Abstract
Sum frequency generation (SFG) vibrational spectroscopy analyses were performed on self-assembled monolayers (SAMs) formed via the adsorption of 2-(4-(octadecyloxy)phenylethanethiol (R1ArMT), 2-(3,5-bis(octadecyloxy)phenylethanethiol (R2ArMT), and 2-(3,4,5-tris(octadecyloxy)phenyl-ethanethiol (R3ArMT) on gold. SFG spectra showed that the monolayers formed were closely packed and well ordered. It was determined, using orientation analysis, that as additional octadecyloxy chains were attached to the aromatic ring the apparent methyl group tilt increased and conformational order decreased. Aromatic C–H modes exhibited in the SFG spectra suggest the aromatic rings have a C2 axis along the surface normal. Model phenylethanethiols with different symmetries along the benzene ring were synthesized and used to identify vibrational modes and the surface orientation of the alkoxyphenylethanethiols. SAMs derived from R1ArMT exhibit aromatic C–H stretching modes due to the C2v symmetry at the ring. In contrast, SAMs derived from R2ArMT and R3ArMT exhibit no aromatic C–H stretching modes due to their low Raman cross section.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
