New Mixed-Valent Mn Clusters from the Use of N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine (edteH4): Mn3, Mn4, Mn6, and Mn10

The syntheses, crystal structures, and magnetochemical characterization are reported for the new mixed-valent Mn clusters [Mn2IIMnIII(O2CMe)2(edteH2)2]­(ClO4) (1), [MnII2MnIII2(edteH2)2(hmp)2Cl2]­(MnIICl4) (2), [MnIII6O2(O2CBut)6(edteH)2(N3)2] (3), [Na2MnIII8MnII2O4(OMe)2(O2CEt)6(edte)2(N3)6] (4), and (NEt4)2[Mn8IIIMn2IIO4(OH)2-(O2CEt)6(edte)2(N3)6]­(5), where edteH4 is N,N,N′,N′-tetrakis-(2-hydroxyethyl)­ethylenediamine and hmpH is 2-(hydroxymethyl)­pyridine. 1–5 resulted from a systematic exploration of the effect of different Mn sources, carboxylates, the presence of azide, and other conditions, on the Mn/edteH4 reaction system. The core of 1 consists of a linear MnIIMnIIIMnII unit, whereas that of 2 is a planar Mn4 rhombus within a [MnII2MnIII2(μ3-OR)2] incomplete-dicubane unit. The core of 3 comprises a central [MnIII4(OR)2] incomplete-dicubane on either side of which is edge-fused a triangular [MnIII3(μ3-O)] unit. The cores of 4 and 5 are similar and consist of a central [MnII2MnIII2(μ3-OR)2] incomplete-dicubane on either side of which is edge-fused a distorted [MnIIMnIII3(μ3-O)2(μ3-OR)2] cubane unit. Variable-temperature, solid-state direct current (dc) and alternating current (ac) magnetization studies were carried out on 1–5 in the 5.0–300 K range, and they established the complexes to have ground state spin values of S = 3 for 1, S = 9 for 2, and S = 4 for 3. The study of 3 provided an interesting caveat of potential pitfalls from particularly low-lying excited states. For 4 and 5, the ground state is in the S = 0–4 range, but its identification is precluded by a high density of low-lying excited states.