C. Raptopoulou, ‡. A. Vaslis Tangoulis, V. Psycharis
Sep 9, 2000
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0
Influential Citations
41
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Journal
Inorganic Chemistry
Abstract
The use of orotic acid (H3L) in iron(III) chemistry has yielded a structurally, magnetically, and spectrochemically very interesting complex. The 1:3:3 FeCl3·6H2O/H3L/aqueous NH3 reaction system in MeOH gives red (NH4)[Fe3(μ3-OH)(H2L)3(HL)3]·7.75H2O (1) in high yield. 1 crystallizes in the hexagonal space group P3 with (at 25 °C) a = 14.813(7) A, c = 15.084(7) A, and Z = 2. There is a C3 axis passing through the central hydroxo oxygen; thus, the three FeIII atoms form an equilateral triangle with an edge of 3.312 A and the Fe3Ohydroxy core is planar. The orotates present two novel coordination modes; each H2L- ligand bridges two FeIII atoms through its syn,syn η1:η1:μ2 carboxylate group, while HL2- simultaneously chelates one FeIII atom through one carboxylate oxygen and the deprotonated amide nitrogen, and is bonded to a second metal ion through the adjacent carbonyl oxygen. The three H2L- and the three HL2- ligands lie above and below the Fe3Ohydroxy plane, respectively. Hydrogen bonds between the orot...