• 한국결정성장학회지
• /
• 제31권2호
• /
• pp.69-72
• /
• 2021

The reaction of ammonium ferric sulfate with sodium borohydride in laponite sol yields nanoiron colloidal solution. This solution in air forms transparent yellow brown solution. The resulting solution reacts with bidentate chelating ligands. The reaction products are characterized by UV-Vis absorption spectroscopy and X-ray diffraction. All compounds show metal to ligand charge transfer band in the region of 400~650 nm in UV-Vis absorption spectra. This indicates the formation of iron-ligand complex by air oxidation of nanoiron. Also, XRD patterns exhibit that the iron-ligand complex is intercalated in the interlayer of laponite.

• 한국결정성장학회지
• /
• 제17권4호
• /
• pp.139-144
• /
• 2007

2자리 리간드를 사용하여 $BaWO_4$ 결정을 합성하였다. 리간드의 농도와 $[{WO_4}^{2-}]/[Ba^{2+}]$ 비율과 같은 반응 변수는 다양한 형태의 $BaWO_4$ 결정을 형성하는데 매우 중요한 역할을 한다. TMEDA를 리간드로 사용했을 때는 250nm의 폭과 $2{\sim}3{\mu}m$의 길이를 가진 십자형의 단면들의 자기 조립에 의해서 $15{\sim}20{\mu}m$ 길이의 마이크로 막대형의 $BaWO_4$ 결정을 얻었다.

• Bulletin of the Korean Chemical Society
• /
• 제35권1호
• /
• pp.269-272
• /
• 2014

• Bulletin of the Korean Chemical Society
• /
• 제30권5호
• /
• pp.1204-1206
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• 제26권1호
• /
• pp.72-76
• /
• 2005

Some mononuclear oxovanadium(IV) complexes having the general formula [VOL(bidentate)] (1-4) of which L is tridentate ONS-donor salicylaldehyde S-methyldithiocarbazate (sal-mdtc$^{2-}$) or salicylaldehyde 4- phenylthiosemicarbazate (sal-phtsc$^{2-}$) and bidentate stands for 2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen) have been synthesized. The complexes were characterized by elemental analyses, FAB mass, UV, IR spectroscopy, and cyclic voltammetry. Two of the complexes [VO(sal-mdtc)(bpy)] (1) and [VO(sal-mdtc) (phen)] (2) were crystallographically characterized. The structures revealed that vanadium atom is octahedrally coordinated by the O, N, and S donor atoms of the tridentate ligand, the two N atoms of bidentate ligand, and the oxo atom. The oxygen donor, occupying an apical position has a trans-labilizing effect, resulting in elongation of the V-N bond. The cyclic voltammograms of the complexes exhibited one cathodic response in the range −d1.45 $\sim$ −f1.52 V due to the reduction of V(IV) to V(III).

• Bulletin of the Korean Chemical Society
• /
• 제18권4호
• /
• pp.406-409
• /
• 1997

The various cobalt(Ⅱ) complexes were synthesized and characterized using tris-(2-benzimidazolylmethyl)amine (ntb) as a ligand where the ntb plays as a tripodal tetradentate ligand to form complexes with a trigonal pyramidal geometry. The complexes have 5 and 6 coordinate cobalt(Ⅱ) ions depending on the additional ligand used. In each complex the additional ligand, chloride anion, or acetate anion occupies the "open" site trans to the apical tertiary nitrogen atom of ntb ligand. Complex 1, [Co(Ⅱ)(ntb)Cl]Cl has a trigonal bipyramidal geometry. This geometry was easily constructed using ntb as a tetradentate ligand and chloride as a monodentate ligand. The complex is isostructural to the corresponding manganese(Ⅱ) complex. Crystal data are as follows: [Co(Ⅱ)(ntb)Cl]Cl·MeOH, 1. triclinic space group P1; a=13.524(2) Å, b=14.037(2) Å, c=17.275(1) Å; α=78.798(9), β=84.159(8)°, γ=65.504(9)°; V=2929.6(6) Å3; Z=4; R1=0.0715, wR2=0.1461 for reflections of I > 2σ(I). Six coordinate complex 2 [Co(ntb)(OAc)](OAc) was synthesized using ntb as a tetradentate ligand and acetate as a bidentate chelating ligand.

