STRUCTURES OF ORGANONITROGEN LITHIUM COMPOUNDS - RECENT PATTERNS AND PERSPECTIVES IN ORGANOLITHIUM CHEMISTRY

This chapter discusses the current patterns and perspectives in organolithium chemistry, including the structures of organonitrogenlithium (N-Li) compounds. The chapter explains the compounds with N-Li bonds. These are chiefly lithium imides [iminolithiums (RR'C=NLi)n] and their complexes with added Lewis bases (L), and lithium amides [amidolithiums (RR'NLi)n] and their complexes. For the lithium amide species, particularly, only those whose R,R’ groups that do not contain additional functionalities are described—that is, the R,R’ groups remain largely uninvolved with lithium centers. These species are termed “simple” lithium amides. N-Li compounds and, particularly, lithium amides (R2NLi) are widely used both in organic and in organometallic syntheses. For the former, these strong bases are employed as proton abstractors to generate new organolithiums. Although synthetic uses have dominated the interest in N-Li compounds, the chapter focuses on the structures. Most of the physical properties of organolithium compounds (the marked exception being conductance) arise, because of the overall size and shape of the units making up these materials and the nature of the peripheries of these units. The basic structural building block of any organolithium is an ion pair, R–L+. The identities and structures of complexed organolithiums are of particular importance. © 1991 Academic Press Inc.