Synthesis, Structure and Solid-Phase Transformations of Fe Nitrosyl Complex Na2[Fe2(S2O3)2(NO)4] · 4H2O

Abstract

Binuclear iron nitrosyl complex Na2[Fe2(S2O3)2(NO)4] · 4H2O (I) was synthesized by the reaction of iron(II) sulfate with sodium thiosulfate in the flow of NO gas. According to X-ray diffraction data, the [Fe2(S2O3)2(NO)4]2− anion has binuclear centrosymmetric structure with Fe atoms bonded by the µ-S atoms of thiosulfate groups. The isomeric shift for complex I δ=0.168(1) mm/s and quadrupole splitting ΔE Q =1.288 mm/s at T=80 K. When heated, complex I transforms to Na2[Fe2(S2O3)2(NO)4] (II), whose unit cell parameters found by X-ray diffraction method differ from those of complex I. The process of transformation of I to II was studied by calorimetric method. Complex I transforms to complex II without chemical decomposition, which was confirmed by IR and mass spectroscopy data.