Incorporation of Hexanuclear Mn(II,III) Carboxylate Clusters with a {Mn6O2} Core in Polymeric Structures

A new series of hexanuclear mixed-valent carboxylate coordination clusters of the type [Mn6O2(O2CR)(10)L-4] (R = CMe3; CHMe2) featuring a {(Mn4Mn2III)-Mn-II(mu(4)-O)(2)} core of composition [Mn6O2(O2CCMe3)(10)(Me3CCO2H)(3)(EtOH)]center dot(Me3CCO2H) (1), [Mn6O2(O2CCMe3)(10)(Me3CCO2H)(2) (EtOH)(2)]center dot 2(EtOH) (2) and [Mn6O2(O2CCMe3)(10)(Me3CCO2H)(2)(MeOH)(2)]center dot 2(MeOH)H2O (3), and coordination polymers which incorporate such clusters, namely [Mn6O2(O2CCHMe2)(10)(pyz)(MeOH)(2)](n) (4), {[Mn6O2(O2CCHMe2)(10)(pyz)(1.5)(H2O)]center dot 0.5(H2O)}(n) (5), and [Mn6O2(O2CCMe3)(10)(HO2CCMe3)(2)(en)](n) (6), have been synthesized (where pyz = pyrazine, en = ethyl nicotinate). The modification of the cluster surface by a diverse combination of capped or bridging ligands attached to peripheral Mn-II atoms results in discrete clusters with a closed hydrophobic exterior shell in 1 and 2, supramolecular chains built through hydrogen bonded solvent molecule clusters in 3, linear coordination polymers in 4 and 6 or a ladder-like coordination polymer in 5. The H-bonded coordination polymers 4 and 5 form supramolecular layers in crystals.