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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 42, Number 4
JKCSEZ 42(4)
August 20, 1998 

Synthesis of Tridentate-Schiff Base Co(II) Complexes and Their Electrochemical Properties

세자리 Schiff Base Co(II) 착물의 합성과 전기화학적 성질
Hee-Nam Chae, Yong-Kook Choi

Salicyladehyde와 2-hydroxy-1-naphthaldehyde를 2-aminophenol과 2-amino-p-cresol에 반응시켜 세자리 Schiff base 리간드(SIPH2, SIPCH2, HNIPH2, HNIPCH2)들을 합성하였으며 이들 리간드를 Co(Ⅱ) 이온과 반응시켜 세자리 Schiff base Co(Ⅱ) 착물들을 합성하였다. 리간드와 착물들의 구조와 특성을 원소분석, 1H-NMR, IR, UV-vis 분광법과 열 무게 분석법으로 예측하였다. Co(Ⅱ) 착물들은 Schiff base 리간드와 금속(Ⅱ)의 몰비가 1:1로 결합하였으며, 3분자의 수화물이 배위된 6배위 착물 구조임을 알았다.지지 전해질로서 0.1M TBAP를 포함한 DMSO 용액에서 순환 전압전류법으로 세자리 Schiff base 리간드와 이들의 Co(Ⅱ) 착물들의 전기 화학적인 산화·환원 과정을 알아보았다. 리간드들의 전기 화학적 환원은 확산 지배적이고 비가역적으로 진행되었으며 Co(Ⅱ) 착물의 전기 화학적 환원과정은 2단게의 1전자 반응으로 확산 지배적이고 비가역적으로 진행되었다. Co(Ⅱ) 착물들의 환원전위는 [Co(Ⅱ)(HNIPC)(H2O)3]>[Co(Ⅱ)(HNIP)(H2O)3]>[Co(Ⅱ)(SIPC)(H2O)3]>[Co(Ⅱ)(SIP)(H2O)3] 순으로 약간 양전위 방향으로 이동하였으나 리간드의 영향은 크게 받지 않았다.

Tridentate Schiff base ligands such as SIPH2, SIPCH2, HNIPH2, and HNIPCH2 were prepared by the reaction of salicylaldehyde and 2-hydroxy-l-naphthaldehyde with 2-aminophenol and 2-amino-p-cresol. The structures and properties of ligands and their Co(Ⅱ) complexes were investigated by elemental analysis, 1HNMR, IR, UV-visible spectra, and thennogravimetric analysis. The molar ratio of Schiff base to the metal of complexes was found to be 1:1. Co(Ⅱ) complexes were contemplated to be hexa-coofdinated octahedral configuration containing three water molecules. The redox process of ligands and complexes in DMSO solution containing 0.1 M TBAP as a supporting electrolyte were investigated by cyclic voltammetry with glassy carbon electrode. The redox process of the tridentate Schiff base ligands was totally irreversible. The redox process of Co(Ⅱ) complexes were irreversible and one electron processes by two steps in diffusion controlled reaction. The reduction potential of the Co(Ⅱ) complexes was shifted to the positive direction in the order [Co(Ⅱ)(HNIPC)(H2O)3] > [Co(Ⅱ)(HNIP)(H2O)3] > [Co(Ⅱ)(SIPC)(H2O)3] > [Co(Ⅱ)(SIP)(H2O)3], and their dependence on ligands were not so high.

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