Surface Science of Soft Scorpionates

The chemisorption of the soft scorpionate Li[PhTm<sup>Me</sup>] onto silver and gold surfaces is reported. Surface enhanced Raman spectroscopy in combination with the Raman analysis of suitable structural models, namely, [Cu(κ<sup>3</sup>-S,S,S-PhTm<sup>Me</sup>)(PCy<sub>3</sub>)], [Ag(κ<sup>3</sup>-S,S,S-PhTm<sup>Me</sup>)(PCy<sub>3</sub>)], [Ag(κ<sup>2</sup>-S,S-PhTm<sup>Me</sup>)(PEt<sub>3</sub>)], and [Au(κ<sup>1</sup>-S-PhTm<sup>Me</sup>)(PCy<sub>3</sub>)], 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<sup>Me</sup> 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.