Synthesis and structural characterisation of the trinuclear barium disiloxanes [Ba3(OSiPh2OSiPh2O)3(tetraglyme)2] and [Ba3(OSiPh2OSiPh2O)3(hmpa)5(H2O)], containing an unusual Ba3O7 core [tetraglyme = Me(OCH2CH2)4OMe; hmpa =(Me2N)3PO]

Abstract

Barium granules react with diphenylsilanediol in a mixed ammonia–toluene solution at –40 °C to yield [Ba(OSiPh₂OSiPh₂O)(H₂O)(NH₃)_0.33]1, addition of either tetraglyme or hexamethylphosphoramide (hmpa) produces [Ba₃(OSiPh₂OSiPh₂O)₃(tetraglyme)₂]2 and [Ba₃(OSiPh₂OSiPh₂O)₃(hmpa)₅(H₂O)]3, respectively; complexes 2 and 3 are the first X-ray structurally characterised barium disiloxanes and contain an unusual trinuclear array of Ba cations incorporating an identical Ba₃O₇ core.