• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.436-442
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• 1994

Heterobimetallic complexes have a donor-accepter metal-metal bond in which two electrons from the electron-rich metal moiety are donated to the other electron-deficient one. Based on the competition reactions, Cotton-Kraihanzel force constants, ν(CO)IR band resolution and the relative nucleophilicity comparison of the donor ligands, the following relative ligating ability of the donor ligands toward $M(CO)_5$ (M=Cr, W) is assessed: cis-HW$(CO)_4P(OMe)_3^-$, $HW(CO)_5^-$ > $HCr(CO)_5^-$-$Br^-$ > trans-HFe$(CO)_3P(OMe)_3^-$ > $Mn(CO)_5^-$ > $HFe(CO)_4^-$ > PP$h_3$

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.176-183
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• 2020

In this study, synthesis of a hydrogel consisted of a coordination bond network between small organic molecules and transition metals had been carried out. By adding a tackifying material to the gel, the potential of the gel to be used as an adhesive material had been also confirmed. Synthesis of the adhesive had been done with simple mixing of 3 components: tannic acid, transition metal, and polymer. The tannic acid molecule possesses multiple hydroxyl groups that can form coordination bonds with the transition metals and hydrogen bonds with the hydrophilic polymers. Due to the morphology of the metal-organic complex and polymer dispersed in water, the fabricated material exhibited high adhesiveness and cohesiveness. Optimizing the rheological property had been conducted for use in adhesive by the synthesis with varying the transition metal (Fe³⁺, Ti⁴⁺), polymer, and treatment conditions. Rheological measurement results demonstrate the promising potential of the material as a bio-compatible and versatile pressure-sensitive adhesive with both high adhesiveness and cohesiveness.

• Bulletin of the Korean Chemical Society
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• v.10 no.5
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• pp.475-476
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• 1989

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.829-831
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• 2003

Various theoretical studies of σ-bond activation of organic molecules by transition metal complexes arereviewed. In the homolytic σ-bond activation, the d orbital energy level of the central metal is an importantfactor, as well known. At the same time, the electron-withdrawing substituent which stabilizes the sp3 orbitalaccelerates the homolytic σ-bond activation. In the heterolytic C-H σ-bond activation of RH by $MXL_n$, the XHbond formation is an important driving force, where $MRL_n$ and HX are formed as products. The heterolytic σ-bond activation is also understood in terms of the electrophilic attack of the metal center to the substrate.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.687-691
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• 1993

Complexation of $Cd^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions with four cryptands were studied by potentiometry and solution calorimetry in various weight percent methanol-aqueous solvent at 25${\circ}$C under $CO_2$free nitrogen atmosphere. The stabilities of the complexes were dependent on the cavity size of macrocycles. The $Hg^{2+}$ ion stability constants are higher than those of $Cd^{2+}\;and\;Pb^{2+}$ ion. All the cryptands formed complexes having 1 : 1 (metal to ligand) mole-ratio except for $Hg^{2+}-L_1$ (cryptand 1,2b: 3,5-benzo-9,14,17-trioxa-1,7-diazabicyclo-(8,5,5) heptadecane) and $Cd^{2+}-L_2$ (cryptand 2,2b: 3,5-benzo-10,13,18,21-tetraoxa-1,7-diazabicyclo (8,5,5) eicosane) complexes. $Hg^{2+}-L_1$ complex was a sandwitch type, and the $Cd^{2+}-L_2$ complex showed two stepwise reactions. Thermodynamic parameters of the $Cd^{2+}-L_2$ complex were $6.08(log\;K_1)$, -7.28 Kcal/mol $({\Delta}H_1)$, and $4.78\;(log\;K_2)$, -4.62 Kcal/mol $({\Delta}H_2)$, respectively, for 1 : 1 and 2: 1 mole-ratio. The sequences of the selectivity were increased in the order of $Hg^{2+}\;>Pb^{2+}\;>Cd^{2+}$ ion for $L_3\;and\;L_4$ macrocycles, and the $L_2$-macrocycle has a selectivity for $Cd^{2+}$ ion relative to $Zn^{2+},\;Ni^{2+},\;Pb^{2+}\;and\;Hg^{2+}$ ions. Thus, it is expected that the $L_2$ can be used as carrier for seperation of the post transition metals by macrocycles-mediated liquid membrane because $L_2$ is not soluble in water, and the difference of stability constants of the metal complexes with $L_2$ are large as compared with the other transition metal complexes. The $^1H\;and\;^{13}C-NMR studies indicated that the nitrogen atoms of cryptands have greater affinity to the post transition metal ions than the oxygen atoms, and that the planarities of the macrocycles were lost by complexation with the metal ions because of the perturbation of ring current of benzene molecule attached to macrocycles and counter-anions.

