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

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 calixarene-supported Keggin-type polyoxometalates [NH2Me2]7[TM4(TC4A)PW8O32]·3CH3OH (TM = Co (1), Ni (2), H4TC4A = p-tert-butylthiacalix[4]arene) with "pineapple-like" shapes have been synthesized under solvothermal conditions. In these structures, the [TM4(TC4A)] building block binds to a rare tetra-lacunary Keggin-type [PW8O32] 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.