Cu-3(BTC)(2) catalyzed dehydrogenative coupling of dimethylphenylsilane with phenol and homocoupling of dimethylphenylsilane to disiloxane

摘要

Cu-3(BTC)(2) (BTC: 1,3,5-benzenetricarboxylic acid) showed to be an efficient and reusable heterogeneous solid catalyst for the formation of Si-O bond through dehydrogenative coupling of dimethylphenylsilane (1) with phenol under mild reaction conditions. It is observed that Fe(BTC), MIL-101(Cr) and UiO-66(Zr) are not able to promote this cross coupling between 1 and phenol. Cu-3(BTC)(2) exhibits higher stability and activity compared to other MOFs studied here. Furthermore, Cu-3(BTC)(2) is reused for three consecutive cycles with a slight decay in its activity. Comparison of the powder XRD patterns of the fresh with three times used Cu-3(BTC)(2) shored no significant difference in the crystalline structure, thus, indicating the catalyst stability under the optimized reaction conditions. Furthermore, EPR, FT-IR and SEM images of the fresh and reused Cu-3(BTC)(2) did not show any change in the oxidation state of copper or structural morphology. Also, no leaching of copper is detected under optimized reaction conditions. In addition, Cu-3(BTC)(2) showed higher activity compared to Pt, Pd, Au and Cu supported on active carbon as heterogeneous catalysts in the synthesis of disiloxane from 1 through Si-H activation. (C) 2016 Elsevier Inc. All rights reserved.