Structure, slow magnetic relaxation behavior and bacteriostatic activity of a novel Dy₄ cluster

A novel tetranuclear Dy(III)-based cluster, namely [Dy-4(CO3)L-4 (acac)(2)(CH3OH)(2)(CH2OH)(2)]center dot 2CH(3)OH (1) (where H2L is 2-(hydroxyimino)-2-[(5-bromo-2-hydroxyphenyl)methylene]hydrazide and Hacac is acetylacetonate) has been constructed by employing a newly prepared Schiff based ligand H2L. X-ray diffraction data reveal that 1 is mainly consist of a rhombic Dy-4 core, in which the four Dy3+ ions are bridged by six mu-O atoms from four ligands H2L and two mu(2)-O atoms from the in situ formed CO32- via spontaneous fixation of atmospheric CO2. The crystal structure of 1 possesses two distinct Dy3+ ions coordination center, and the nine-coordinated Dy7(3+) ions center presenting a distorted spherical capped square antiprism geometry and eight-coordinated Dy4(3+) ions center presenting a distorted triangular dodecahedron geometry. Magnetic study indicates that 1 displays slow magnetic relaxation behavior under H-dc = 0 Oe filed. Furthermore, the fluorescence property investigation reveals that 1 shows DyIII characteristic emission peaks. Moreover, the antibacterial activity and mechanism of 1 have been systemically studied, and cluster 1 possesses well antibacterial activity on five common bacteria (Escherichia coli, Staphylococcus aureus, Staphylococcus albus, Bacillus subtilis, and Micrococcus luteus). In addition, the interaction between 1 and DNA have been studied.