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Download fileFour Alkoxohexavanadate-Based Pd-Polyoxovanadates as Robust Heterogeneous Catalysts for Oxidation of Benzyl-Alkanes
journal contribution
posted on 2015-02-16, 00:00 authored by Ji-Kun Li, Xian-Qiang Huang, Song Yang, Hong-Wei Ma, Ying-Nan Chi, Chang-Wen HuFour alkoxohexavanadate-based Pd-POVs
[Pd(dpa)(acac)]2[V6O13(OMe)6] (1), [Pd(dpa)(acac)]2[V6O11(OMe)8] (2), [Pd(dpa)(acac)]2[V6O11(OMe)8]·H2O (3), and [Pd(DMAP)2(acac)]2[V6O11(OMe)8]·H2O (4) (POV = polyoxovanadate; dpa = 2,2′-dipyridine
amine; DMAP = 4-dimethylaminopyridine; acac = acetylacetone anion)
have been synthesized and fully characterized by single crystal X-ray
diffraction and powder X-ray diffraction analyses, Fourier transform
infrared spectroscopy, element analyses, and X-ray photoelectron spectroscopy.
In 1–4, Pd complexes and hexavanadate
anions are assembled through electrostatic interactions. Interestingly,
the [V6O11(OMe)8]2– cores in 2 and 3 are a pair of isomers
that can be isolated by controlling crystallization temperature. Moreover,
to the best of our knowledge, the {V6} core in 3 represents
a new octamethoxyhexavanadates cluster. It is notable that compounds 1–4 exhibit excellent heterogeneous catalytic
performance in the oxidation of benzyl-alkanes with t-butylhydroperoxide as oxidant. Among them, the catalytic activity
of 1 (conv. and selec. up to 99%, respectively) outperforms
others and can be reused without losing its activity.
