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CH3OH 용매에서 란탄족 원소{Ln(III)=Pr, Sm, Gd, Dy|}-거대고리 착물과 보조 리간드 간의 화학평형(제2보):주게원자가가 산소인 염기를 중심으로 고찰

Chemical Equilibria of Lanthanides{Ln=Pr,Sm,Gd,Dy}-Macrocyclic Complexes with Auxiliary Ligands in CH3OH(Part ll): Study of the Coordination of Oxygen-Containing Bases

대한화학회지 1999년 43권 6호 p.628 ~ 635
변종철, 박유철, 한충훈,
소속 상세정보
변종철 ( Byun Jong-Chul ) - Jeju National University Department of Chemistry
박유철 ( Park Yu-Chul ) - Kyungpook National University Department of Chemistry
한충훈 ( Han Chung-Hun ) - Jeju National University Department of Chemistry

Abstract

활성화된 Mn(IV)O2를 이용하여 2,6-bis(hydroxymethyl)-4-methylphenol로부터 2,6-difprmyl-p-cresol과 2-hydroxy-3-hydroxymethyl-5-methylbenzaldehyde를 제조하였다. 2-hydroxy-3-hydroxymethyl-5-methylbenzaldehyde와 ethylenediamine 및 1,3-diaminopropane의 축합반응에 의해 6-배위 칸막이 리간드, H4L[A]와 H4L[B]를 각각 얻었다. methanol에서 2,6-diformyl-p-cresol과 1,2-diaminobenzene으로부터 부분적으로 환원된 거대고리, H4[20]DOTA를 얻을 수 있었다. 이 H4[20]DOTA와 lanthanide(IlI) nitrate 간의 반응 또는 methanol에서 주형과정(template procedure)에 의해 일핵 착물, [Ln(IIl)(H2[20]DOTA)(ClO4)(H2O)] 3H2O과 [Ln([20]DOTA)(NO3)(H2O)](NO3)2·xH2O를 각각 합성하였다. [Ln([20]DOTA)(NO3)(H2O)](NO3)2 xH2O를 2일 정도 methanol에 정치함으로써 얻은 [Ln([20]DOTA)(NO3)(CH3OH)]2+에서 배위된 CH3OH이 주게원자가 O인 보조리간드, La(=salicylic acid, p-chlorobenzoic acid, benzoic acid, acetic acid, 4-bromophenol)에 의해 치환될 때 평형상수 (K)를 25℃, μ=0.1M NaClO4에서 분광학적 방법으로 결정하였다. 이 때 평형상수(K) 값들은 보조리간드 pKa 크기의 반대 경향인 salicylic acid>p-chlorobenzoic acid>benzoic acid>acetic acid>4-bromophenol 순서로 나타났다.

Direct preparative method of 2,6-diformyl-p-cresol and 2-hydroxy-3-hydroxy-5-methylbenzaldehyde from 2,6-bis(hydroxymethyl)-4-methylphenol using activated Mn(IV)O2, was described. Hexadentate compartmental Iigands, H4L[A] and H4L[B] were prepared by condensation reactions of 2-hydroxy-3-hydroxy methyl-5-methylbenzaldehyde with ethylenediamine and 1,3-diaminopropane respectively. By the reaction of macrocycle(H4[20]DOTA) with Ln(III) nitrate {Ln(III)=Pr, Sm, Cd, Dy }, discrete mononuclear Ln(III) complexes of the type [Ln(H2[20]DOTA)(Cl04)(H2O)]·3H20 were synthesized in the solid state. [Ln([20]DOTA)(N03)(H2O)](NO3)2·xH2O was placed in methanol for 2 days, and [Ln([20]DOTA)(N03)(CH30H)]2+ was formed, The equilibrium constants(K) for the substitution of coordinated CH3OH in the Ln-[20]DOTA complexes by various auxiliary ligand, La(=salicylic acid, p-chlorobenzoic acid, benzoic acid, acetic acid. 4-bromophenol) were determined spectroscopically at 25℃ and 0.1M NaCl04. The K values calculated were in the order of salicylic acid > p-chlorobenzoic acid > benzoic acic > acetic acid > 4-bromophenol, while pKa of auxiliary ligands was in the opposite trend.

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