Synthesis, Structural Elucidation, and Application of a Pyrazolylpyridine鈥揗olybdenum Oxide Composite as a Heterogeneous Catalyst for Olefin Epoxidation

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• 作者：S贸nia Figueiredo ; Ana C. Gomes ; Patr铆cia Neves ; Tatiana R. Amarante ; Filipe A. Almeida Paz ; Ros谩rio Soares ; Andr茅 D. Lopes ; Anabela A. Valente ; Martyn Pillinger ; Isabel S. Gon莽alves
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：August 6, 2012
• 年：2012
• 卷：51
• 期：15
• 页码：8629-8635
• 全文大小：375K
• 年卷期：v.51,no.15(August 6, 2012)
• ISSN：1520-510X

文摘

The reaction of [MoO₂Cl₂(pypzEA)] (1) (pypzEA = ethyl[3-(pyridin-2-yl)-1H-pyrazol-1-yl]acetate) with water in a Teflon-lined stainless steel autoclave (100 掳C) or in an open reflux system leads to the isolation of the molybdenum oxide/pyrazolylpyridine composite material [Mo₂O₆(HpypzA)] (2; HpypzA = [3-(pyridinium-2-yl)-1H-pyrazol-1-yl]acetate). The solid state structure of 2 was solved through single crystal and powder X-ray diffraction analyses in conjunction with information derived from FT-IR and ¹³C CP MAS NMR spectroscopies and elemental analyses. In the asymmetric unit of 2, two crystallographically distinct Mo⁶⁺ centers are bridged by a syn,syn-carboxylate group of HpypzA. The periodic repetition of these units along the a axis of the unit cell leads to the formation of a one-dimensional composite polymer, _{鈭?/sub>¹[Mo2O6(HpypzA)]. The outstretched pyrazolylpyridine groups of adjacent polymers interdigitate to form a zipper-like motif, generating strong onset 蟺鈥撓€ contacts between adjacent rings of coordinated HpypzA molecules. The composite oxide 2 is a stable heterogeneous catalyst for liquid-phase olefin epoxidation.}