Self-assembled monolayers of disulfide-functionalized diacetylenes on gold films and nanoparticles

This paper reports on the fabrication of self-assembled monolayers containing disulfide-functionalized diacetylenes. To this purpose, two diacetylene derivatives were synthesized: the novel 14-(9H-9-carbazolyl)tetradeca-10,12-diyn-1-yl disulfide (CDS9) and the henicosa-10,12-diyn-1-yl disulfide (DS9). Both monomers were employed to prepare two-dimensional self-assembled monolayers (2D-SAMs) by chemisorption on gold-sputtered platforms and three-dimensional self-assembled monolayers (3D-SAMs) on gold nanoclusters by direct synthesis in organic solvent. The chemisorbed diacetylenes were then converted to the polymeric form by exposure to UV radiation, and their morphological and spectroscopic properties investigated by several techniques. From SERS data it was inferred that both monomers show the same behavior, in that the highly conjugated blue phase was observed in the 3D-SAMs, while only the less extended red conformation was found in the corresponding 2D-SAMs.