Surface Science of Soft Scorpionates

The chemisorption of the soft scorpionate Li[PhTm^Me] onto silver and gold surfaces is reported. Surface enhanced Raman spectroscopy in combination with the Raman analysis of suitable structural models, namely, [Cu(κ³-S,S,S-PhTm^Me)(PCy₃)], [Ag(κ³-S,S,S-PhTm^Me)(PCy₃)], [Ag(κ²-S,S-PhTm^Me)(PEt₃)], and [Au(κ¹-S-PhTm^Me)(PCy₃)], are employed to identify the manner in which this potentially tridentate ligand binds to these surfaces. On colloidal silver surface-enhanced Raman spectroscopy (SERS) spectra are consistent with PhTm^Me binding in a didentate fashion to the surface, holding the aryl group in close proximity to the surface. In contrast, on gold colloid, we observe that the species prefers a monodentate coordination in which the aryl group is not in close proximity to the surface.