Synthesis, crystal structure and characterization of chiral, three-dimensional anhydrous potassium tris(oxalato)ferrate(III)

摘要

The synthesis, crystal structure and physical properties of chiral, three-dimensional anhydrous potassium tris(oxalato)ferrate(III) [K _3F _e(C _2O _4) _3] are described. X-ray analysis reveals that the compound crystallized in the chiral space group P4 _132 of cubic system with a=b=c=13.5970(2), Z=4. The structure of the complex consists of infinite anionic [Fe(C _2O _4) _3] ~(3-) units with distorted octahedral environment of iron surrounded by six oxygen atoms of three oxalato groups. The anionic units are interlinked through K ions of three different coordination environments of distorted octahedral, bicapped trigonal prismatic and trigonal prismatic yielding a three-dimensional motif. The two broad absorption bands at 644 and 924 nm from UV-vis-NIR transmittance spectra were ascribed to a ligand-to-metal charge transfer. The room temperature crystalline EPR spectra indicate the high-spin (S=5/2) of Fe(III) ion. The vibrating sample magnetometer measurement shows the paramagnetic nature at room temperature. Thermal studies of the compound confirm the absence of water molecule.