Synthesis of β-Cyclodextrin Diazonium Salts and Electrochemical Immobilization onto Glassy Carbon and Gold Surfaces

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((I))-catalyzed azide alkyne coupling (CuAAC) of 6-monodeoxy-6-monoazido-β-cyclodextrin (N(3)-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(3)Fe(CN)(6) 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.

Highly Efficient Rubber-to-Stainless Steel Bonding by Nanometer-Thin Cross-linked Polymer Brushes

“…The materials were all used without further purification, the exception being GMA and DEAEMA, which were passed through an aluminum oxide column before polymerization to remove the inhibitor. Standard procedures were followed to prepare the supporting electrolyte tetrabutylammonium tetrafluoroborate (Bu 4 NBF 4 ) and 4-(2-hydroxyethyl)­benzene diazonium tetrafluoroborate (HEBD). , Stainless steel (ASTM316) plates were cut into test pieces of 2 × 10 × 10 mm 3 size (Jensen Metal A/S, Denmark) (Supporting Information, Figure S1, item 4). They were polished for 1 h using a diamond suspension (Struer, grain size of 9 μm) followed by 10 min sonication in Milli-Q water and in acetone.…”

Spontaneous Aryldiazonium Grafting for the Preparation of Functional Cyclodextrin-Modified Materials

“…This is consistent with progressive partitioning of the more soluble Fc + species into the aqueous phase after each anodic sweep. 11 The total integrated charge associated with the anodic peak of the second cycle (0.2-0.5 V) was used to provide an estimate of surface coverage, Γ, for βCD-Fc complexes. Using equation (2) for a 1-electron transfer (n = 1), a scan rate ν = 0.2 V s -1 and an experimentally determined electrode geometric area 34 A = 0.196 cm 2 :…”

“…Examples of this include grafting to cellulose via acid crosslinking, 9 production of gold surfaces modified via thiolene chemistry, 10 and electrochemical grafting of cyclodextrins onto conductive surfaces. 6,11 Covalent immobilization of cyclodextrins has several benefits over physisorption and polymeric layer deposition, including coating stability and potential to retain surface properties and morphology.…”

Colorimetric detection of melamine using β-cyclodextrin-functionalized silver nanoparticles

“…1633 cm À1 , which are attributed to the OH stretching vibrations. [34][35][36] The bands that appeared at 2923 and 942 cm À1 are due to the C-H stretching and skeletal vibrations of a 1-4 linkage, whereas the bands observed at 761, 705 and 580 cm À1 are assigned to the pyranose ring vibrations. 37 The relative intensities of characteristic C-H, skeletal and pyranose ring stretching vibrations were decreased for the b-CD-functionalized Ag nanoparticles.…”