Spectroscopic Evidence of in situ Formation of a Novel Tetrakis(Tetrazolato)Iron Compound

In an attempt to synthesize the complex Fe(CN)₅(N₂)]^3- by reaction of NaFe(CN)₅(NO)]·2H₂O with azide followed by treatment with NOSbCl₆], a similar method to that used by Feltham to obtain trans-RuCl(N₂)(das)₂]Cl₂ from trans-RuCl(NO)(das)₂]Cl₂, we found spectroscopic evidence that excess azide reacts with the CN^- ligands to generate tetrazolato groups C-coordinated to Fe. Initial results suggest that the obtained compound is sodium azidotris(2H-tetrazolato)(5H-tetrazolato)iron(0). The spectroscopic evidence also indicates that these heterocycles are destroyed by reaction with NOSbCl₆], and the CN^- groups are regenerated. Here we present the characterization of these complexes by IR, ¹³C NMR, conductivity measurements, elemental analysis and magnetic susceptibility.