Synthesis and Structure of a Novel Lithium Gallosiloxane Containing a Ga4Si4O8 Macrocycle Analogous to the S8R Building Unit of Zeolites

The reaction of LiGaMe 4 with diphenysilanediol in THF at 50 °C leads to the formation of the title gallosiloxane Li 2 (Li(THF) 2 ) 2 [Ph 2 SiO 2 GaMe 2 ] 2 [Ph 2 SiO 2 GaMe(OH)] 2 ·2THF ( 1 ), which is made up of a central tetraanionic Ga 4 Si 4 O 8 16-membered macrocyclic core. The cavity that is created by this tetraanionic gallosiloxane ring and also the presence of two Ga−OH groups pointing toward the center of the macrocyclic ring facilitate the entrapment of two lithium cations in the core through two Li−O(siloxide) and two Li−OH(Ga) linkages. The other two lithium ions are located at the periphery and are bound to the gallosiloxane ring through the Li−O(Si) linkages. Compound 1 represents the first organic-soluble molecular model compound for the S8R secondary building unit of several gallo- and aluminosilicates.