= Solution
A dimer compatible with the donor count is an asymmetric \b[Li$_2$O$_2$ ring]. Both phosphoryl oxygen donors bridge both Li centers. The two enamide N donors bind to one Li, whereas both nitrogen donors of a single chelating <TMEDA> bind to the other Li:
$$
\boxed{\mathrm{Li_A:(O_1,O_2,N_{L1},N_{L2}),\qquad
Li_B:(O_1,O_2,N_{T1},N_{T2}).}}
$$
Each Li consequently has exactly two O and two N neighbors, as required. The two donor sets differ chemically, giving \b[two $^7$Li resonances] when the solid-state connectivity is retained in solution. One TMEDA per dimer also matches the stated half equivalent per Li. The hemisolvent stoichiometry must not be drawn as one TMEDA on every Li.
Back to article page
