• 대한화학회지
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• 제63권1호
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• pp.29-36
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• 2019

A potentially tetradentate Schiff base ligand, 2-((2-((pyridin-2-ylmethylene)amino)ethyl)amino)ethan-1-ol (PMAE), and its cadmium(II) complex, [$Cd(PMAE)I_2$] (1), were prepared and characterized by elemental analysis, FT-IR, Raman, $^1H$ and $^{13}C$ NMR spectroscopies and single-crystal X-ray diffraction. In the crystal structure of 1, the cadmium atom has a slightly distorted square-pyramidal geometry and a $CdN_3I_2$ environment in which the PMAE acts as an $N_3$-donor. In the crystal packing of the complex, the alcohol and amine groups of the coordinated ligands participate in hydrogen bonding with iodide ions and form $R^2{_2}(14)$ and $R^2{_2}(8)$ hydrogen bond motifs, respectively. In addition to the hydrogen bonds, the crystal network is stabilized by ${\pi}-{\pi}$ stacking interactions between pyridine rings. The thermodynamic stability of the isolated ligand and its cadmium complex along with their charge distribution patterns were studied by DFT and NBO analysis.

• 대한화학회지
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• 제32권5호
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• pp.464-475
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• 1988

Fe(Ⅲ) 및 Mn(Ⅱ)과 p-aminoazobenzene 및 그 유도체가 반응하여 형성된 착물들에 대하여 가시-자외선 및 적외선 분광광도법과 전기전도도방법을 이용하여 용매의 효과, donor의 염기도와 착물형성에 미치는 영향을 조사하였다. 그 결과 착물의 조성비, 안정도 상수 및 몰흡광계수를 구하여 van't Hoff식으로부터 ${\Delta}H^{\circ}$, ${\Delta}G^{\circ}$ 및 ${\Delta}S^{\circ}$를 계산하였으며 반응성과 등속도관계를 고려하여 반응속도와 평형조절인자를 알게 되었다.

• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.2045-2050
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• 2007

The reactions of mercury(II) chloride with O3S2-donor macrocyclic ligands with (L1) and without (L2) dibenzosubunit afforded respective exo- (1) and endo-coordinated (2) complexes depending on the ring rigidity of the ligands. From the X-ray crystal structures and comparative NMR studies for the complexes 1 and 2, it is confirmed that the resulting species with different coordination modes exist not only in solid state but also in solution state.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.23-27
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• 1997

The luminescence and excitation spectra of [Cr(trans-diammac)](ClO4)3 (trans-diammac=trans-6, 3-dimethyl-l, 4, 8, 11-tetraazacyclotetradecane-6, 13-diamine) taken at 77 K are reported. The mid and far-infrared spectra at room-temperature are also measured between 4000 cm-1and 50 cm-1. In the excitation spectrum the 2Eg components are splitted by 102 cm-1. Using the observed electronic transitions, a ligand field analysis was performed to determine more detailed bonding properties of the coordinated atoms toward chromium(Ⅲ). According to the results, we can confirm that the six nitrogen atoms have a strong σ-donor character, and the trans-diammac secondary amine has a greater value of eσ than does the primary amine.

• Bulletin of the Korean Chemical Society
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• 제10권2호
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• pp.138-142
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• 1989

Three oxovanadium(IV) complexes with bidentate ligands having only oxygen donor atoms, benzohydroxamic acid (Hben), 8-hydroxyquinoline-N-oxide(Hhqno) and picolinic acid-N-oxide (Hpicn) are prepared and magnetic and spectroscopic properties are investigated for the complexes $VO(ben)_2,\;VO(hqno)_2\;and \;VO(picn)_2.$ Magnetic data together with IR results strongly indicate that dimeric intermolecular interaction is significant in $VO(ben)_2$ while the presence of polymeric V-O${\cdot}{\cdot}$V-O interaction is suggestive in $VO(picn)_2$. For all three complexes, three electronic d-d transitions were observed; extremely strong optical absorption of these bands of $VO(ben)_2$ in DMSO are supposed to be arised from a great metal-ligand covalency. Some fundamental vibration modes of oxovanadium(IV) complexes were empirically assigned from the differences in the spectrum of metal complexes with free ligand.

