Synthesis and structural characterization of a novel organic-inorganic supermoleculer of [Fe^II(Phen)₃]L₂ · 2H₂O complex

A new Keggin-type silicotungstate anion-supported organic-inorganic hybrid transition metal complex, [Zn(Bipy)(3)](1.5)[SiW12O40Zn(Bipy)(2)(OH)] center dot 0.25H(2)O (I) (Bipy = 2,2'-bipyridine), has been synthesized by the hydrothermal method and characterized by elemental analysis, IR, UV, and EPR spectra, TG-DTA analysis, and single crystal X-ray diffraction. The structural analysis indicates that each structural unit of I consists of one [SiW12O40Zn(Bipy)(2)(OH)](3-) heteropolyanion, one and a half isolated [Zn(Bipy)(3)](2+) cations, and a quarter of crystal water molecule. The [Zn(Bipy)(2)(OH)](+) unit is covalently bonded to one Keggin polyoxoanion [SiW12O40](4-) in the [SiW12O40Zn(Bipy)(2)(OH)](3-) cluster. The EPR spectrum indicates the existence of Zn2+ with the high-spin state, and TG-DTA analysis exhibits that I has two steps of weight loss and the polyoxoanion framework is collapsed at 618A degrees C.