No abstract

The first known trimercury and cyclic tetramercury organosilicon compounds containing the -(Hg-R 2 Si-Hg)-fragment, (t-BuHgSiR 2 ) 2 Hg [R ) i-Pr 3 Si (3a), R ) t-Bu 2 MeSi (3b)] and [(i-Pr 3 Si) 2 SiHg] 4 (6), were synthesized and characterized. Reactions of the corresponding H 2 SiR 2 silanes with t-Bu 2 Hg yielded 3a and 3b. 6 was obtained from a hexane solution of 3a that was stored at room temperature for 6 months. The molecular structures of 3a, 3b, and 6 were determined by X-ray analysis. Photolysis and thermolysis of 3 leads to formation of mercury-substituted silyl radicals (previously unknown). Their structure was confirmed by a detailed EPR study and by trapping with 2,2,6,6,-tetramethyl-1-piperidinyloxyl (TEMPO) radical. A radical mechanism for the formation of 3 was evidenced by the observation of EPR signals in the reaction mixture of Hg-substituted silyl radicals.

Ein Triplett‐Silyldiradikal 2 und eine Familie von Silylradikalen, in denen das Silylradikalzentrum Teil eines Silyllithiumaggregats ist, entstehen photochemisch aus dem gem‐Dilithiosilan [(R2SiLi2)(R2HSiLi)2] (1, siehe Schema; R′: unbekannt). Das EPR‐Spektrum von 2 besteht aus vier Seitenbanden, die von ΔM=1‐Übergängen herrühren, und einem Signal bei halbem Feld, das von den verbotenen ΔM=2‐Übergängen stammt.

The title compound, Li+·C24BF20−·2C6H6, crystallizes as centrosymmetric dimers, with two η6‐coordinated and two uncoordinated mol­ecules of benzene per dimer. There are two crystallographically independent dimers.

An anionic dilithium compound: The dianion [(R2Si)3Li4]2− (R=tBu2MeSi) as salt 2 was synthesized as the first of its kind by dissolving 1 in THF. The structure of 2 was solved by X‐ray crystallography and studied by solid‐state and solution NMR spectroscopy. Compound 2 reacts as a dilithiosilane.