Realization of a Phenyl-Terminated Organic Surface and Its Interaction with Chromium Atoms

A phenyl-terminated organic surface was fabricated by self-assembly of phenyltricosanethiolate monolayers (C<INF>6</INF>H<INF>5</INF>(CH<INF>2</INF>)<INF>23</INF>SH) on polycrystalline gold substrates. The molecular orientation of the alkyl chain and the phenyl ring was determined by near edge X-ray absorption fine structure spectroscopy (NEXAFS). After chromium deposition a new resonance appeared in the NEXAFS spectra, which could be related to the formation of metal−π sandwich complexes by comparison to reference data recorded for multilayers of bis(benzene)chromium. This conclusion is supported by data recorded using X-ray photoelectron spectroscopy. Experiments carried out with a phenyl-terminated surface fabricated by using a short chain phenylalkanethiol demonstrate that a minimum chain length is required in order to avoid reactions of the deposited metal atoms with the gold substrate and/or with the C−S bonds.