• Bulletin of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.715-720
• /
• 2014

A Cu(II) complex with an three nitrogens and one sulfur coordination environment was synthesized and characterized. Its redox potential was observed at 0.483 V vs. NHE, very similar to that of a Cu-containing fungal enzyme, galactose oxidase, which catalyzes the oxidation of alcohols to corresponding aldehydes with the concomitant reduction of molecular oxygen to water. The Cu(II) complex selectively oxidizes the benzylic alcohols using TEMPO/$O_2$ under mild reaction conditions to corresponding aldehydes without forming any over-oxidation product. Moreover, the catalyst can be recovered and reused multiple times for further oxidation reactions, thus minimizing the waste generation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.11a
• /
• pp.365-366
• /
• 2008

• Journal of Electrochemical Science and Technology
• /
• v.9 no.3
• /
• pp.169-175
• /
• 2018

Cu-Salen complex was prepared and attached into chitosan (Cs) polymer backbone. Nanocomposite of the synthesized polymer was prepared with functionalized carbon nano-particles (Cs-Cu-sal/C) to modify the electrode surface. The surface morphology of (Cs-Cu-sal/C) nanocomposite film showed a homogeneous distribution of carbon nanoparticles within the polymeric matrix. The cyclic voltammogram of the modified electrode exhibited a redox behavior at -0.1 V vs. Ag/AgCl (3 M KCl) in 0.1 M PB (pH 7) and showed an excellent hydrogen peroxide reduction activity. The Cs-Cu-sal/C electrode displays a linear response from $5{\times}10^{-6}$ to $5{\times}10^{-4}M$, with a correlation coefficient of 0.993 and detection limit of $0.9{\mu}M$ (at S/N = 3). The sensitivity of the electrode was found to be $0.356{\mu}A\;{\mu}M^{-1}\;cm^{-2}$.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.811-812
• /
• 2010

• Journal of the Korean Electrochemical Society
• /
• v.13 no.1
• /
• pp.50-56
• /
• 2010

The multi-wall carbon nano-tube composite mixed with carbon paste electrode presented more sensitive and selective amperometric signals in the oxidation of glucose than general screen-printed carbon electrodes(SPCEs). Redox mediators to transport electrodes from enzyme to electrodes are very important part in the biosensor. A novel osmium redox complex was synthesized by the coordinating pyridine group containing primary amines which were electrochemically immobilized onto the MWCNT-SPCEs surface. Electrochemical studies of osmium complexes were investigated by cyclic voltammetry, chronoamperometry. The surface coverage of osmium complexes on the modified carbon nano-tube electrodes were significantly increased at 100 time (${\tau}_0=2.0\;{\times}\;10^{-9}\;mole/cm^2$) compared to that of the unmodified carbon electrodes. It's practical application of the glucose biosensor demonstrated that it shows good linear response to the glucose concentration in the range of 0-10 mM.

• Rapid Communication in Photoscience
• /
• v.2 no.2
• /
• pp.42-45
• /
• 2013

Natural photosynthesis utilizes solar energy to convert carbon dioxide and water to energy-rich carbohydrates. Substantial use of sunlight to meet world energy demands requires energy storage in useful fuels via chemical bonds because sunlight is intermittent. Artificial photosynthesis research focuses the fundamental natural process to design solar energy conversion systems. Nicotinamide adenine dinucleotide ($NAD^+$) and $NADP^+$ are ubiquitous as electron transporters in biological systems. Enzymatic, chemical, and electrochemical methods have been reported for NADH regeneration. As photochemical systems, visible light-driven catalytic activity of NADH regeneration was carried out using platinum nanoparticles, molecular rhodium and cobalt complexes in the presence of triethanolamine as a sacrificial electron donor. Pt nanoparticles showed photochemical NADH regeneration activity without additional visible light collector molecules, demonstrating that both photoactivating and catalytic activities exist together in Pt nanoparticles. The NADH regeneration of the Pt nanoparticle system was not interfered with the reduction of $O_2$. Molecular cobalt complexes containing dimethylglyoxime ligands also transfer their hydrides to $NAD^+$ with photoactivation of eosin Y in the presence of TEOA. In this photocatalytic reaction, the $NAD^+$ reduction process competed with a proton reduction.

• Applied Chemistry for Engineering
• /
• v.19 no.3
• /
• pp.277-286
• /
• 2008

This paper deals with the theoretical derivation of the modified Haldane model of the substrate inhibition in the microbial growth processes. Based on the biological concepts of substrate-receptor complex working mechanisms, a new microbial kinetics of N-fold multiplex substrate inhibition and its generalization has been considered theoretically, which is natural expansion of the simple substrate inhibition mechanism in the enzyme reaction. As a result, the modified Haldane model of the substrate inhibition turns out to be a well-designed four-parameter kinetic model with a biological constant of the total substrate inhibition concentration.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.1
• /
• pp.30-36
• /
• 2014

Redox complexes to transport electrons from enzyme to electrodes are very important part in glucose sensor. Pentacyanoferrate-bound aniline ($Fe(CN)_5$-aminopyridine), was prepared as a potential redox mediator in a glucose dehydrogenase (GDH)-glucose sensor. The synthesized pyridyl-$NH_2$ to pentacyanoferrate was characterized by the electrochemical and spectroscopic methods. A amperometric enzyme-linked electrode was developed based on GDH, which catalyses the oxidation of glucose. Glucose was detected using GDH that was co-immobilized with an $Fe(CN)_5$-aminopyridine and gold nano-particles (AuNPs) on ITO electrodes. The $Fe(CN)_5$-aminopyridine and AuNPs immobilized onto ITO electrodes provided about a two times higher electrochemical response compared to that of a bare ITO electrode. As glucose was catalyzed by wired GDH, the electrical signal was monitored at 0.4 V versus Ag/AgCl by cyclic voltammetry. The anode currents was linearly increased in proportion to the glucose concentration over the 0~10 mM range.