Synthesis and crystal structures of three thioether functionalized lithium silylamides

Abstract

A series of three lithium silylamides Li2Me2Si(NC6H4-2-SR)2 (R=Me, Ph, tBu) were prepared from the reaction of the corresponding silylamines Me2Si(NH-C6H4-2-SR)2 with n-butyl lithium. X-ray single crystal structure analyses revealed the formation of dimers [Li4{Me2Si(NC6H4-2-SR)2}2] with Si2N4Li4 hetero-adamantane cores. Recrystallisation of [Li4{Me2Si(NC6H4-2-SMe)2}2] and [Li4{Me2Si(NC6H4-2-SPh)2}2] from diethyl ether led to the formation of the adducts [Li4(Et2O)2{Me2Si(NC6H4-2-SMe)2}2] and [Li4(Et2O){Me2Si(NC6H4-2-SPh)2}2]. In the case of the SMe derivative the addition of two diethyl ether molecules led to a rearrangement of the Si2N4Li4 core to give a double decker structure and in contrast the hetero adamantane structure is retained in the diethyl ether adduct of the SPh derivative.