Raman Spectroscopy of Biphenyl‐4,4'‐dithiol and p ‐Terphenyl‐4,4″‐dithiol on Gold Surfaces #

We compared the adsorption behaviors of 1,4‐benzenedithiol ( BDT ), biphenyl‐4,4′‐dithiol ( BPDT ), and p ‐terphenyl‐4,4″‐dithiol ( TPDT ) on gold (Au) surfaces. To check the surface orientations and possibility of multilayer formation, surface‐enhanced Raman scattering was employed for the three aromatic dithiols on gold nanoparticles ( AuNPs ). The Raman spectra of BDT and BPDT on AuNPs were examined, whereas those of TPDT could be obtained on an Au‐coated nanostructured silicon plate. Unlike BDT , BPDT and TPDT did not exhibit a ν( S–H ) band at 2560 cm −1 . Because of the additional benzene rings, multilayer formation is improbable for BPDT and TPDT under colloidal conditions.