Controlled Orientation of Cyclodextrin Derivatives Immobilized on Gold Surfaces

Several different cyclodextrinthiol derivatives have been
immobilized on gold surfaces through a
chemisorption process to form films which exhibit significantly
different features. Three monothiolated cyclodextrin
derivatives with different spacers between the cyclodextrin cavity and
the thiol group and a mixture of multithiolated
cyclodextrins were synthesized and characterized. Chemisorption of
these compounds onto gold surfaces gave films
which were investigated by Fourier transform infrared (FTIR)
spectroscopy, time-of-flight mass spectrometry, contact
angle measurements, plasmon surface polariton (PSP) spectroscopy, and
cyclic voltammetry. It was found that the
chemical structure of each cyclodextrin derivative had a strong
influence on the molecular architecture in the resulting
films, and in particular on the orientation of the cyclodextrin torus.
Models were developed to describe the molecular
arrangement in the films.