Heterometallic FeIII-CeIV complexes from the use of aliphatic aminoalcohol ligands

Six novel heteronuclear Fe-III/Ce-IV clusters with the ligands 3-amino-1-propanol (Hap) and 2-(hydroxymethyl)piperidine (Hhmpip) [(Fe4Ce6O8)-Ce-III-O-IV(L)(4)((CH3)(3)CCO2)(12)(RCO2)(4)] = CH3, L = ap(-), 1; R = ClCH2, L = ap(-), 2; R = BrCH2, L = ap(-), 3; R = C2H5, L = ap(-), 4; R = CH3, L = hmpip(-), 5) and aFe(2)Ce(2)Na(2)O(2) ((CH3)(3)CCO2)(8)(N-3)(2)(aP)(2)])(infinity). (6)(infinity) are reported. Compounds 1-5 were prepared from reactions of preformed trinuclear Fe3+ clusters with the ligands, in the presence of (NH4)(2)Ce(NO3)(5) and RCO2M (R = CH3, M+ = H+, 1; R = ClCH2, M+ = Na+, 2; R = BrCH2, M+ = Na+, 3; R = CH3CH2, M+ = Na+, 4; R = CH3, M+ = H+, 5) in 1:5:1:1 molar ratio in CH3CN. Complex (6 center dot 2CH(3)CN)(infinity) was prepared by a similar to the above described synthetic procedure that involved the use of NaN3 instead of RCO2M. To the best of our knowledge, compounds 1-6 are the initial examples of Fe-III/Ce-IV species and rare examples of metal complexes with the ligands Hap and Hhmpip. The structures of 1-5 are composed of a distorted supertetrahedral [(Fe4Ce6IV)-Ce-III(mu(4)-O)(4)(mu(3)-O)(4)](20+) structural core, while (6 center dot 2CH(3)CN)(infinity) displays a [(Fe2Ce2Na2)-Ce-III-Na-IV(mu(4)-O)(2)](12+) core consisting of two tetrahedral units sharing one common edge. These two structural types are rather uncommon for mixed metal 3d/4f compounds although they are well-known for 3d metal cluster chemistry. Variable temperature dc magnetic susceptibility studies on powdered microcrystalline samples of 1 and (6 center dot 2CH(3)CN)(infinity), revealed the presence of weak antiferromagnetic interactions as expected on the basis of the large separations (>6 angstrom) between the paramagnetic Fe3+ ions in both complexes. (C) 2012 Elsevier Ltd. All rights reserved.