• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.629-632
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• 1991

The rate constants for the formation and dissociation of nickel(II) and cobalt(II) complexes with mandelate have been determined by the pressure-jump relaxation study. The forward and reverse rate constants for the mandelate complex formation reactions were obtained to be $k_f=3.60{\times}10^4\;M^{-1}s^{-1}$ and $k_r=1.73{\times}10^2\;s^{-1}$ for the nickel(II), and $k_f=1.75{\times}10^5\;M^{-1}s{-1}$ and $2.33{\times}10^3\;s^{-1}$ for the cobalt(II) in aqueous solution of zero ionic strength ($(\mu{\to}0)\;at\;25^{\circ}C$. The results were interpreted by the use of the multistep complex formation mechanism. The rate constants evaluated for each individual steps in the multistep mechanism draw a conclusion that the rate of the reaction would be controlled by the chelate ring closure step in concert with the solvent exchange step in the nickel(II) complexation, while solely by the chelate ring closure step for the cobalt(II) complex.

• Journal of the Korean Chemical Society
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• v.42 no.3
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• pp.340-344
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• 1998

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1122-1124
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• 1994

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1382-1385
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• 1998

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.358-360
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• 1990

• Rapid Communication in Photoscience
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• v.5 no.2
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• pp.16-17
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• 2016

Arylalkyne cobalt complexes 5, 6 were prepared and irradiated with e-beam to study their fragmentation focused in alkyne formation. Thioaryl complex 6 showed facile CO ligand release and generated parent alkyne in 89% relative intensity. Meanwhile, hydroxyaryl complex 5 gave alkyne in 6% relative intensity.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.177-183
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• 1998

By the reactions of a $C_{2}$-chiral ligand, (+)-11S,12S-bis[2,2'-(diphenylphosphino)benzanilido]-9,10-dihydro-9,10-ethanoanthracene(6) with $[\pi-allyl chloroplatinum(II)]_4$, and $CpCo(CO)_2$ respectively, three new complexes, ($\pi$-allyl)platinum(II)(+)-11S,12S-bis[2,2'-(diphenylphosphino)benzanilido]-9,10-dihydro-9,10-ethanoanthracene perchlorate(1), ($\pi$-allyl)platinum(II)(+)-11S,12S-bis[2,2'-(diphenylphosphino)benzanilido]-9,10-dihydro-9,10-ethanoanthracene chloride(2), ($\eta^5$-cyclopentadienyl)cobalt(I)-(+)-11S,12S-bis[2,2'-(diphenylphosphino)benzanilido]-9,10-dihydro-9,10-ethanoanthracene(3) were prepared. $\eta^3$-Cyclohexenyl)palladium(II)1,2-bis(diphenylphosphino)ethane perchlorate(4) was obtained by the reaction of ($\eta^3$-cyclohexenyl)palladium(II) chloride dimer with a symmetric ligand, 1,2-bis(diphenylphosphino)ethane and lithium perchlorate. These complexes were identified by NMR-, IR-, and Mass-Spectrophotometers and elemental analyzer.

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

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4028-4034
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• 2012

Tris(2-phenylphenoxo)aluminum ($(2-PhC_6H_4O)_3Al$) exists as a dimeric form in toluene. When toluene-insoluble anhydrous cobalt acetate is treated with tris(2-phenylphenoxo)aluminum in toluene, the toluene-soluble adduct $(2-PhC_6H_4O)_3Al{\cdot}Co(OAc)_2$ is formed. The 2-phenylphenoxo ligand in the adduct can be replaced with another aryloxo ligand to give (aryloxo)$(2-PhC_6H_4O)_2Al{\cdot}Co(OAc)_2$ (aryloxo = 2-methylphenoxo, 2-isopropylphenoxo, 4-methylphenoxo, 4-isopropylphenoxo, or 4-tert-butylphenoxo). These complexes are active for butadiene polymerization without gel formation when activated with an equivalent amount of $(2-PhC_6H_4O)AlEt_2$ for 2 h. The highest activity, 175 kg/mol-Co (turnover number, 3200) was achieved with $(2-PhC_6H_4O)_3Al{\cdot}Co(OAc)_2$ at $65^{\circ}C$ for 2 h. The microstructure of the polymer chains is mostly trans-1,4-configuration (70-75%) with the remaining being 1,2-vinyl. The cis-1,4-configuration observed by IR is minimal (1-5%). By replacing the 2-phenylpheoxo with a 4-alkylphenoxo ligand, the amount of 1,4-configuration slightly increases, resulting in increase in the endothermic melting signal at $-30{\sim}50^{\circ}C$ in the DSC curve. The molecular weights of the polymers are high ($M_n$: 300000~800000) with a fairly narrow molecular weight distribution ($M_w/M_n$, 2.0-2.7).

• Current Photovoltaic Research
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• v.2 no.1
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• pp.18-27
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• 2014

Dye-sensitized solar cells (DSSCs), developed two decades ago, are considered to be an attractive technology among various photovoltaic devices because of their low cost, accessible dye chemistry, ease of fabrication, high power conversion efficiency, and environmentally friendly nature. A typical DSSCs consists of a dye-coated $TiO_2$ photoanode, a redox electrolyte, and a platinum (Pt)-coated fluorine-doped tin oxide (FTO) counter electrode. Among them, redox electrolytes have proven to be extremely important in improving the performance of DSSCs. Due to many drawbacks of iodide electrolytes, many research groups have paid more attention to seeking other alternative electrolyte systems. With regard to this, one-electron outer sphere redox shuttles based on cobalt complexes have shown promising results: In 2014, porphyrin dye (SM315) with the cobalt (II/III) redox couple exhibited a power conversion efficiency of 13% in DSSCs. In this review, we will provide an overview and perspectives of cobalt redox electrolytes in DSSCs.