Syntheses and Structures of μ-Oxo-Bis[dichloroiron(III)]-Bis-[2,6-Diacetylpyridinedioximate(-1)]Iron(II) and Related Compounds

Abstract

The syntheses and structures of four new compounds are described. Two of these compounds are the anhydrous and dihydrate chloride salts of the diamagnetic bis(2,6-diacetylpyridinedioxime)iron(II) cation, [Fe(DAPDH2)2]2+. In this complex cation the DAPDH2 ligand binds to the iron, as expected, through its three nitrogen atoms leaving the four oxime oxygen atoms protonated and uncoordinated. The third compound is (AsPh4)2[Fe2OCl6], a new salt of the well-known oxo-bridged diiron complex, [Fe2OCl6]2−. The synthesis of (AsPh4)2[Fe2OCl6] is a high yield, straightforward, one-step preparation starting with AsPh4Cl and ferrous chloride in methanol. In this synthesis Fe(II) is oxidized to Fe(III) by atmospheric O2. The fourth new compound is the novel and unexpected triiron complex [Fe(DAPDH)2Fe2OCl4]. This complex is derived from [Fe(DAPDH2)2)]2+ and [Fe2OCl6]2− by removing the H+ from each of two adjacent oxime oxygen atoms of the former and one Cl− from each of the Fe(III) ions of the latter. The resulting neu...