Synthesis, crystal structures and magnetic properties of mononuclear tris(croconate)ferrate(III) complexes

A straightforward synthetic method to prepare mononuclear croconato-containing iron (III) complexes, (A)3[Fe(C5O5)3] [A = tetrabutylammonium = n -Bu4N+ (1) and View the MathML sourcetetraphenylphosphonium=PPh4+(2);C5O52-=croconate=dianionof4,5-dihydroxycyclopent-4-ene-1,2,3-trione] along with their crystal structures and magnetic properties, are reported. The Fe(III) atom adopts a pseudo-octahedral geometry while magnetic susceptibility measurements, in the 2–300 K temperature range, show the occurrence of a high spin state (S = 5/2) in both complexes.