Octahedral Metal Clusters as Building Blocks of Trimetallic.Superexpanded Prussian Blue Analogues

The self-assembly of octahedral metal clusters (diamagnetic [Nb6Cl12(CN)(6)](4-) or paramagnetic [Ta6Cl12(CN)(6)](3-)), [Mn(salen)](+) [salen = N,N'-ethylenebis(salicylidene)iminate] and mononuclear {M'(CN)(x)} polycyanometallates ([Fe(CN)(6)](4-), [Cr(CN)(6)](3-), [Fe(CN)(5)(NO)](2-), or [Ni(CN)(4)](2-)) building blocks results in the formation of a series of six cluster-containing 3D heterotrimetallic frameworks: [H3O](2)[Nb6Cl12(CN)(6)[Mn(salen)](6)Fe(CN)(6)]center dot 3H(2)O (1), [H3O][Nb6Cl12(CN)(6)[Mn(salen)](6)Cr(CN)(6)]center dot 4H(2)O (2), [Nb6Cl12(CN)(6)[Mn(salen)](6)Fe(CN)(5)(NO)]center dot 5H(2)O (3), [Nb6Cl12(CN)(6)[Mn(salen)](6)Ni(CN)(4)]center dot 7H(2)O (4), [H3O][Ta6Cl12(CN)(6)[Mn(salen)](6)Fe(CN)(6)]center dot 4H(2)O (5), and [Ta6Cl12(CN)(6)[Mn(salen)](6)Cr(CN)(6)]center dot 7H(2)O (6). Single-crystal X-ray diffraction analyses show that compounds 1, 2, 5, and 6 have distorted face-centered-cubic frameworks that can be considered as superexpanded Prussian blue analogues built of two different hexacyanometallate nodes and expanded by insertion of the [Mn(salen)](+) complex, while 4 features a quasi-superexpanded Prussian blue framework because the structure is based on the hexacyano metal cluster and disordered tetracyano [Ni(CN)(4)](2-) nodes. The powder X-ray diffraction of 3 indicates that it possesses a quasi-superexpanded Prussian blue framework based on the hexacyano cluster and disordered pentacyano [Fe(CN)(5)(NO)](2-) nodes. Compound 6 is the first compound containing three 3d-3d'-M-6 cluster (4d) spin centers. Magnetic measurements reveal that the overall magnetic nature can be systematically controlled by the choice of the octahedral metal cluster and polycyanometallate nodes. H-2/N-2 adsorption and thermal stability of the compounds were investigated.