Selective activation of glycosyl donors utilising electrochemical techniques: a study of the thermodynamic oxidation potentials of a range of chalcoglycosides

2004 ◽  
Vol 2 (15) ◽  
pp. 2188 ◽  
Author(s):  
Robert R. France ◽  
Neil V. Rees ◽  
Jay D. Wadhawan ◽  
Antony J. Fairbanks ◽  
Richard G. Compton
Keyword(s):  
Electrochemical Techniques ◽  
Selective Activation ◽  
Oxidation Potentials ◽  
Glycosyl Donors

scholarly journals Disposable Voltammetric Sensor Modified with Block Copolymer-Dispersed Graphene for Simultaneous Determination of Dopamine and Ascorbic Acid in Ex Vivo Mouse Brain Tissue

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 368
Author(s):  
Dinakaran Thirumalai ◽  
Seulah Lee ◽  
Minho Kwon ◽  
Hyun-jong Paik ◽  
Jaewon Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ascorbic Acid ◽  
Block Copolymer ◽  
Electrochemical Impedance ◽  
Ex Vivo ◽  
Electrochemical Techniques ◽  
Linear Sweep Voltammetry ◽  
Voltammetric Sensor ◽  
Peak Separation ◽  
Oxidation Potentials

Dopamine (DA) and ascorbic acid (AA) are two important biomarkers with similar oxidation potentials. To facilitate their simultaneous electrochemical detection, a new voltammetric sensor was developed by modifying a screen-printed carbon electrode (SPCE) with a newly synthesized block copolymer (poly(DMAEMA-b-styrene), PDbS) as a dispersant for reduced graphene oxide (rGO). The prepared PDbS–rGO and the modified SPCE were characterized using a range of physical and electrochemical techniques including Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry. Compared to the bare SPCE, the PDbS–rGO-modified SPCE (PDbS–rGO/SPCE) showed better sensitivity and peak-to-peak separation for DA and AA in mixed solutions. Under the optimum conditions, the dynamic linear ranges for DA and AA were 0.1–300 and 10–1100 µM, and the detection limits were 0.134 and 0.88 µM (S/N = 3), respectively. Furthermore, PDbS–rGO/SPCE exhibited considerably enhanced anti-interference capability, high reproducibility, and storage stability for four weeks. The practical potential of the PDbS–rGO/SPCE sensor for measuring DA and AA was demonstrated using ex vivo brain tissues from a Parkinson’s disease mouse model and the control.

The Selective Activation of Telluro- over Seleno-β-D-glucopyranosides as Glycosyl Donors: a Reactivity Scale for Various Telluro, Seleno and Thio Sugars

1997 ◽  
Vol 50 (3) ◽  
pp. 237 ◽  
Author(s):  
Robert V. Stick ◽  
D. Matthew G. Tilbrook ◽  
Spencer J. Williams
Keyword(s):  
Trifluoromethanesulfonic Acid ◽  
Selective Activation ◽  
The One ◽  
Glycosyl Donors

Phenyl tetra-O-benzoyl-1-telluro-β-D-glucopyranoside, when treated with 1,2:3,4-di-O-isopropylidene-α-D-galactose in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid, immediately forms the expected β-disaccharide derivative. A subsequent experiment involving both a telluroglycoside and a selenoglycoside as donors with the one alcohol acceptor showed complete preference for the telluroglycoside. This result has led to an extension of the investigation to establish a ‘reactivity scale’ for various telluro, seleno and thio sugars.

Synthesis, characterization, redox, and Hg2+ optical ion sensing properties of ferrocenyl-containing maleo- and fumaronitrile derivatives

2014 ◽  
Vol 92 (8) ◽  
pp. 739-749 ◽  
Author(s):  
Michael R. Dahlby ◽  
Anatolii A. Purchel ◽  
Pavlo V. Solntsev ◽  
Gregory T. Rohde ◽  
Yuriy V. Zatsikha ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Charge Transfer Band ◽  
Electrochemical Techniques ◽  
Mixed Valence ◽  
Reaction Products ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Oxidation Potentials

Mono-((Z)-2-amino-3-((E)-ferrocenylideneamino)butenedinitrile) (1) and bis-((E)-2,3-bis-((E)-ferrocenylideneamino)butenedinitrile) (2) substituted Schiff bases obtained by the reaction between ferrocenecarbaldehyde and diaminomaleonitrile were prepared and characterized by 1H and 13C NMR, IR, and UV-vis-NIR spectroscopy methods, elemental analysis, and X-ray crystallography. Density functional theory and time-dependent density functional theory were used to elucidate the electronic structure and the origin of observed excited states in both compounds. Electrochemical techniques were employed to investigate the possibility for the formation of a mixed-valence state of the iron centers in 2+, which are connected by a conjugated π-system. Two reversible oxidation potentials were observed in cyclic voltammetry, and spectroelectrochemical experiments revealed the presence of a low-energy intervalence charge transfer band in 2+, corresponding to class II of the mixed-valence systems. Both complexes were tested for cation-recognition properties using a variety of main group and transition-metal cations. It was shown that complex 1 can be used as a selective optical sensor in recognition of Hg2+ ions. It was also shown by NMR spectroscopy and X-ray crystallography that one of the final reaction products between Hg2+ ions and complex 1 is 2-ferrocenyl-4,5-dicyanoimidazole (3).

Ubiquinone-BODIPY nanoparticles for tumor redox-responsive fluorescence imaging and photodynamic activity

2021 ◽  
Author(s):  
Byunghee Hwang ◽  
Tae-Il Kim ◽  
Hyunjin Kim ◽  
Sungjin Jeon ◽  
Yongdoo Choi ◽  
...  
Keyword(s):  
Fluorescence Imaging ◽  
Selective Activation ◽  
Turn On ◽  
Intracellular Environment ◽  
Redox Responsive ◽  
Photodynamic Activity

A ubiquinone-BODIPY photosensitizer self-assembles into nanoparticles (PS-Q-NPs) and undergoes selective activation within the highly reductive intracellular environment of tumors, resulting in “turn-on” fluorescence and photosensitizing activities.

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