First Tungstoantimonate-Based Transition-Metal–Lanthanide Heterometallic Hybrids Functionalized by Amino Acid Ligands

Abstract

By the routine aqueous solution method, a series of transition-metal–lanthanide heterometallic tungstoantimonates [Ln(H2O)8]2[Fe4(H2O)8(thr)2][B-β-SbW9O33]2·22H2O [Ln = PrIII (1), NdIII (2), SmIII (3), EuIII (4), GdIII (5), DyIII (6), LuIII (7), thr = threonine] were prepared and structurally characterized by multiple testing techniques. The common structural characteristic of 1–7 is that they are isomorphous and all consist of a [Fe4(H2O)8(thr)2(B-β-SbW9O33)2]6– subunit with two supporting [Ln(H2O)8]3+ cations on both sides. It should be pointed out that two thr ligands in the [Fe4(H2O)8(thr)2(B-β-SbW9O33)2]6– subunit substitute for two water ligands in the classical [Fe4(H2O)10(B-β-SbW9O33)2]6– polyoxoanion. As far as we know, 1–7 represents the first organic–inorganic tungstoantimonate hybrids consisting of transition metal and lanthanide cations and amino acid components. The fluorescence behavior of 4 has been measured and manifests the remarkable fluorescence feature resulting from the emission sign...