title: Four alkoxohexavanadate-based Pd-polyoxovanadates as robust heterogeneous catalysts for oxidation of benzyl-alkanes.
abstract: Four 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.
authors: Key Laboratory of Cluster Science Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic, School of Chemistry, Beijing Institute of Technology , Beijing 100081, P.R. China.
authors: Ji-Kun
authors: JK
authors: Li
authors: Xian-Qiang
authors: XQ
authors: Huang
authors: Song
authors: S
authors: Yang
authors: Hong-Wei
authors: HW
authors: Ma
authors: Ying-Nan
authors: YN
authors: Chi
authors: Chang-Wen
authors: CW
authors: Hu