Synthesis, structure, and characteristics of a hexa-Ti-oxo-cluster-added Keggin-type polyoxometalate

Abstract

An acentric hexa-Ti-oxo-cluster-added trimeric phosphotungstate, [H2N(CH3)2]3H12[Ti6O6(A-α-1,2-PW10O37)3]∙12 H2O (1), was synthesized by reacting trivacant polyoxometalate (POM) fragments with Ti4+ ions under hydrothermal conditions and characterized via single-crystal/powder X-ray diffraction, solid UV–vis and IR spectroscopies, and thermogravimetric analysis. The polyoxoanion of 1 is constituted by three Ti2O3(A-α-1,2-PW10O37) subunits linked through Ti–O–Ti bonds, forming a ring-shaped configuration. Furthermore, 1 exhibits a second-harmonic generation response about 0.6 times that of KH2PO4, which paves the way toward the development of Ti-added POMs in the field of nonlinear optical materials.

Keywords

• ti-oxo cluster
• addition reaction
• hydrothermal synthesis
• nonlinear optics