Self-assembly morphology and solid state of four organic-polyoxometalate hybrids based on Berberine

Four organic-polyoxometalate hybrids were fabricated by the polyoxoanions and berberine cations from active ingredients of traditional Chinese medicine. Four hybrids were constructed with different topological kernels and number of cations on the surface. The structures of hybrids were characterized and confirmed by elemental analysis, thermogravimetric (TG) analysis, infrared spectra and 1 HNMR. The TG results indicate that hybrids have higher thermal stability than BR. The sites of interaction between BR caitons and POMs based on electrostatic attraction were near the nitrogen atom of isoquinoline skeleton. Self-assembly behaviors and aggregates morphology of four hybrids were obtained by fluorescence microscope, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Hybrids dispersed in methanol show multilayered vesicle structure. Especially, the two hybrids containing Eu show fluorescence property. Relatively, XRD results imply that BR-SiW appears as specially ordered layered structure with cubic symmetry in solid state resulting from aggregates accumulation.