Polyoxovanadate catalysts for oxidation of 1-phenyl ethanol: from the discrete [V4O12]4− and [V10O28]6− anions to the anionic [V6O17]n4n− coordination polymer

Abstract

Three polyoxovanadate-based hybrids {[Ru(phen)₃]₂[V₄O₁₂]}·13H₂O (1), [Ru(phen)₃]₂[V₁₀O₂₈]·15H₂O (2), and [Ru(phen)₃]₂[V₆O₁₇]Cl·11H₂O (3) (phen = 1,10-phenanthroline) were prepared under hydrothermal conditions and characterized by electron paramagnetic resonance (EPR) spectroscopy, infrared spectroscopy (IR), powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis, X-ray photoelectron spectroscopy (XPS), and single crystal X-ray diffraction analysis. Although the structures of both the cyclic vanadate [V₄O₁₂]⁴⁻ and the [V₁₀O₂₈]⁶⁻ anions are well-known, interestingly, a novel 1-dimensional (1-D) coordination polymer [V₆O₁₇]_n⁴ⁿ⁻ anion was constructed from tetranuclear [V₄O₁₂]⁴⁻ and dinuclear [V₂O₇]⁴⁻ building blocks, which were linked alternately through corner-shared oxygen atoms. Furthermore, the negative charges of polyoxovanadate [V₄O₁₂]⁴⁻, [V₁₀O₂₈]⁶⁻ and [V₆O₁₇]⁴⁻ anions were balanced by two [Ru(phen)₃]^2+/3+ complex cations. The catalytic properties of compounds 1–3 for the oxidation of 1-phenyl ethanol by tert-butyl hydroperoxide (TBHP) were investigated, and the results demonstrated that 1 and 3 exhibited excellent catalytic activities for the oxidation of 1-phenyl ethanol under mild catalytic conditions.