Surface-enhanced resonance Raman spectroscopy of tris(2,2'-bipyridine) ruthenium(II) and substituted analogues on novel-vapour-deposited surfaces

The preparation of a new, reproducible vapour silver-coated polycarbonate SER(R)S-active substrate is reported. The SERRS of the optimised surface with the complex tris(2,2'-bipyridine) ruthenium(II) ([Ru(bipy)(3)](2+)) and ligand-modified analogues, comprising tris(4,4'-diamino and -diphenyl-2,2'-bipyridine) and tris(diethyl-2,2'-bipyridine-4,4'-dicarboxylate) ruthenium(II), is reported and compared with the spectra of identical concentrations of each complex on chemically-deposited silver slides. Whereas the silver slide spectra show very strong physisorptive (purely electromagnetic) SERRs enhancement, the polycarbonate spectra exhibit lower degrees of enhancement but with a small associated chemisorptive (charge-transfer) effect. The adsorptive process on the silver polycarbonate surface is discussed.