SYNTHESIS AND CHARACTERIZATION OF DILITHIUM 1,2-DISILAACENAPHTHENEDIIDE

Reaction of ,2-dichloro-1,2-diisopropyl-1,2-disilaacenaphthene (1) wit h excess lithium resulted in formation of the corresponding dilithium 1,2-disilaacenaphthenediide (2) as the 1,2-dilithiodisilane. On treatm ent with methyl iodide and methanol, 2 was converted into the correspo nding 1,2-dimethyl- and 1,2-dihydro-1,2-disilaacenaphthene derivatives , respectively. NMR spectroscopic analysis and theoretical investigati on strongly support the dilithiodisilane structure (2a) in which the n egative charge is localized on the silicon. atom and one lithium atom interacts with one silicon atom, respectively. The measurement of the Si-Li coupling at low temperature shows that a Si-Li bond has a partia l covalency.