Untersuchungen zur Carbeninsertion in Al-Al-, Ga-Ga- und In-In-Bindungen
摘要:
Tetrakis[bis(trimethylsilyl)methyl] dialane(4) 1 reacts with methylthiomethyl lithium LiCH2SMe by the formation of lithium thiomethanolate LiSMe and the insertion of the remaining carbene CH2 into its Al-Al single bond. A chelating Lewis acid is formed exhibiting a central R2Al-CH2-AIR(2) group with two coordinatively unsaturated Al atoms, which coordinate the thiomethanolate anion by Al-S bonds. The product (mu-methylene) (mu-thiomethanolato)bis{bis[bis(trimethylsilyl)methyl]aluminate} (4) was characterized by a crystal structure determination and has a strongly folded Al2CS heterocycle in the molecular core. In contrast,;he corresponding compounds with Ga-Ga or In-In bonds show on treatment with methylthiomethyl lithium a fragmentation, and the carbene intermediate could not be detected in both isolated products, which were identified as [R2E(CH2SMe)(2)][Li(TMEDA)] (E = Ga: 5; E = In: 6) and LiCH(SiMe3)(2) probably formed by a metal exchange reaction.