ARTICLE DOI: 10.1002/zaac.201000363 Synthesis and Properties of Complexes with Unusual {Mn III 4 } and {Mn II 4 } Cages Małgorzata Hołyńska, [a] Clemens Pietzonka, [a] and Stefanie Dehnen* [a] Dedicated to Professor Gernot Frenking on the Occasion of His 65th Birthday Keywords: Manganese; Cage compounds; Magnetic properties; Crystal structures Abstract. Two types of manganese complexes with [Mn 4 ] cores fea- turing the unusual distorted cube topology are presented, the first of which comprises new modifications of the reported complex [Mn III 4 (sao) 4 (saoH) 4 ]·3CHCl 3 : [Mn 4 (sao) 4 (saoH) 4 ]·1.32(C 4 H 10 O)· 0.43(CH 4 O) (1a) and [Mn(sao) 4 (saoH) 4 ]·0.5(CH 4 O)·0.5(C 2 H 3 N) (1b) sao = salicylaldoxime. The second, 0.55[Mn 4 Cl 4 (C 12 H 9 N 2 O) 4 - Introduction One of the most important directions in the studies on poly- nuclear manganese complexes, bearing magnetic properties and being models for biological systems, is the synthesis of compounds with unusual complex cores. [1] A number of “standard” cores is already known and modified in a targeted way, including the planar or “butterfly”-like topology. [2] An example of an extremely rare magnetic {Mn III 4 } core is a dis- torted cube with single molecule magnet (SMM) properties, which was first reported by Milios et al. with the complex [Mn III 4 (Me-sao) 4 (Me-saoH) 4 ] (A; Me-saoH 2 = 2-hydroxy- phenylethanoneoxime). [3] In A the manganese atoms are in- volved in ferromagnetic interactions, which lead to a S =8 ground state. In the unusual {Mn III 4 } cage, four Mn III atoms are linked through N–O oxime groups of the oxime ligand. The second known example of a compound with this core is a tetranuclear manganese(III) salicylaldoxime ensemble reported by Kumbhar et al., [Mn 4 (sao) 4 (saoH) 4 ]·3CHCl 3 (B). [4] In con- trast to A, compound B exhibits antiferromagnetic behavior with weakly coupled Mn 3+ atoms, which has been, however, not discussed so far. Recently, Inglis et al. carried out a study on a series of ferro- magnetic complexes with similar [Mn 4 ] distorted cubes of the general formula [Mn III 4 (R-sao) 4 (R-saoH) 4 ](R = Me, Napth, * Prof. Dr. S. Dehnen E-Mail: dehnen@chemie.uni-marburg.de [a] Fachbereich Chemie Wissenschaftliches Zentrum für Materialwissenschaften Philipps-Universität Marburg Hans-Meerwein-Strasse 35043 Marburg, Germany Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/zaac.201000363 or from the author. 556 © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Z. Anorg. Allg. Chem. 2011, 637, 556–561 (CH 3 OH) 2 (H 2 O) 2 ]·0.45[Mn 4 Cl 4 (C 12 H 9 N 2 O) 4 (CH 3 OH) 4 ](2), is the first reported case of a {Mn II 4 } core of this topology besides known {Mn III 4 } compounds. Differences between the {Mn II 4 } and {Mn III 4 } situation are discussed, and so far overlooked differences in magnetic properties between different {Mn III 4 } compounds are pointed out. Et). [5] This provided a better insight into this class of com- pounds, however, overlooking antiferromagnetic compound B. In this short communication we add three further compounds with an {Mn III 4 } distorted cubic core, two of which represent new modifications of compound B, and the second is a new compound, being the first such complex with terminal non- chelating chlorine ligands and thus an {Mn II 4 } core. The {Mn II 4 } compound exhibits antiferromagnetic coupling, whereas the two modifications of the {Mn III 4 } compound show either antiferromagnetic or ferromagnetic coupling between the four manganese atoms. Results and Discussion Syntheses Compounds [Mn 4 (sao) 4 (saoH) 4 ]·1.32(C 4 H 10 O)·0.43(CH 4 O) (1a), [Mn(sao) 4 (saoH) 4 ]·0.5(CH 4 O)·0.5(C 2 H 3 N) (1b) and 0.55[Mn 4 Cl 4 (C 12 H 9 N 2 O) 4 (CH 3 OH) 2 (H 2 O) 2 ]·0.45[Mn 4 Cl 4 - (C 12 H 9 N 2 O) 4 (CH 3 OH) 4 ](2) were prepared by self-assembly and solvothermal reactions, respectively, according to the reac- tions schemes given in Equation (1) and Equation (2).