• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.194-199
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• 2000

The chemical behavior for Mo(0) and W(0) complexes, [M(CO)$_2$(PPh$_3$)$_4$] (M=Mo and W),has been investigated by UV-vis spectroscopic, magnetic, and electrochemical methods. Three absorption bands are observed in the UV-spectra. The crystal-field-splitti ng energy, spin-pairing energy, and bond strengths were deduced from the spectra. The metal d electrons in both complexes seemed to be delocalized in low-spin state.Metal ligand correlation appeared to strongly depend on bond strengths and diamagnetic properties. In electrochemical processes, both complexes exhibit an irreversible reduction wave.

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.10-15
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• 2000

Compound trans-[FeH(NCS(i-Pr)-S)(dppe)₂](1) reacted with isopropyl iodide (i-PrI) to give an Fe(II)-organic isothiocyanide complex, trans-[FeH(NCS(i-Pr)-S)(dppe)₂]I (2). Compound 2 was structurally characterized, in which the hydride ligand appears to be involved in the "dihydrogen" bonding, M-H…H-C. Crystallographic data for 2: monoclinic space group P2₁/n, a=13.490(2)Å, b=17.269(3)Å, c=21.384(3)Å, β=90.682(7)°, Z=4, R(wR₂)=0.0348(0.0894).

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.60-64
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• 2003

The reactions of $[Pt(dppf)Cl_2]$ with thiophenol (PhSH), 1-propanethiol (n-PrSH), and 1,3-propanedithiol $(HSCH_2CH_2CH_2SH)$ gave the corresponding Pt-dppf-di(thiolato) compounds, $[Pt(dppf)(SPh)_2]\;(1),\;[Pt(dppf)(S-n-Pr)_2]\;(2),\;and [Pt(dppf)(SCH_2CH_2CH_2S)]\;(3)$, respectively. All products are monomeric and 4-coordinate square-planar compounds and were structurally characterized by X-ray diffraction. Electrochemical measurements (cyclovoltammograms) revealed that the oxidation potential of the dppf ligand appears to depend on the type of the group on the thiolato ligand.

• Korean Journal of Crystallography
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• v.11 no.2
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• pp.80-83
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• 2000

Compound [Ni(P(OEt)3)4] (1) reacted with bis(diphenylphosphino)ethane (Ph2PCH2CH2Ph2, dppe) to give bis(bis(diphenylphosphine)ethane)nickel(0), [Ni(dppe)2] (2). Compound 2 was characterized by spectroscopy (1H-and 31P{1H}-NMR) and X-ray crystallography. Crystallographic data for 2: monoclinic space group P21/n, a=9.826(1)Å, b=21.167(2)Å, c=21.425(2)Å, β=91.957(9)°, Z=4, R(wR2)=0.0377(0.0882).

• Advances in materials Research
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• v.3 no.3
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• pp.175-183
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• 2014

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide ($MePPh_3I$) by Wittig reaction ($0^{\circ}C$ for 2 hrs, $N_2$ atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer ($180^{\circ}C$ for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.73-81
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• 1999

This paper was intended to evaluate the effect of the blending condition of pigments on the packing structure of coating color and the interaction between pigments and latices on the optical and interior properties of coated paper. It has been studied many ways to modify the coating structure to induce the interaction among coating components as followings ; 1) to use dispersant for pigment, 2) to control the charge density and the type of surface charge of latex, 3) to support the water retention by adding water retention agent or flow modifier. This paper was performed through the introduction of interaction between pigments which were two kinds of clays and one precipitated calcium carbonate(PCC) and ionic latices of which anionic and amphoteric respectively under the certain blending condition of pigments where their blending ratio of clays to calcium carbonate was 70pph to 30pph. The reason is that packing volume of pigments was highest in that region and thixotropical behavior appears in measuring rheology of coating color. We measured the properties of coating color, interaction with pigments and latex, and properties of coated paper and its printability. As a results, we could find out that amphoteric latex had a great influence on the interaction with pigments, especially clays, no matter what grade and also affected the coating structure significantly in case that this blending condition was 70(clays) to 30(PCC). It produced a powerful effect on the forming of bulky and smooth coating structure and in turn improved the printability of coated paper.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1920-1926
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• 2008

