molar ratio, respectively. Elemental analyses and spectroscopic techniques (IR, UV/visible, 1H and 13C NMR) were studied for characterizing the complex salts. Single crystal X-ray structure determinations revealed supramolecular assemblies via hydrogen bonding network between ionic groups and NH2 group of coordinated ethylenediamine molecules, i.e. second-sphere coordination.