• Title/Summary/Keyword: transition metal

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A Complexation Study of Novel Triaza and Hexaaza Macrocycles for the Use of Analytical Reagents

  • Wakita, Hisanobu;Yamaguchi, Toshio;Matsuki, Yuuichi;Kurisaki, Tsutomu
    • Analytical Science and Technology
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    • 제8권4호
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    • pp.449-456
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    • 1995

  • Novel macrocyclic ligands modified with pendant arms, N, N', N'', N''', N'''', N'''''-hexakis(2-aminoethyl)-1, 4, 7, 10, 13, 16-hexaazacyclootadecane [$L_3$, Fig.1] and 1, 4, 7-tris(3-(o-hydroxyphenyl)propyl)-1, 4, 7-triazacyclononane [$L_4$, Fig.1] have been synthesized, and the protonation of $L_3$ and $L_4$ and stability constants of $L_3$ with bivalent transition metal ions and rare earth metal ions were determined by a potentiometry. The obtained results show that the complex formation of $L_3$ depends on the metal ligand ratios, and the stability of the metal complexes does not depend on the sizes of the metal ions, but on the nature of the metal ions. The structures of the rare earth complexes for $L_4$ were characterized by an X-ray absorption spectrometry(XAFS).

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Voltammetric Studies of Diazocalix[4]crown-6 for Metal Ion Sensing

  • Dong, Yun-Yan;Kim, Tae-Hyun;Lee, Chang-Seuk;Kim, Hyun-Jung;Lee, Jae-Hong;Lee, Joung-Hae;Kim, Ha-Suck;Kim, Jong-Seung
    • Bulletin of the Korean Chemical Society
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    • 제31권12호
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    • pp.3549-3552
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    • 2010

  • The complex formation between diazocalix[4]dipropyl (1) and diazocalix[4]crown-6 ether (2) with alkali, alkaline earth and transition metal ions was investigated by voltammetry. Electrochemical properties of compounds 1 and 2 and their selectivity toward metal ions were evaluated in $CH_3CN$ solution by comparison of voltammetric behaviors of two phenols in each compound. Compounds 1 and 2 showed almost same voltammetric behavior which is two irreversible oxidation peaks caused by intramolecular hydrogen bonding between two phenols in 1 and 2. While, however, upon interacting with various metal ions, 1 with two propyl ether groups showed no significant changes in voltammetry, 2 with crown ether group caused significant voltammetric changes upon the addition of $Ba^{2+}$ to 2. Their behavior is closely related to the complex formation by entrapment of metal ion into crown ether cavity, and ion-dipole interaction between metal ion and two phenolic groups in calix[4]crown-6.

  • https://doi.org/10.5012/bkcs.2010.31.12.3549 인용 PDF KSCI

Electrical Properties of Molybdenum Metal Deposited by Plasma Enhanced - Atomic Layer Deposition of Variation Condition (다양한 조건의 플라즈마 원자층 증착법으로 증착된 Mo 금속의 전기적 특성)

  • Lim, Taewaen;Chang, Hyo Sik
    • Korean Journal of Materials Research
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    • 제29권11호
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    • pp.715-719
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    • 2019

  • Molybdenum is a low-resistivity transition metal that can be applied to silicon devices using Si-metal electrode structures and thin film solar cell electrodes. We investigate the deposition of metal Mo thin film by plasma-enhanced atomic layer deposition (PE-ALD). $Mo(CO)_6$ and $H_2$ plasma are used as precursor. $H_2$ plasma is induced between ALD cycles for reduction of $Mo(CO)_6$ and Mo film is deposited on Si substrate at $300^{\circ}C$. Through variation of PE-ALD conditions such as precursor pulse time, plasma pulse time and plasma power, we find that these conditions result in low resistivity. The resistivity is affected by Mo pulse time. We can find the reason through analyzing XPS data according to Mo pulse time. The thickness uniformity is affected by plasma power. The lowest resistivity is $176{\mu}{\Omega}{\cdot}cm$ at $Mo(CO)_6$ pulse time 3s. The thickness uniformity of metal Mo thin film deposited by PE-ALD shows a value of less than 3% below the plasma power of 200 W.

  • https://doi.org/10.3740/MRSK.2019.29.11.715 인용 PDF KSCI