Syntheses, structures and properties of two new organic-inorganic hybrid materials based on ε-Zn Keggin units {ε-PMoV8MoVI4O40-x(OH)xZn4}

Two novel organic-inorganic hybrids, Na[(PMo8Mo4O38)-Mo-V-O-VI(OH)(2)Zn-4][pyim](2)center dot 1.5H(2)O [epsilon(pyim)(2)] (pyim = 2-(2-pyridyl)-imidazole) and [(PMo8Mo4O37)-Mo-V-O-VI(OH)(3)Zn-4](2)[pyim](6)center dot 4H(2)O [epsilon(2)(pyim)(6)], based on epsilon-Zn Keggin units {epsilon-(PMo8Mo4O40-x)-Mo-V-O-VI(OH)(x)Zn-4}, have been successfully synthesized under hydrothermal conditions by controlling the pH values. Structural analysis indicates that the framework of epsilon(pyim)(2) is a 1D chain constructed by monomeric epsilon-Zn units modified by pyim ligands, while epsilon(2)(pyim)(6) is an isolated structural compound with dimeric epsilon-Zn units modified by pyim ligands. This is the first isolated structure of the epsilon-Keggin POMs system. The luminescent and electrochemical properties of epsilon(pyim)(2) and e(2)(pyim)(6) were investigated. epsilon(2)(pyim)(6) also shows high catalytic activity for the esterification of phosphoric acid with equimolar lauryl alcohol to monoalkyl phosphate ester (MAP).