Homochiral frameworks derived from magnesium, zinc and copper salts of l-tartaric acid

Five metal-organic frameworks derived from l-tartarate (l-tart=C₄H₄O₆) and the divalent metal ions magnesium, zinc or copper have been prepared and structurally characterized. The frameworks were prepared from the reaction of potassium l-tartrate [KC₄H₅O₆] with the appropriate metal salt in water solutions. The magnesium compound [Mg(l-tart)(H₂O)⊃1.5H₂O], 1, crystallizes as a two-dimensional 6³ sheet structure. The addition of the divergent linker molecules 4,4′-bipyridine (bipy) or trans-1,2-bispyridylethylene (bpe) to systems involving Zn²⁺ and Cu²⁺ results in the formation of the homochiral three-dimensional structures [Zn₂(l-tart)2(biyp)(H₂O)⊃5.25H₂O], 2, [Cu(l-tart)(bipy)⊃2.33H₂O], 3, and [Cu(l-tart)(bpe)⊃8H₂O], 5. Removal of solvent water molecules from 3 resulted in [Cu(l-tart)(bipy)⊃0.2H₂O], 4. Similar experiments on 2 and 5 resulted in breakdown of the frameworks, illustrating the dependence of the stability of these structures on the guest water molecules. This study reports the structures of two new topological types of binodal nets.