N,N-Dilithioarylamines as New Building Blocks in Amide Chemistry; the Structure of a Carbanion-Stabilized [C2N5Li10]2− Cluster

2-Biphenylamine reacts with (dimethylamino)trimethylstannane in a 2:1 molar ratio, undergoing transamination to the distannylamine 1a. The extremely air and moisture sensitive (2-biphenyl)-N,N-dilithium amide 2a is obtained by the stannazane cleavage reaction of 1a with nBuLi in MeOtBu. Compound 2a is the first example of a highly reactive, doubly metallated amine that can be used as a precursor in inorganic synthesis under fairly mild conditions. For example, both lithium atoms can be substituted by boryl or silyl groups, which cannot be introduced using other routes. Amide 2a crystallizes as a cluster containing five RNLi2 units, and is unexpectedly stabilized by two methanide anions. When the methanide ions are included, the lattice of the central C2N4Li8 unit represents a section of the antiisomorphic lattice of the CaF2-type. DFT (B3LYP) calculations and population analysis (NBO) have been carried out to get further insights into the thermodynamics of several dilithioamines (RNLi2)n (R = H, CH3, Ph; n = 1−6). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)