= Solution
\b[C and the dimer of D have the same composition, $\mathrm{Cu_2Li_2(TMP)_4}$, but different metal ordering around an eight-membered metal–nitrogen ring.] C has adjacent Cu sites and adjacent Li sites; in the conventional Gilman dimer D$_2$, Cu and Li alternate around the four metal positions. D is represented by $\mathrm{Li[Cu(TMP)_2]}$ per formula unit. The salt by-product is LiCl.
A TMP anion has formula $\mathrm{C_9H_{18}N}$ and mass about 140.25. Therefore the mass per empirical unit is $2(140.25)+63.55+6.94\simeq350.99$, giving \b[$M_r\simeq702$ for the dimer], consistent with $699\pm5$. A <monomer> would be near 351 and is excluded. In C, inequivalent Cu/Cu, Cu/Li and Li/Li amide surroundings, combined with the constrained TMP orientations, permit the three methyl environments in the observed 1:2:1 integral ratio. D$_2$ has the higher exchange-averaged methyl equivalence needed for one methyl signal. One signal need not imply that all instantaneous solid-state methyl environments are identical.
The remaining formulae follow from atom and charge balance:
$$
\boxed{\mathrm{E=CuTMP,\quad F=Li[Cu(Ph)(TMP)],\quad G=Li_2Cu_2(Ph)(TMP)_3}.}
$$
E can itself aggregate; its formula here specifies the copper-amide unit. F is a mixed organyl/amido <Gilman cuprate>, and G combines one F unit with one D unit. The distinct metal-ordering isomers and these mixed aggregates have experimental precedent.<A new route for the efficient metalation of unfunctionalized aromatics by Andrew J. Peel and others>[2019, metal-exchange isomers and mixed organyl/amido aggregates]{ref}
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