A family of layered chiral porous magnets exhibiting tunable ordering temperatures

A simple change of the substituents in the bridging ligand allows tuning of the ordering temperatures, T_c, in the new family of layered chiral magnets A[M^IIM^III(X₂An)₃]·G (A = [(H₃O)(phz)₃]⁺ (phz = phenazine) or NBu₄⁺; X₂An^2- = C₆O ₄X₂^2- = 2,5-dihydroxy-1,4-benzoquinone derivative dianion, with M^III = Cr, Fe; M^II = Mn, Fe, Co, etc.; X = Cl, Br, I, H; G = water or acetone). Depending on the nature of X, an increase in T_c from ca. 5.5 to 6.3, 8.2, and 11.0 K (for X = Cl, Br, I, and H, respectively) is observed in the MnCr derivative. Furthermore, the presence of the chiral cation [(H₃O)(phz)₃]⁺, formed by the association of a hydronium ion with three phenazine molecules, leads to a chiral structure where the Δ-[(H₃O)(phz) ₃]⁺ cations are always located below the Δ-[Cr(Cl₂An)₃]^3- centers, leading to a very unusual localization of both kinds of metals (Cr and Mn) and to an eclipsed disposition of the layers. This eclipsed disposition generates hexagonal channels with a void volume of ca. 20% where guest molecules (acetone and water) can be reversibly absorbed. Here we present the structural and magnetic characterization of this new family of anilato-based molecular magnets.