• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.76.2-76.2
• /
• 2013

Advanced electronic application areas have strongly required new materials due to the continuous shrinking dimensions of their devices. Specially, the development and use of metal precursors for atomic layer deposition has been extensively focused on application to electronic devices. Thus the systematic design and synthesis of metal compounds with relevant chemical and physical properties, such as stability, volatility, and resistance to air and moisture are very important in the vacuum deposition fields. In many case, organic ligands for metal precursors are especially focused in the related research areas because the large scale synthesis of the metal complexes with excellent properties exclusively depends on the potential usefulness of the ligands. It is recommended for metal complexes to be in monomeric forms because mononuclear complexes generally show high vapor pressures comparing with their oligomeric structure such as dimer and trimer. Simple metal alkoxides complexes are involatile except several examples such as Ti(OiPr)4, Si(OEt)4, and Hf(OtBu)4. Thus the coordinated atom of alkoxide ligands should be crowded in its own environment with some substituents by prohibiting the coordinated atoms from bonding to another metal through oxygen-bridging configuration. Alkoxide ligands containing donor-functionalized group such as amino and alkoxy which can induce the increasing of the coordinative saturation of the metal complexes and the decreasing of the intermolecular interaction between or among the metal compounds. In this presentation, we will discuss the development of metal compounds which adopted donor-functionalized alkoxide ligands derived from their alcohols for electronic application. Some recent results on ALD using metal precursors such as tin, nickel, ruthenium, and tungsten developed in our group will be disclosed.

• Journal of the Korean Chemical Society
• /
• v.36 no.6
• /
• pp.802-811
• /
• 1992

The conformations of several carbene-olefin-transition metal complexes[$(CO)_4M$-(CHX)olefin] (X: $OCH_3,\;NHCH_3,\;SCH_3$, M: C, Mo, W) have been studied by means of Extend Huckel calculations. In the case of $d^6$ transition metal octahedral complexes, it is shown that the two main factors which determine the optimal conformation are metal-to-ligand back-donation and direct ligand-ligand interaction at the metal, but the ligand-ligand interaction dominates the situation for a metal that is coordinated to $\pi$ acceptor ligands and to $\pi$ donor group on the carbene. The relative amounts of both factors depend strongly on the electronic nature of the ligands at the metal. The greater electron donating ability of nitrogen stabilizes amino-substituted carbene complexes compared with their alkoxyl substituted analogues. This interaction is optimal when the $\pi$ systems of the carbene and olefin are coplanar. The introduction of the $\pi$ donor group on the carbene carbon increases also the importance of the ligand-ligand interaction.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.3
• /
• pp.393-398
• /
• 2005

The stability constants for the diaza-18-crown-6 ethers 2-6 and alkali metal cations ($Na^+,\;K^+,\;Rb^+\;and\;Cs^+$) were determined using potentiometry in 95% methanol. For each metal ion the stability constants of the partiallyfluorinated ligands 3-6 were larger than that of the non-fluorinated ligand 2, which might reflect an interaction between fluorine atoms and alkali metal cations. The stability constant of the ligand 4 was larger than that of the ligand 5 for each metal cation tested. This finding was also supported by the results of cation-induced chemical shifts in $^1H-,\;^{19}F$-NMR and extraction experiment. The potentiometry and NMR results as well as the X-ray crystal structures revealed that the position and number of fluorine atoms in the benzyl side arms was crucial for the enhanced interaction between a ligand and an alkali metal.

• Journal of the Korean Chemical Society
• /
• v.43 no.2
• /
• pp.167-171
• /
• 1999

An investigation of the interaction of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Ag(I) with two N,N'-dibenzylated nitrogen-oxygen mixed donor macrocyclic ligands, has been carried out. Tle log K values for the respective complexes in 95% methanol have been determined potentiometrically. Both ligands have formed stable complex with only Cu(II) and Ag(I) ion. Transport measurements in a bulk liquid membrane system exhibited a very high selectivity of Ag(I) ion over the other metal ions used.

• Bulletin of the Korean Chemical Society
• /
• v.10 no.2
• /
• pp.138-142
• /
• 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
• /
• v.10 no.6
• /
• pp.515-521
• /
• 1989

The molecular interaction of $W_2(NH_2)_4Cl_4$ fragment with chlorine ligands has been studied by means of extended Huckel calculations. We have extended the Huckel calculation to unknown edge-sharing $W_2(NH_2)_4Cl_4({\eta}-X)_2$ complexes (X = CO, H) in order to compare the stability of the complexes. The calculations showed that the size and electronic property of bridged ligand are important in determining the stability. The stabilities of the related metal-metal bonded edge-sharing complexes are discussed.

• Journal of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.331-339
• /
• 1990

It has been studied that relations between electronic structure and anti-tumor activity by variation of amine group in cis-diamminedichloroplatinum (Ⅱ) complexes. We were also interested in these Pt (Ⅱ) complexes interaction with 1-methylcytosine of DNA base and the electronic structure of these complexes in order to understand the mechanism of the metal-nucleobases interaction. The results showed that net charge of center metal in Pt complexes effect anti-tumor activity. The mechanisgm of the bonding between metal and ligands largely based on charge transfer from ligand to metal atom. Furthermore, the established molecular orbitals showed that metal 6p-orbitals played an important role in the bonding scheme for the interactions between platinum (Ⅱ) complexes and 1-methylcytosine. We also found that the stronger Pt-N3 bonding strength became, the better anti-tumor agents were.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.6
• /
• pp.809-812
• /
• 2004

Complexation reactions of nitrilotriacetate (NTA) and penicillamine with $Cu^{2+}$ and $Co^{2+}$ have been studied in solution phase using paper electrophoresis technique. The stability constants of the complexes Cu(II)-nitrilotriacetate-penicillamine and Co(II)-nitrilotriacetate-penicillamine have been found to be $6.64{\pm}0.03\;and\;5.86{\pm}0.05$ (logarithm stability constant values), respectively at 35$^{\circ}C$ and ionic strength 0.1 M.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.219-224
• /
• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.

• Bulletin of the Korean Chemical Society
• /
• v.1 no.3
• /
• pp.105-109
• /
• 1980

A general spectroscopic method is described for studies on the complex formation between metal ions and ligands, and is applied to $Cu^{2+}$ and $Ca^{2+}$binding to glycosaminoglycans. The order of binding constants for both ions is heparin >dermatan sulfate >chondroitin sulfate. The electrostatic forces are shown to be the predominant factor in the interaction. The 2- to 3-fold higher affinity for $Cu^{2+}$ than for $Ca^{2+}$ is obtained for heparin and dermatan sulfate, but little difference for chondroitin sulfate. These results are explained as chelation of both carboxyl and sulfate groups to $Cu^{2+}$ in former cases. The difference of binding constants among glycosaminoglycans is related to proposed various biological functions of the biopolymers.