Synthesis of β‑Cyclodextrin
Diazonium
Salts and Electrochemical Immobilization onto Glassy Carbon and Gold
Surfaces
- Publication date
- Publisher
Abstract
This study shows that diazotized β-cyclodextrin
(β-CD)
can be produced, isolated, and immobilized onto glassy carbon and
gold surfaces. 4-(1,2,3-Triazol-4-yl)benzenediazonium-β-CD tetrafluoroborate
(pDz-β-CD) and 3-(1,2,3-triazol-4-yl)benzenediazonium-β-CD
tetrafluoroborate (mDz-β-CD) were successfully prepared by Cu<sup>(I)</sup>-catalyzed azide alkyne coupling (CuAAC) of 6-monodeoxy-6-monoazido-β-cyclodextrin
(N<sub>3</sub>-β-CD) and 4-ethynylaniline and 3-ethynylaniline,
respectively, followed by diazotization. The products were isolated
and stored successfully for several months at −18 °C.
The intermediates and products were verified by Attenuated Total Reflectance
Fourier Transform Infrared, Nuclear Magnetic Resonance, and Heteronuclear
Single Quantum Coherence.pDz-β-CD and mDz-β-CD
were immobilized onto glassy
carbon and gold surfaces facilitated by electrochemical reduction
of the diazonium group. The thus generated aryl radical reacted with
the surface. The modified gold surfaces were investigated by Polarization
Modulation Infrared Reflection Absorption Spectroscopy and cyclic
voltammetry employing the redox probe K<sub>3</sub>Fe(CN)<sub>6</sub> to analyze the extent of blocking of the surfaces. Finally, the
availability of the cavity of surface-immobilized β-CD was shown
by complexation of ferrocene followed by cyclic voltametric analysis