Ce(iii)-Containing tungstotellurate(vi) with a sandwich structure: an efficient Lewis acid–base catalyst for the condensation cyclization of 1,3-diketones with hydrazines/hydrazides or diamines

Abstract

A new Ce³⁺ modified Dawson-like polyoxometalate cluster (C₂H₈N)₁₂Na₂[H₁₀{Ce(H₂O)₅}₂(Te₂W₃₇O₁₃₂)]·39H₂O was synthesized using pH and temperature-controlled one-pot strategy. The compound was characterized by single-crystal X-ray structure analysis, IR spectroscopy, thermogravimetric (TG) analysis, X-ray photoelectron spectroscopy (XPS), and electrospray ionization mass spectrometry (ESI-MS). Single-crystal X-ray structure analysis revealed that there was a new {Te₂W₃₇O₁₃₂} structure and two Ce³⁺ in this compound. Moreover, it is notable that this compound presents excellent Lewis acid- and Lewis base activities in the condensation cyclization of 1,3-diketones with hydrazines/hydrazides or diamines. All the desired products were obtained in moderate to good yields (up to 99%) and with a high turnover number (up to 4347).