• 공업화학
• /
• 제10권7호
• /
• pp.1079-1085
• /
• 1999

본 연구에서는 여러 가지 균일계 전이 금속 촉매를 사용하여 니트로벤젠을 아닐린 및 일산화탄소와 반응시켜 N,N'-디페닐우레아(DPU)를 생성하는 반응에 있어서 촉매와 리간드 및 promrter가 반응에 미치는 영향을 고찰하였다. 촉매로서는 Pd, Ni, Pt, Ru, Rh, 그리고 Fe 화합물을 이용하였고 리간드로서는 monodentate 리간드인 $PPh_3$와 bidentate 리간드인 1,3-bis(diphenylphosphino)proane(dppp)를 사용하여 효과를 비교하였다. Promoter로서는 $Et_4NCl$을 사용하였다. Pd 및 Ni 촉매는 니트로벤젠, 아닐린, 그리고 일산화탄소로부터의 DPU 합성에 매우 효과적이었고 상대적으로 온화한 조건에서도 거의 정량적인 수율로 DPU를 합성할 수 있었다. 이 경우 바이덴테이트 리간드인 dppp는 모노덴테이트 리간드인 $PPh_3$에 비하여 반응 속도가 훨씬 빠르고 니트로벤젠에 대한 아닐린의 소모량이 훨씬 적었는데 이는 리간드인 cis coordination에 기인하는 것으로 추정된다. $PPh_3$ 리간드인 경우에는 $Et_4NCl$ 조촉매의 사용이 필수적인데 비하여 dppp인 경우에는 오히려 조촉매가 반응 속도를 저해하였다. Pd-dppp 촉매계는 촉매의 재사용이 가능하나 촉매가 서서히 비활성화 됨을 알 수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제16권5호
• /
• pp.439-443
• /
• 1995

Both enantiomers of (S)-(-)-2-(diphenylphosphino)-2'-mercapto-1,1'-binaphthyl and their derivatives were obtained by synthesis from racemic 2,2'-dihydroxy-1,1'-binaphthyl and subsequent resolution. The utilities of these ligands were investigated briefly. And among these, S-methyl derivative 15 has proved to be an effective ligand for Pd-catalyzed allylic alkylation.

• Bulletin of the Korean Chemical Society
• /
• 제32권1호
• /
• pp.296-298
• /
• 2011

• Bulletin of the Korean Chemical Society
• /
• 제29권3호
• /
• pp.627-640
• /
• 2008

The geometrical structures, atomic charges, and relative energies of tetracoordinated Pd complexes [PdCl3Z (Z = Cl-, Br-, OH?-, H2O, NH3, PH3), PdCl2Z2 (Z = Br-, OH?-, H2O, NH3, PH3), PdZ?2X (Z = Cl-, OH?-, H2O, NH3, PH3; X = oxalate, O2-?CCO2-), and PdZ2Y (Z = Cl?-, OH?-, H2O, NH3, PH3; Y = succinate, CO2-?CHCHCO2-?)] and the ligand exchange reactions of the Pd complexes were investigated using the ab initio second order Mller-Plesset perturbation (MP2) and Density Functional Theory (DFT) methods. The geometrical characteristics of the tetracoordinated Pd(II) complexes with mono- and bidentate ligands, the effects of the atomic charges for the charged and uncharged ligands, the (dz2-p ) interactions between the dz2-orbital of Pd(II) and the p -orbital of bidentates, and the relative stabilities between the isomers of PdCl2Z2 and PdZ2Y were investigated in detail. The potential energy surfaces for the ligand exchange reactions used for the conversions of {[PdCl2(NH3)2] + H2O} to {[PdCl(NH3)2(H2O)]+ + Cl?-?} and {[PdCl2(PH3)2] + H2O} to {[PdCl(PH3)2(H2O)]+ + Cl?-?]} were investigated. The geometrical structure variations, molecular orbital variations (HOMO and LUMO), and relative stabilities for the ligand exchange processes were also examined quantitatively.