Non‐Oxido Mixed‐Valence Mn II 6 Mn III 4 Cluster with Benzoate, Triethanolamine and Phosphonate Bridging Ligands

The synthesis, structure and magnetic properties of a new non‐oxido mixed‐valence decanuclear heterometallic manganese cluster [K 3 Mn 10 (PhCOO) 10 (PhPO 3 ) 2 (Htea) 6 ](PhCOO) · 6MeCN} n ( 1 ), where Htea 2– is the dianion of triethanolamine, is reported. Compound 1 can be regarded as an analogue of 24‐metallacrown‐10, acting as a host for three potassium ions. The resulting {Mn 10 } cage crystallises as a cation; benzoate anions link the cages into a 1D polymer within the crystal. Direct current magnetic susceptibility measurements were collected at temperatures between 1.8 and 300 K and applied magnetic fields of 1 and 10 kG. The room‐temperature value is very close to the spin‐only value of 38.25 cm 3  mol –1  K expected for an Mn 10 ‐cage repeat unit comprising six Mn II and four Mn III ions. At 2 K and 70 kG the magnetisation reaches a value of 19.5 Nμ B , suggesting a ground state larger than S = 10.