Figure 1.

(a) Subcomponent self-assembly of M^I₁₂L₄ cages 1 and 2. Externally coordinated acetonitrile molecules are omitted for clarity. (b) ¹H and DOSY NMR spectra of 1. The signal for H₆ is not observed at 298 K (see Supporting Information Section 1.2).¹⁹ (c) Crystal structure of 1 with inset showing one of its dicopper(I) vertices. Disorder, anions, solvent of crystallization, and hydrogen atoms are omitted for clarity. (d) Illustration of the head-to-head vertex geometry observed for 1 and the alternative head-to-tail arrangement previously observed in analogous dinuclear Cu^I complexes.¹⁵