Efficient Oxidative Desulfurization by Calixarene-Supported “Pineapple-Like” Polyoxometalates

Abstract

Keggin-type polyoxometalates (POMs) are regarded as excellent nanosized inorganic building blocks for the construction of multifunctional hybrids due to their ease of covalent modification. Two new calixarenesupported Keggin-type polyoxometalates [NH 2 Me 2 ] 7 [TM 4 (TC4A)PW 8 O 32 ]• 3CH 3 OH (TM = Co (1), Ni (2), H 4 TC4A = p-tert-butylthiacalix[4]arene) with "pineapple-like" shapes have been synthesized under solvothermal conditions. In these structures, the [TM 4 (TC4A)] building block binds to a rare tetra-lacunary Keggin-type [PW 8 O 32 ] polyanion via W−O−TM bonds. Notably, compounds 1 and 2 serve as recyclable heterogeneous catalysts for the high-efficiency catalytic oxidation of different species of thioethers.

Four Chromic Compounds Constructed from Keggin Polyoxometalates and Viologens with Applications in Ultraviolet, Metal Ion Detection, and Ink-Free Printing

“…Polyoxometalate (POM) is an important branch of the inorganic field, which is a kind of metal oxygen clusters formed by oxygen connection of pretransition metal ions. − Until now, POM has been widely studied as a functional component and applied in many fields such as light, electricity, and magnetism. − Moreover, the surface of POMs is rich in electrons, which can provide electrons easily. Thus, POMs own excellent redox properties, inducing the applications in electrochemistry and catalysis. − Furthermore, the characteristics of rich electrons of POMs can conduce electron transition, which makes POMs act as precursors of chromic materials .…”