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.436-440
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• 1999

The highly resolved absorption spectra of mer-[Cr(dpt)(Gly-Gly)]ClO4·H2O [dpt = di(3-aminopropyl)amine, H2Gly-Gly = glycylglycine] have been measured between 13000 cm-1 and 50000 cm-1 temperatures down to 2 K. The vibrational intervals were extracted by recording emission and far-infrared spectra. The characteristic infrared bands in meridional isomer were discussed. The four-teen electronic origins due to spin-allowed and spin-forbidden transitions were assigned. With the use of this electronic transitions, a ligand field optimization based on the exact known ligand geometry have been performed to determine more detailed bonding properties of Gly-Gly and dpt ligands. It is confirmed that the peptide nitrogen of the Gly-Gly has a weak π-donor property toward chrornium(Ⅲ) ion.

• 대한화학회지
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• 제57권6호
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• pp.726-730
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• 2013

Complexes synthesized by reacting alkyl and aryl phosphines with different transition metals are of great interest due to their catalytic properties. Many of the phosphine complexes are soluble in polar solvents as a result they find applications in homogeneous catalysis. In our present work we report, four transition metal complexes of Ni(II), Pd(II), Pt(II) and Ru(II) with an asymmetrical ditertiaryphosphine ligand. The synthesized ligand bears a less electronegative substituent such as methyl group on the aromatic nucleus hence makes it a strong ${\sigma}$-donor to form stable complexes and thus could effectively used in catalytic reactions. The complexes have been completely characterized by elemental analyses, FTIR, $^1HNMR$, $^{31}PNMR$ and FAB Mass Spectrometry methods. Based on the spectroscopic evidences it has been confirmed that Ni(II), Pd(II) and Pt(II) complexes with the ditertiaryphosphine ligand showed cis whereas the Ru(II) complex showed trans geometry in their molecular structure.

• 대한화학회지
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• 제60권5호
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• Macromolecular Research
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• 제14권5호
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• pp.539-544
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• 2006

2-Furancarboxaldehyde-2-pyridinylhydrazone (FPH) and 5-methyl-2-furancarboxaldehyde-2-pyridinylhydrazone (MFPH) were synthesized and used as tridentate ligands of copper (I) bromide for the atom transfer radical polymerization of methyl methacrylate (MMA) and styrene. The polymerization of methyl methacrylate achieved high conversion and yielded polymers with a good control of molecular weight and low polydispersity (PDI=1.33). Higher PDI were observed in the polymerization of styrene. Using 1-phenyl ethylbromide (PEBr) and ethyl 2-bromoisobutyrate (EBiB) as model compounds for the polymeric chain ends, the activation rate constants of the new catalytic systems were measured. These results were correlated with the polymerization results and compared with another catalytic system previously reported.

• Bulletin of the Korean Chemical Society
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• 제17권5호
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• pp.433-436
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• 1996

Cobalt(Ⅲ) complexes of trifunctional amino acid and N,N'-diethylethylenediamine-N,N'-di-α-butyrate(deedba), s-cis-[Co(deedba)(L-aa)] (L-aa=S-methyl-L-cysteine, L-aspartic acid, L-glutamic acid) have been prepared from the reaction between the s-cis-[Co(deedba)(Cl2)]- complex and the corresponding amino acid. The amino acids have been found to coordinate through the amine and carboxylate groups. The S-methyl-L-cystene is coordinated not by the sulfur donor atom, but by the nitrogen and oxgen donor atoms, and the L-aspartic and L-glutamic acids are coordinated to the cobalt(Ⅲ) ion via formation of the five-membered glycinate chelate ring. Relatively small optical activity shown by the complexes is due to the chiral center present in the amino acids.