Polymerizable inorganic–organic hybrid: Syntheses and structures of mono-lacunary Dawson polyoxometalate-based olefin-containing organosilyl derivatives

Three olefin-containing organosilyl derivatives supported on the mono-lacunary Dawson polyoxometalate (POM), [α2-P2W17O61{(RSi)2O}]6− (R = {CH2double bond; length as m-dashC(CH3)COO(CH2)3}, {CH2double bond; length as m-dashCHCOO(CH2)3} and {CH2double bond; length as m-dashCH}), as Me2NH2 salts, which can act as precursors for the immobilization of the POMs in polymer networks, were obtained by the 2:1 molar ratio reaction of the organosilyl precursor RSi(OCH3)3 with K10[α2-P2W17O61] · 19H2O in acidic MeOH/H2O mixed solutions. X-ray crystallography revealed that the two organic chains connected through an –Si–O–Si– bond were grafted onto the mono-lacunary site of the POM. The four-coordination of each Si atom was attained with the bridging oxygen atom, the terminal organic group R in the organosilyl group, and 2 of the 4 oxygen atoms in the mono-lacunary site of the POM.