• Journal of the Korean Chemical Society
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• v.30 no.6
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• pp.526-531
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• 1986

The stability constants of 1,15-diaza-3,4:12,13-dibenzo-5,8,11-trioxacycloheptadecane (NenOdien H$_4$, L) with transition metal ions such as $Co^{2+},\;Ni^{2+},\;Cu^{2+},\;and\;Zn^{2+}$ have been determined by potentiometry in 95% methanol solution at 25$^{\circ}$C. The complex formation of the NenOdien $_4$ with the transition metal ions depends on the basicity of the donor atoms. The order of complex stability was Co(II) < Ni(II) < Cu(II) > Zn(II). The geometries of the complexes in solid state were discussed by visible-near infrared and infrared spectrophotometry, elemental analysis and electro-conductivity. The results suggest that the geometries of the solid complexes are octahedral for $[CoL_2(OH_2)Cl]Cl{\cdot}2H_2O$, $[NiL_2(OH_2)Cl]Cl{\cdot}2H_2O$, and $[ZnLCl_2]{\cdot}\frac{1}{2}H_2O$ and square pyramidal for [CuLCl]Cl, respectively.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.107-113
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• 2004

Several transition metal complexes, [$M(L)X_2$](M=Pd(II), Ni(II); X=CI, Br) are prepared with aminophosphine ligands such as 1,2-bis{(diphenylphosphino)amino}ethane{$Ph_2PNHCH_2CH_2NHPPh_2$}($L_1$), 1,2-bis{(diphenylphosphino)amino}propane{$Ph_2PNHCH(CH_3)CH_2NHPPh_2$}($L_2$), trans-1,2-bis{(diphenylphosphino)amino}cyclohexane{$Ph_2PNHC_6H_{10}NHPPh_2$}($L_3$) and 1,2-bis{(diphenylphosphino)amino}benzene{$Ph_2PNHC_6H_4NHPPh_2$}($L_4$). The properties of these complexes are characterized by optical spectroscopic methods including UV/vis spectroscopy, CD, IR, $^1H$- and $^{31}P-NMR$ together with conductometer and elemental analysis. All complexes are stable under atmospheric environment. Catalytic reactivity for C-C coupling between [$M(L)X_2$] and Grignard reagents(RMgX; R=phenyl, propyl, buthyl) by thermolysis were investigated utilizing GC/mass, $^1H$- and $^{13}C-NMR$. When mol scale is 1:20 at [$Pd(L)Cl_2$] and Grignard reagents, the high catalytic activity for C-C coupling is apparent. The [$M(L)X_2$](X=Cl, Br) complexes which have strong bond at M-P exhibit high yields for C-C coupling reactions. When the central metal ion is Pd(II), the high catalytic activity for C-C coupling is apparent. The complex coordinated with Br shows higher catalytic activity for C-C coupling reactions compared to Cl.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.666-672
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• 2011

The catalytic activity of an inorganic-organic complex with a vanadium-substituted polyoxometalate 1, formulated as [Cu(2,2'-bipy)]$[Cu(2,2'-bipy)_2]_2[PMo_8V_6O_{42}]{\cdot}1.5H_2O$ was studied in the Biginelli reactions. The obtained results showed that, in the one-pot synthesis of dihydropyrimidinones, the turnover frequencies (TOF) for the [Cu(2,2'-bipy)]$[Cu(2,2'-bipy)_2]_2[PMo_8V_6O_{42}]{\cdot}1.5H_2O$ catalyst were higher than the $H_3PMo_{12}O_{40}$ catalyst.

• Bulletin of the Korean Chemical Society
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• v.9 no.5
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• pp.292-295
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• 1988

Macrocyclic ligands have been studies as cation carriers in a bulk liquid membrane system. $Cu^{2+}$ has been transported using nitrogen substituted macrocycles as carriers and several transition metal ions($M^{n+}\;=\;Mn^{2+},\;Co^{2+},\;Ni^{2+},\;Cd^{2+},\;Pb^{2+}\;and\;Ag^{+}$) have been transported using $DBN_3O_2,\;DBN_2O_2,\;Me_6N_414C4$ and DA18C6 as carriers in a bulk liquid membrane system. Competitive $Cu^{2+}-M2^+$ transport studies have also been carried out for the same system. In single cation transport experiments, the best macrocyclic ligand for transport is a ligand that gives a moderately stable rather than very stable complex in the extraction. However, when both cations are present in the source phase, the cation which forms the most stable complex with carrier is favored in transport over other cations. Generally, the nitrogen substiituted macrocycles transport $Cu^{2+}$ selectively over $Mn^+$. Ligand structure, equilibrium constant (or stability constant) for complex formation, source phase pH and carrier concentration are also important parameters in transport experiments.

• Mycobiology
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• v.35 no.3
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• pp.150-153
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• 2007

New $N_2O_2$ donor type Schiff base has been designed and synthesized by condensing acetoacetanilido-4-aminoantipyrine with 2-aminobenzoic acid in ethanol. Solid metal complexes of the Schiff base with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, fast atom bombardment (FAB) mass, IR, UV-Vis, and $^1H$ NMR spectral studies. The data show that the complexes have the composition of ML type. The UV-Vis. and magnetic susceptibility data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The in vitro antifungal activities of the compounds were tested against fungi such as Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, Candida albicans, Rhizoctonia bataicola and Trichoderma harizanum. All the metal complexes showed stronger antifungal activities than the free ligand. The minimum inhibitory concentrations (MIC) of the metal complexes were found in the range of $10{\sim}31{\mu}g/ml$.