Isomerism And Oxidation Catalytic Properties Of Wheel-Type Polyoxometalates Based On Hexavacant Dawson Structure

In this paper, hexavacant Dawson structure isomerism has been explored based onsaturated Dawson strecture by identifing and analyzing its IR and NMR spectroscopy. Inaddition, further discussion about isomerism of two wheel-type {P8W48} polyoxometalatesbased on {P2W12} modified by transition metal (Zn2+) is in progress. At the same time, make acomprehensive analysis of relevant literatures on their IR spectroscopy, NMR spectroscopy,crystal structures and biochemistry, for speculating the biochemical reasons of the formationof the structure. Moreover, three tungstophosphates by introducing metal ions and group(Na+、K+and TBA+) into the skeletons of {P8W48} polyoxoanions have been obtained. Allcompounds have been characterized by single-crystal X-ray diffraction, IR spectroscopy,elemental analysis. Their catalytic oxidation of cyclohexanol to cyclohexanone have beenstudied. Experimental data show that in three wheel-type {P8W48} compounds, along with thecationic radius increases gradually, compounds solubility also increases accordingly, and thecatalytic efficiency of the catalytic oxidation of cyclohexanol to cyclohexanone also increasedin turn. While TBAItungstophosphate not only can be a homogeneous catalyst but also be as aheterogeneous catalyst. In the three tungstophosphates with wheel-type structure, compoundTBAIcatalytic efficiency is highest. These three compounds have been characterized by IRspectroscopy after three circulations of oxidation catalytic reaction. Analysis of the spectra,we know the basic skeleton of the wheel-type {P8W48} unchanged. Experimental datasconfirm that the tungstophosphates can be recycled and act as a environmental friendlycatalyst with broad prospect.1. Separation of saturated Dawson structure isomers, analysis the isomerism by IR andNMR spectroscopy of basic building block {P2W12}. on this basis, isomerism of twowheel-type {P8W48} polyoxometalates based on {P2W12} modified by transition metal (Zn2+)is in progress.2. Three wheel type tungstophosphates modified by transition metal ions (Na+, K+andTBA+) based on {P8W48} precursor have been synthesized, at the same time discuss thecatalytic performance of catalytic oxidation of cyclohexanol to cyclohexanone of thesecompounds.