Large-scale honeycomb microstructures constructed by platinum-acetylide gelators through supramolecular self-assembly

A series of new platinum-acetylide complexes 4 a-4 c and 6 a-6 c were synthesized and characterized. The gelation properties of these compounds were investigated by the "stable-to-inversion-of-test-tube" method. Unlike compounds 4 a-4 c, amides 6 b and 6 c can gelate a variety of nonpolar alkyl solvents; this result indicates that the hydrogen bonds between amide groups play an important role in the formation of metallic organogels. Interestingly, compared to the typical morphologies of known organogels or metallic organogels, compounds 6 b and 6 c exhibited highly ordered honeycomb patterns on a large-scale (determined by SEM analysis). To investigate the driving forces for the self-assembly process, concentration-dependent ¹H NMR spectroscopy and a competitive experiment between hydrogen bonds were used to confirm that intermolecular hydrogen bonding play an essential role during the formation of supramolecular aggregates.