Synthesis and Structural Characterization of a γ-Keggin-Type Dimeric Silicotungstate with a Bis(μ-hydroxo) Dizirconium Core [(γ-SiW10O36)2Zr2(μ-OH)2]10-

A novel dinuclear zirconium sandwich-type silicotungstate cluster of [(gamma-SiW(10)O(36))(2)Zr(2)(mu-OH)(2)](10-) (1) was synthesized by the reaction of a divacant lacunary gamma-Keggin silicotungstate [gamma-SiW(10)O(36)](8-) with ZrOCl(2).8H(2)O. The anion consisted of two [gamma-SiW(10)O(36)](8-) units sandwiching a diamond Zr(2)(mu-OH)(2) core, and each zirconium atom in 1 was six-coordinated to two mu-OH ligands and four oxygen atoms of two [gamma-SiW(10)O(36)](8-) units. The Zr(2)(mu-OH)(2) core in 1 reacted with methanol to give the corresponding monomethoxo derivative [(gamma-SiW(10)O(36))(2)Zr(2)(mu-OH)(mu-OCH(3))](10-) (2).