1068-69-5Relevant articles and documents
Crystal structures of organometallic compounds of lithium and magnesium containing the bulky ligands C(SiMe3)2(SiMe2X) X=Me, Ph, NMe2, or C5H4N-2
Al-Juaid, Salih S.,Avent, Anthony G.,Eaborn, Colin,El-Hamruni, Salima M.,Hawkes, Simon A.,Hill, Michael S.,Hopman, Martijn,Hitchcock, Peter B.,Smith, J. David
, p. 76 - 86 (2007/10/03)
The complex [Li(TMEDA){C(SiMe3)2SiMe2NMe2}] (1) (TMEDA=N,N,N′,N′-tetramethylethane-1,2,-diamine) was found to crystallise with an internally coordinated structure like that of [Li(THF)2{C(SiMe3)2SiMe2NMe 2}] (THF=tetrahydrfuran). In contrast, the compound with Ph in place of NMe2 crystallised as a dialkyllithate [Li(TMEDA)2][Li{C(SiMe3)2(SiMe 2Ph)}2] (4). The reaction of 4 with MgBr2 gave the doubly bromide-bridged lithium-magnesium complex [Li(TMEDA)(μ-Br)2Mg{C(SiMe3)2(SiMe 2Ph)}(THF)] (6), and that of [Li(THF){C(SiMe3)2(SiMe2C5H 4N-2)}] gave the singly bridged compound [Li(THF)3(μ-Br)MgBr{C(SiMe3)2(SiMe 2C5H4N-2)] (8). The Grignard reagents [Mg{C(SiMe3)3}I(OEt2)]2 (10) and [Mg{C(SiMe3)2 (SiMe2Ph)}I(OEt2)]2 (11) were obtained from the reactions between (Me3Si)3CI and (Me2Ph)(Me3Si)CI, respectively, with magnesium metal and shown to have halide-bridged structures. The unsymmetrical dialkylmagnesium [MgBu{C(SiMe3)2(SiMe2NMe2)}(THF)] (13), was prepared from a mixture of LiBu, 1 and [MgBr2 (OEt2)2].
Properties of Chalcogen-Chalcogen Bonds, XVII. - Di- and Trisulfanes with Sterically Congested Alkyl Substtuents: The First trans-Dialkyldisulfane
Ostrowski, Martin,Jeske, Joerg,Jones, Peter G.,Mont, Wolf-Walther du
, p. 1355 - 1360 (2007/10/02)
Bistrisulfane (1) is obtained from tris(trimethylsilyl)methyllithium and sulfur with subsequent oxidation by oxygen or from tris(trimethylsilyl)methanethiol with sulfur dichloride.The solid trisulfane contains a transoid (helical) C-S-S-S-C backbone without severe distortion from steric strain.Desulfuration of the byproduct bistetrasulfane (2) with mercury provides 1, but further desulfuration of 1 to bisdisulfane (3) has not been achieved. 3 was isolated after oxidation of lithium tris(trimethylsilyl)methanethiolate with bromine. 3 contains a trans-C-S-S-C moiety with an unusually long S-S bond (210-211 pm).The less crowded bis(triphenylmethyl)disulfane (4) contains a "normal" C-S-S-C moiety with anticlinal conformation (torsion angle -110 deg). Key Words: Disulfanes / Trisulfanes / Bond conformations, S-S
ZUR HERSTELLUNG UND REAKTIVITAET VON BIS(TRIMETHYLSILYL)DILITHIOMETHAN
Eikema Hommes, N. J. R. van,Bickelhaupt, F.,Klumpp, G. W.
, p. 5237 - 5240 (2007/10/02)
At -90 deg C in THF or similar media bis(trimethylsilyl)dichloromethane 2 reacts with lithium-4,4'-di-tert-butylbiphenyl (LiDBB) or suspensions of freshly sublimed lithium to give the title compound 1 that can bind two equivalents of various electrophiles. 1 has a great propensity for proton abstraction and it is markedly less reactive towards ethyl iodide than (Me3Si)2EtCLi 6.