title: Investigation of the SERS behaviour of porphyrins with different surface concentrations on electrochemically prepared Ag-surface.
abstract: Surface-enhanced Raman scattering (SERS) spectra, taken with 632.8 nm excitation are reported for the water-soluble tetrakis(3-N-methylpyridyl)porphyrin chloride (TMPyP(3)), tetrakis(4-N-methylpyridyl)porphyrin chloride (TMPyP(4)) and Sn(IV)tetrakis(4-N-methylpyridyl)porphyrin chloride (Sn(IV)TMPyP(4)) using an electrochemically prepared Ag surface with an area ca. 12.56 mm2. It was found that the spectra vary as increasing amounts of the compounds are placed on the surface, with surface concentrations in the approximate range 1000-5 pmol/12.56 mm2. We suggest that the reasons for the changes be that the reaction means between porphyrin molecules and Ag surface is different and the porphyrin macrocyclic molecules adopt different orientation as the surface concentrations decrease.
authors.affiliation: Department of Chemical Engineering, Hubei Institute of Technology, Wuhan, PR China. qujinrong@363.net
authors.forename: J
authors.initials: J
authors.lastname: Qu
authors.forename: P M
authors.initials: PM
authors.lastname: Fredericks
mesh_terms: D004563:Electrochemistry; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry* / Q000302:isolation & purification; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods
chemical_list: D011166:Porphyrins; D012834:Silver