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Synthesis, structural elucidation, and catalytic properties in olefin epoxidation of the polymeric hybrid material [Mo3O9(2-[3(5)-Pyrazolyl]pyridine)]n

DOI: 10.1021/ic403033j DOI Help

Authors: Tatiana Ribau Amarante (University of Aveiro) , Patrícia Neves (University of Aveiro) , Ana C. Gomes (University of Aveiro) , Mariela M. Nolasco (University of Aveiro) , Paulo Ribeiro-Claro (University of Aveiro) , Ana C. Coelho (University of Aveiro) , Anabela A. Valente (University of Aveiro) , Filipe A. Almeida Paz (University of Aveiro) , Stef Smeets (ETH Zürich) , Lynne B. Mccusker (ETH Zürich) , Martyn Pillinger (University of Aveiro) , Isabel S. Gonçalves (University of Aveiro)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Inorganic Chemistry , VOL 53 (5) , PAGES 2652 - 2665

State: Published (Approved)
Published: March 2014
Diamond Proposal Number(s): 8234

Abstract: The reaction of [MoO2Cl2(pzpy)] (1) (pzpy = 2-[3(5)-pyrazolyl]pyridine) with water in an open reflux system (16 h), in a microwave synthesis system (120 °C, 2 h), or in a Teflon-lined stainless steel digestion bomb (100 °C, 19 h) gave the molybdenum oxide/pyrazolylpyridine polymeric hybrid material [Mo3O9(pzpy)]n (2) as a microcrystalline powder in yields of 72–79%. Compound 2 can also be obtained by the hydrothermal reaction of MoO3, pzpy, and H2O at 160 °C for 3 d. Secondary products isolated from the reaction solutions included the salt (pzpyH)2(MoCl4) (3) (pzpyH = 2-[3(5)-pyrazolyl]pyridinium), containing a very rare example of the tetrahedral MoCl42– anion, and the tetranuclear compound [Mo4O12(pzpy)4] (4). Reaction of 2 with excess tert-butylhydroperoxide (TBHP) led to the isolation of the oxodiperoxo complex [MoO(O2)2(pzpy)] (5). Single-crystal X-ray structures of 3 and 5 are described. Fourier transform (FT)-IR and FT Raman spectra for 1, 4, and 5 were assigned based on density functional theory calculations. The structure of 2 was determined from synchrotron powder X-ray diffraction data in combination with other physicochemical information. In 2, a hybrid organic–inorganic one-dimensional (1D) polymer, ∞1[Mo3O9(pzpy)], is formed by the connection of two very distinct components: a double ladder-type inorganic core reminiscent of the crystal structure of MoO3 and 1D chains of corner-sharing distorted {MoO4N2} octahedra. Compound 2 exhibits moderate activity and high selectivity when used as a (pre)catalyst for the epoxidation of cis-cyclooctene with TBHP. Under the reaction conditions used, 2 is poorly soluble and is gradually converted into 5, which is at least partly responsible for the catalytic reaction.

Journal Keywords: Ligands; Molybdenum; Organic reactions; Polymers; Vinyl

Subject Areas: Chemistry, Materials

Instruments: I11-High Resolution Powder Diffraction

Added On: 25/03/2014 14:23

Discipline Tags:

Molecular Complexes Physical Chemistry Catalysis Chemistry Materials Science Inorganic Chemistry Polymer Science

Technical Tags:

Diffraction X-ray Powder Diffraction