scholarly journals Effective Enantiodiscrimination in Electroanalysis Based on a New Inherently Chiral 1,1′-Binaphthyl Selector Directly Synthesizable in Enantiopure Form

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2175
Author(s):  
Giorgia Bonetti ◽  
Serena Arnaboldi ◽  
Sara Grecchi ◽  
Giulio Appoloni ◽  
Elisabetta Massolo ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrode Surface ◽  
Potential Difference ◽  
Synthetic Route ◽  
Hplc Separation ◽  
Chiral Selectors ◽  
Electrode Surfaces ◽  
Inherently Chiral

Enantioselective electroanalysis, which aims to discriminate the enantiomers of electroactive chiral probes in terms of potential difference, is a very attractive goal. To achieve this, its implementation is being studied for various "inherently chiral" selectors, either at the electrode surface or in the medium, yielding outstanding performance. In this context, the new inherently chiral monomer Naph2T4 is introduced, based on a biaromatic atropisomeric core, which is advantageously obtainable in enantiopure form without HPLC separation steps by a synthetic route hinging on enantiopure 2,2’-dibromo-1,1’-binaphthalenes. The antipodes of the new inherently chiral monomer can be easily electrooligomerized, yielding inherently chiral electrode surfaces that perform well in both cyclic voltammetry (CV) enantiodiscrimination tests with pharmaceutically interesting molecules and in magnetoelectrochemistry experiments.

scholarly journals Voltammetry and molecular assembly of G-quadruplex DNAzyme on single-crystal Au(111)-electrode surfaces – hemin as an electrochemical intercalator

2016 ◽  
Vol 193 ◽  
pp. 99-112 ◽  
Author(s):  
Ling Zhang ◽  
Jens Ulstrup ◽  
Jingdong Zhang
Keyword(s):  
Single Crystal ◽  
Single Molecule ◽  
Electrode Surface ◽  
Molecular Assembly ◽  
Electrode Surfaces ◽  
Potential Control ◽  
G Quadruplex ◽  
Tunnelling Microscopy ◽  
Dna Quadruplexes

DNA quadruplexes (qs) are a class of “non-canonical” oligonucleotides (OGNs) composed of stacked guanine (G) quartets stabilized by specific cations. Metal porphyrins selectively bind to G-qs complexes to form what is known as DNAzyme, which can exhibit peroxidase and other catalytic activity similar to heme group metalloenzymes. In the present study we investigate the electrochemical properties and the structure of DNAzyme monolayers on single-crystal Au(111)-electrode surfaces using cyclic voltammetry and scanning tunnelling microscopy under electrochemical potential control (in situ STM). The target DNAzyme is formed from a single-strand OGN with 12 guanines and iron(iii) porphyrin IX (hemin), and assembles on Au(111) through a mercapto alkyl linker. The DNAzyme monolayers exhibit a strong pair of redox peaks at 0.0 V (NHE) at pH 7 in acetate buffer, shifted positively by about 50 mV compared to free hemin weakly physisorbed on the Au(111)-electrode surface. The voltammetric hemin signal of DNAzyme is enhanced 15 times compared with that of hemin adsorbed directly on the Au(111)-electrode surface. This is indicative of both the formation of a close to dense DNAzyme monolayer and that hemin is strongly bound to the immobilized 12G-qs in well-defined orientation favorable for interfacial ET with a rate constant of 6.0 ± 0.4 s−1. This is supported by in situ STM which discloses single-molecule G-quartet structures with a size of 1.6 ± 0.2 nm.

Synthesis and antiaromatic character of alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex

2017 ◽  
Vol 21 (12) ◽  
pp. 850-856 ◽  
Author(s):  
Masataka Umetani ◽  
Koji Naoda ◽  
Takayuki Tanaka ◽  
Atsuhiro Osuka
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Potential Difference ◽  
Planar Structure ◽  
H Nmr ◽  
Antiaromatic Character ◽  
Homo Lumo ◽  
Nmr Signals

Antiaromatic molecules have recently been proven to display unique properties such as small HOMO–LUMO gaps, ambipolar carrier transporting and [Formula: see text]-stack-induced aromatic stabilizations. These intriguing properties have been demonstrated by stable antiaromatic molecules that exhibit a distinct antiaromatic character. Di-peri-dinaphthoporphyrins are peripherally [Formula: see text]-extended porphyrinoids that exhibit a planar structure and a distinct antiaromatic character stemming from their 24[Formula: see text] electron circuit. Herein, we report an alkyl-substituted di-peri-dinaphthoporphyrin Ni(II) complex 5Ni bearing less peripheral bulkiness as compared with phenyl-substituted ones. 5Ni displayed upfield-shifted [Formula: see text]H NMR signals due to [Formula: see text]-protons, indicating its distinct antiaromaticity, and a slightly shorter intermolecular packing distance (ca. 3.402 Å) in the solid state. Cyclic voltammetry shows a larger potential difference between the first and second oxidation waves, implying that this molecule tends to stack favorably in its oxidized state.