We investigated the C-H bond activation mechanism of aldimine by the [RhCl$(PPH_3)_3$] model catalyst using DFT B3LYP//SBKJC/6-31G*/6-31G on GAMESS. Due to their potential utility in organic synthesis, C-H bond activation is one of the most active research fields in organic and organometallic chemistry. C-H bond activation by a transition metal catalyst can be classified into two types of mechanisms: direct C-H bond cleavage by the metal catalyst or a multi-step mechanism via a tetrahedral transition state. There are three structural isomers of [RhCl$(PH_3)_2$] coordinated aldimine that differ in the position of chloride with respect to the molecular plane. By comparing activation energies of the overall reaction pathways that the three isomeric structures follow in each mechanism, we found that the C-H bond activation of aldimine by the [RhCl$(PH_3)_3$] catalyst occurs through the tetrahedral intermediate.

• Bulletin of the Korean Chemical Society
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• v.23 no.6
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• pp.845-851
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• 2002

The synthesis of the intramolecular donor - stabilized silyl and germyl complexes of the type ($Cab^c.p) MMe_2X$ (2a:M=Si, X=Cl;2b;M= Ge, X=Cl;2e;M=Si,X=H) was achieved by the reaction of $LiCab^c,p$ (1) with $Me_2SiClX$ and $Me_2GeCl_2$ respectively. The intramolecular M←P interacion in 2a-2c is provided by $^1H$, $13^C.$, $31^P$ and $29^Si$ NMR spectroscopy. The salt elimination reactions of dichlorotetramethyldisilane and -digermane with 1 afforded the $bis(\sigma-carboranylphosphino)disilane$ and disgermane [$(Cab^C.P)MMe_2]_2(4a;M$ = Si;4b: M=Ge). The oxidative addition reaction of 4a-4b with $pd_2(dba)_3CHCl_3afforded$ the bis(silyl)-and bis(germyl)-palladium complexes. The chloro-bridged dipalladium complexes were obtained by the reaction of 2a-2b with $pd_2(dba)_3CHCl_3$ The crystal structures of 5a and 7b were determined by X-ray structural studies.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.679-682
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• 2009

Utilizing a planar five coordinating N3S2 ligand, 2,6-bis(2-methylthiophenyliminomethyl)pyridine, a pseudo 7-coordinated manganese(II) complex with two labile triflate anions in the axial positions was synthesized. The reaction of the manganese(II) complex with an oxidant, iodosylbenzene, produced a metastable high-valent manganese(IV)-oxo species at 0 ${^{\circ}C}$. The high-valent Mn(IV)-oxo intermediate was characterized with a UV-vis spectrophotometer and an electrospray ionization mass spectroscopy. Reactivity studies of the Mn(IV)=O species revealed that the intermediate is capable of oxygenating $PPh_3$ and N-dealkylating N,N-dimethyl-toludine.

• Polymer(Korea)
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• v.31 no.3
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• pp.221-227
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• 2007

The mechanical properties and morphologies of lyocell and its blend we compared. Poly (vinyl alcohol) (PVA) was used as a filler in blends with lyocell produced through solution blending. The variations of their properties with polymer matrix filler content are discussed. The ultimate tensile strength of the PVA/lyocell blend is highest for a blend lyocell content of 30 wt%, and decreases as the lyocell content is increased up to 40 wt%. The variations in the initial moduli of the blends with filler content are similar. Lyocell and its blended hybrid films were prepared by the solution intercalation method, using dodecyltriphenylphosphonium-mica ($C_{12}PPh$-Mica) as the organoclay. The variations of the mechanical tensile properties of the hybrids with the organoclay content were examined. These properties were found to be optimal for an organoclay content of up to 5 wt%. However, the mechanical tensile properties of the PVA/Lyocell (w/w=30/70) blended hybrid films were found to decrease linearly with increases in organoclay content from 1 to 5 wt%.