Polynuclear iron(III) pivalates

The formation of magnetically active polynuclear FeIII pivalates in the FeSO4·7H2O-KOOCCMe3 system was studied. The reaction of FeSO4·7H2O (1) with KOOCCMe3 in EtOH in air afforded the antiferromagnetic trinuclear complex [Fe3O(OOCCMe3)6(H2O)3]+[OOCCMe3]−·3EtOH. A change of the solvent (EtOH) in this system to a 40:1 benzene—THF mixture resulted in the formation of the antiferromagnetic hexanuclear cluster [Fe6(O)2(OH)2(OOCCMe3)12(HOOCCMe3)(THF)]·1.5C6H6. The addition of trimethylacetic acid to EtOH and recrystallization from hexane gave rise to the antiferromagnetic coordination polymer [K2Fe4(O)2(OOCCMe3)10(HOOCCMe3)2(H2O)2]n (7). Recrystallization of the latter from acetonitrile afforded the antiferromagnetic tetranuclear complex K2Fe4(O)2(OOCCMe3)10(HOOCCMe3)2(MeCN)2. The structures of these compounds were established by X-ray diffraction analysis, and their magnetic susceptibilities and thermal decomposition were investigated.