Synthesis and structural studies of an (8-quinolyl)amido-lithium complex and its reaction with dimethylsilicone

Treatment of 8-aminoquinoline (AQH2) with nBuLi in diethyl ether affords {[(AQH)2]Li2(OEt2)}2 (1). Compound 1 reacts with dimethylsilicone to yield the lithiated SiMe2-bridged complex, {[(AQ)2SiMe2]Li2(OEt2)}2 (2). Compound 2 has also been synthesised by treating 1 with dichlorodimethylsilane affording {[(AQH)2SiMe2] (3), followed by dilithiation. All complexes were characterised by spectroscopic and X-ray crystallographic methods. The X-ray structure of 1 reveals a tetranuclear centrosymmetric dimeric structure with a Li4N4 step-ladder arrangement. Compound 2 is tetranuclear with an eight-membered Li4N4 ring with ligands straddling Li atoms at opposing corners of the ring. Compound 3 has a SiMe2 group bridging two 8-amidoquinoline functionalities.