Macrocyclic glycopeptide chiral selectors bonded to core-shell particles enables enantiopurity analysis of the entire verubecestat synthetic route

2018 ◽  
Vol 1539 ◽  
pp. 87-92 ◽  
Author(s):  
Chandan L. Barhate ◽  
Diego A. Lopez ◽  
Alexey A. Makarov ◽  
Xiaodong Bu ◽  
William J. Morris ◽  
...  
Keyword(s):  
Core Shell ◽  
Synthetic Route ◽  
Chiral Selectors ◽  
Macrocyclic Glycopeptide ◽  
Shell Particles

scholarly journals Investigation of Electrochemical Behaviour of Quercetin on the Modified Electrode Surfaces with Procaine and Aminophenyl in Non-Aquous Medium

2008 ◽  
Vol 5 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Ibrahim Ender Mulazimoglu ◽  
Erdal Ozkan
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Glassy Carbon ◽  
Electrode Surface ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Carbon Electrode ◽  
Amine Group ◽  
Tetrabutylammonium Tetrafluoroborate

In this study, cyclic voltammetry and electrochemical ımpedance spectroscopy have been used to investigate the electrochemical behaviour of quercetin (3,3′,4′,5,7-pentahydroxyflavone) on the procaine and aminophenyl modified electrode. The modification of procaine and aminophenyl binded electrode surface with quercetin was performed in +0,3/+2,8 V (for procaine) and +0,4/+1,5 V (for aminophenyl) potential range using 100 mV s-1scanning rate having 10 cycle. A solution of 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile was used as a non-aquous solvent. For the modification process a solution of 1 mM quercetin in 0.1 M tetrabutylammonium tetrafluoroborate was used. In order to obtain these two surface, a solution of 1 mM procaine and 1 mM nitrophenyl diazonium salt in 0.1 M tetrabutylammonium tetrafluoroborate was used. By using these solutions bare glassy carbon electrode surface was modified. Nitrophenyl was reduced to amine group in 0.1 M HCl medium on the nitrophenyl modified glassy carbon elelctrode surface. Procaine modified glassy carbon electrode surface was quite electroactive. Although nitrophenyl modified glassy carbon elelctrode surface was electroinactive, it was activated by reducing nitro group into amine group. For the characterization of the modified surface 1 mM ferrocene in 0.1 M tetrabutylammonium tetrafluoroborate for cyclic voltammetry and 1 mM ferricyanide/ferrocyanide (1:1) mixture in 0,1 M KCl for electrochemical impedance spectroscopy were used.

scholarly journals Use of ‘solid-state’ promoters in the electrochemistry of cytochrome c at a gold electrode

1991 ◽  
Vol 273 (3) ◽  
pp. 783-786 ◽  
Author(s):  
R Santucci ◽  
A Faraoni ◽  
L Campanella ◽  
G Tranchida ◽  
M Brunori
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Cytochrome C ◽  
Gold Electrode ◽  
Direct Electrochemistry ◽  
Protoporphyrin Ix ◽  
Cellulose Triacetate ◽  
Electrode Surfaces ◽  
Inert Electrode ◽  
Hydrolysis Of

The direct electrochemistry of cytochrome c at a gold electrode was investigated by cyclic voltammetry using, as promoters, microperoxidase (the haem-undecapeptide obtained by hydrolysis of cytochrome c), Fe(III)-protoporphyrin IX or protoporphyrin-IX, all entrapped in a cellulose triacetate membrane. The results indicate that these immobilized systems strongly enhance the rate of electron transfer between the protein in solution and the electrode surface, and thus behave as ‘solid-state’ promoters, though with differing efficiencies. These results are of interest because they raise the possibility of engineering an efficient and versatile promoter active also at inert electrode surfaces.

scholarly journals Electrochemical Synthesis of Polyaniline/Poly-O-Aminophenol Copolymers in Chloride Medium

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Lucia H. Mascaro ◽  
Alessandra N. Berton ◽  
Liliana Micaroni
Keyword(s):  
Cyclic Voltammetry ◽  
Conducting Polymer ◽  
Electrochemical Synthesis ◽  
Electrode Surface ◽  
Oxidation Products ◽  
Monomer Mixture ◽  
Nacl Solution ◽  
Chloride Medium ◽  
Vis Spectroscopy

The copolymerization ofo-aminophenol (OAP) and aniline (ANI) on Pt and ITO electrodes was studied using cyclic voltammetry in 0.1 M HCl/0.4 M NaCl solution. The films were characterized by SEM, cyclic voltammetry, and UV-Vis spectroscopy. The properties of the copolymer were compared with PANI and POAP films. The results strongly suggest that the growth of PANI-POAP films does not consist of the simple buildup of layers of homopolymers on the electrode surface as a result of OAP or ANI oxidation products in the monomer mixture, but that a new conducting polymer is formed by copolymerization.

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