When dissolved in methanol at 5 μM concentration, compounds 11 (a), 12 (b), and 8 (c) yield simple spectra (dotted lines) consistent with monomeric structure (M). In assembly buffer (solid lines), increasing concentrations of compounds 11 and 12, but not 8, revealed the presence of both monomeric (M) and aggregated (D) species, with the latter more pronounced at high concentrations. These data suggest that 11 and 12, but not 8, underwent aggregation in aqueous solution at the concentrations tested.