Synthesis, Electronic Properties, and Self-Assembly on Au{111} of Thiolated Phenylethynyl Phenothiazines

Thiolated phenylethynyl phenothiazines can be regarded as redox-active “alligator clips”. They are readily synthesized from ethynyl phenothiazines and show intense blue-green luminescence upon ultraviolet (UV) excitation. Cyclic voltammetry reveals reversible oxidation, also after the chemisorption of in situ liberated thiols on gold electrodes. The chemisorption on Au{111} was studied by ellipsometry, contact angle measurements, X-ray photoelectron spectroscopy, and infrared reflection absorption spectroscopy, and the obtained data support the formation of self-assembled monolayers, depending on the structure of the substrates. These findings classify them as promising candidates for molecular wires switchable by redox manipulation.