Pentacoordinate spirosilicate anion, bis(2,2′-biphenyldiyl)methylsilicate, synthesized by the lithium cleavage of dimethoxyethane

摘要: The reaction of spirobisilafluorene (1) with lithium in dimethoxyethane produces 1-methyl-spirobisilafluorenide (2), a stable pentacoordinate silicon compound five carbon ligands, and 2-methoxyethoxide, which was identified by trapping Ph3SiCl to give Ph3Si-OCH2CH2OCH3 (4). X-ray crystal structure 2 shows that the geometry at is an idealized trigonal bipyramid, slightly distorted toward square pyramid. Methanolysis cleaves Si-aryl bond producing methyl biphenylsilafluorene, 3. Crystal structures are reported for 3 4.