Synthesis, Crystal Structure, and Biological Activity of Two Complexes based on 5-hydroxy-4-methoxyisoflavone-3-sulfonate

Two metal complexes [Mn(H2O)(6)(C16H11O7S)(2)]2H(2)O (I) and Al(H2O)(3)(C16H11O7S) 2H(2)O (II) were synthesized by reaction of the sodium 5-hydroxy-4-methoxyisoflavone-3-sulfonate (C16H11O7SNa) with MnSO4 4H(2)O or Al(NO3)(2) 6H(2)O, respectively. Complex I and II were characterized by the single crystal X-ray diffraction (CIF files CCDC nos. 1563980 (I), 1563981 (II)), IR spectroscopy, thermogravimetric and elemental analysis. For complex I, the coordination number of Mn(II) is 6 and the coordinated atoms are all oxygen atoms from six H2O molecules. For complex II, the coordination number of Al(III) is 4, and coordinated atoms come not only from three water molecules but also the sulfo-group. Furthermore, I and II have hydrogen bonding and <bold> stacking supramolecular interactions</bold>. Hydrogen bonding forms a hydrophilic region, <bold> stacking forms a hydrophobic region</bold>. The sulfo-group is a vital bridge between the hydrophilic region and the hydrophobic region, which improves the water-soluble ability and prompts the versatile assembly of pallidiflorin with metal ion. In addition, the preliminary biological test showed that I, II had antimicrobial activities.