Isolation and solution structures of {PhCH2NLiCH2CH2NMe2} n and of the totally rigid dilithium compound, {o-LiC6H4CH2NLiCH2CH2NMe2} n ; evidence for Li…o-HC interactions

Monolithiation of N′-benzyl-N,N-dimethylethylenediamine produces {PhCH2NLiCH2CH2NMe2} n , believed to have a trimeric (NLi)3 ring structure in arene solutions. Lithium…o-HC interactions are implicated within this monolithiated compound since further lithiation proceeds smoothly and regiospecifically to give {o-LiC6H4CH2NLiCH2CH2NMe2} n . High-field 1H and 7Li NMR spectra show that this dilithium derivative (probably tetrameric) has a totally rigid solution structure brought about by intra- and inter-molecular N → Li coordinations