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 (C6H5(CH2)(23)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-pi 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.