Phenylboronic ester- and phenylboronic acid-terminated alkanethiols on gold surfaces
2012 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, no 1, 796-806 p.Article in journal (Refereed) Published
In this work, it is shown that a well-organized monolayer of phenylboronic ester-terminated thiol (BOR-capped) on gold surfaces can be prepared. Our results also show that the BOR-capped molecular system can be cleaved directly on the surface, resulting in an unprotected BOR-uncapped monolayer with the boronic acid functional groups available for coordination to diol molecules in the ambient media. The monolayers of BOR-capped and BOR-uncapped were characterized using infrared spectroscopy, near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, ellipsometry, and contact angle goniometry. The X-ray photoelectron spectroscopy results showed that both BOR-capped and BOR-uncapped are chemically linked to the gold substrate. According to the infrared spectroscopy results, the main component of the C=O vibrational mode present in the amide moiety is perpendicular oriented relative to the gold surface normal for the BOR-capped molecular system. The near edge X-ray absorption fine structure spectroscopy resonance peak located at approximately 285 eV, assigned to π 1* transitions, was used to estimate the average tilt angle of the vector parallel to the π* orbitals of the aromatic ring relative to the gold surface normal. The average tilt angle is estimated to be approximately 63° for the BOR-capped monolayer on gold surfaces. The aromatic ring of the BOR-uncapped molecule has a more tilted orientation compared to the BOR-capped one. The experimental infrared spectroscopy and near edge X-ray absorption fine structure spectroscopy results were supported with theoretical modeling including calculations of vibrational modes and of excitation processes.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2012. Vol. 116, no 1, 796-806 p.
Alkanethiols, Ambient media, Amide moieties, Aromatic rings, Boronic acid, Contact angle goniometry, Excitation process, Gold substrates, Gold surfaces, Main component, Molecular systems, Near edge x-ray absorption fine structure spectroscopies, Orbitals, Resonance peak, Theoretical modeling, Tilt angle, Vibrational modes, Amides, Aromatic compounds, Contact angle, Esterification, Esters, Functional groups, Gold, Infrared spectroscopy, Monolayers, Organic acids, Photons, X ray absorption, X ray absorption fine structure spectroscopy, X ray photoelectron spectroscopy
IdentifiersURN: urn:nbn:se:kth:diva-198746DOI: 10.1021/jp208597xISI: 000298978700098ScopusID: 2-s2.0-84855901073OAI: oai:DiVA.org:kth-198746DiVA: diva2:1059074
QC 201612222016-12-222016-12-212016-12-22Bibliographically approved