6533b825fe1ef96bd12826f3

RESEARCH PRODUCT

Solvent-modulated structures in anilato-based 2D coordination polymers

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Abstract This work highlights the key role of the solvents in the structures of the series of 2D compounds [Ln2(C6O4Br2)3·(Solvent)n]·G (G = Guest). This study is based on the affinity and ability of these solvents to coordinate to lanthanides and on their possibility to act as solvation molecules. For this purpose here we focus on the Er(III) ion and on the bromanilato bridging ligand ([C6O4Br2]2− = dianion of 3,6-dibromo-2,5-dihydroxy-1,4-benzoquinone) and we play with three solvents: H2O, DMSO (dimethylsulfoxide) and DMF (dimethylformamide). Here we report the synthesis, crystal structure and magnetic characterization of compounds [Er2(C6O4Br2)3(H2O)6]·12H2O (1), [Er2(C6O4Br2)3(DMSO)4]·2DMSO·2H2O (2) and [Er2(C6O4Br2)3(DMF)6] (3). We show the key role played by the shape and size of the three solvents in (i) the coordination number and geometry of the metal ion, (ii) the distortion of the hexagonal cavities of these (6,3)-2D lattices, (iii) the presence/absence of porosity in these hexagonal cavities and (iv) the interlayer separation. The magnetic characterization of the three compounds show the expected behavior for almost isolated Er(III) ions since the bridging (C6O4Br2)2− ligands give rise to very weak (if any) antiferromagnetic couplings. Finally we also show that this study can be extended to other lanthanide with other anilato-based ligands [C6O4X2]2− (X = Cl, Br, NO2, H,…) and using other solvents.