On the Polymorphism of 12-Tungstoborate Heteropolyanion: Structure Determination and Its Functionalization with L-proline

A new structure related to previously reported structure of 12-tungstoborate Keggin-type polyoxometalate, K5[BW12O40], was synthesized and its characterization by single crystal X-ray diffraction shows the polymorph structure. Further attempts have been performed to provide three component compounds based on L-proline, lanthanoid cation and K5[BW12O40] (BW12 (II)) under hydrothermal conditions which is rarely reported in hybrid materials rather than other Keggin types. The proposed general structures contain lanthanoid dimers with amino acid bridges and BW12 (II), which characterized by elemental analysis, FT-IR spectroscopy and ICP (Inductively coupled plasma) method. Various types of interactions are established, depending on the POM shape and charge, the amino acid side chain, peptide sequence or protein structure. Experimental conditions such as temperature, acidity, solvent, etc. are also important factors that influence the binding/reactivity of POM with biomolecules, as described recently [13]. This understanding allows the adequate design of the POM-biomolecule couple for tailoring and controlling mechanisms of action such as catalysis, inhibition, and aggregation, or the crystallizing agent.