Two distinct manganese molybdenum(V) phosphates directed by different organic amines

Abstract

By employing different organic amines as structure-directing agents, two new distinct 3D porous inorganic frameworks based on molybdenum(V) phosphates and Mn II, (H 2en) 2{[Mn(H 2O)] 2[MnMo 12O 24(OH) 6(H 2PO 4) 2(HPO 4) 4(PO 4) 2]}·7H 2O (en = ethylenediamine) (1) and (H 3dien) 2{[Mn(H 3O) 2][Mn 3Mo 12O 24(OH) 6(HPO 4) 2(PO 4) 6]}·5H 2O (dien = diethylenetriamine) (2), have been hydrothermally synthesized, and characterized by routine physical methods. In compound 1, Mn II all adopt octahedral coordination mode and each sandwich cluster Mn[Mo 6P 4O 31] 2 (abbreviated as Mn[Mo 6P 4] 2) acts as an octa-dentate ligand linking eight Mn II, which result in a 3D inorganic (4, 8)-connected framework with the (4 6)(4 10·6 12·8 6) topology. Compound 2 shows a 3D (4, 10)-connected framework with the (3 1·4 4·6 1)(3 4·4 9·5 7·6 17·7 4·8 4) topology, in which Mn II ions exhibit both tetrahedral and octahedral coordination modes, and each Mn[Mo 6P 4] 2 links ten Mn II. Interestingly, there exist channels along the a and b axes in 1, while along the a and c axes in 2. The differences between the two compounds should be ascribed to the distinctions of the organic amines. Primary de-/rehydration behaviors and electrochemistry properties have also been studied for the two compounds.