title: Grafting of functionalized [Fe(III)(salten)] complexes to Au(111) surfaces via thiolate groups: surface spectroscopic characterization and comparison of different linker designs.
abstract: Functionalization of surfaces with spin crossover complexes is an intensively studied topic. Starting from dinuclear iron(III)-salten complexes [Fe(salten)(pyS)]2(BPh4)2 and [Fe(thiotolylsalten)(NCS)]2 with disulfide-containing bridging ligands, corresponding mononuclear complexes [Fe(salten)(pyS)](+) and [Fe(thiotolylsalten)(NCS)] are covalently attached to Au(111) surfaces (pySH, pyridinethiol; salten, bis(3-salicylidene-aminopropyl)amine). The adsorbed monolayers are investigated by infrared reflection absorption spectroscopy (IRRAS) in combination with X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS). Comparison of the surface vibrational spectra with bulk data allows us to draw conclusions with respect to the geometry of the adsorbed complexes. An anomaly is observed in the spectra of the surface-adsorbed monolayer of [Fe(salten)(pyS)](+), which suggests that the salten ligand is partially decoordinated from the Fe(III) center and one of its phenolate arms binds to the Au(111) surface. For complex [Fe(thiotolylsalten)(NCS)] that is bound to the Au(111) surface via a thiolate-functionalized salten ligand, this anomaly is not observed, which indicates that the coordination sphere of the complex in the bulk is retained on the surface. The implications of these results with respect to the preparation of surface-adsorbed monolayers of functional transition-metal complexes are discussed.
authors.affiliation: Institut für Anorganische Chemie, Christian-Albrechts-Universität Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany.
authors.forename: Hanne
authors.initials: H
authors.lastname: Jacob
authors.forename: Ketheeswari
authors.initials: K
authors.lastname: Kathirvel
authors.forename: Finn
authors.initials: F
authors.lastname: Petersen
authors.forename: Thomas
authors.initials: T
authors.lastname: Strunskus
authors.forename: Alexander
authors.initials: A
authors.lastname: Bannwarth
authors.forename: Sven
authors.initials: S
authors.lastname: Meyer
authors.forename: Felix
authors.initials: F
authors.lastname: Tuczek
mesh_terms: D005029:Ethylenediamines / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D056928:X-Ray Absorption Spectroscopy; D014965:X-Rays
chemical_list: D005029:Ethylenediamines; D005290:Ferric Compounds; D013438:Sulfhydryl Compounds; D006046:Gold; C011452:disalicylaldehyde ethylenediamine