Bottom-up synthesis of three heterometallic coordination polymers with layered structures constructed from presynthesized [Sb2(tart)2]2− metalloligands

Self-assembly of presynthesized [Sb2(tart)2]2− metalloligand as molecular building block with metal salts affords three unique heterometallic coordination polymers, namely, {[Ln(H2O)6][Sb2(tart)2]}Cl·5H2O (Ln = La (1), Pr (2)) and {[Ba2(H2O)7][Sb2(tart)2]2}·4H2O (3), (tart = tartaric acid). Their structures were determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and TG analyses. Compounds 1 and 2 are isostructural and represent the first examples of lanthanide-organic open frameworks containing [Sb2(tart)2]2− metalloligands. The structures of 1 and 2 contain left-handed and right-handed layer, each built up from the same-handed helical chains. Compound 3 consists of two kinds of arm-shaped chiral layers, which alternately stack in a heterochiral fashion to yield a racemic 3D hydrogen-bonded network with 1D channels along the a axis. To the best of our knowledge, compounds 1–3 are the first 2D chiral layer frameworks constructed from [Sb2(tart)2]2− metalloligands and rare-earth or alkaline-earth metal ions.

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