Synthesis and structure of a novel lithium gallosiloxane containing a Ga4Si4O8 macrocycle analogous to the S8R building unit of zeolites

Abstract

The reaction of LiGaMe4 with diphenysilanediol in THF at 50 degreesC leads to the formation of the title gallosiloxane Li-2(Li(THF)(2))(2)[Ph2SiO2GaMe2](2)[Ph2SiO2GaMe(OH)](2). 2THF (1), which is made up of a central tetraanionic G alpha 4Si4O8 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 true 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.