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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 39, Number 6
JKCSEZ 39(6)
December 20, 1995 

 
Title
Complex Formation of Substituted Benzo-1,4,7,10,13-pentaoxacyclopentadecane (B15C5) with Nd(Ⅲ)

Nd(Ⅲ)과 치환된 Benzo-1,4,7,10,13-pentaoxacyclopentadecane (B15C5) 와의 착물 형성에 관한 연구
Author
Hae-Joong Kim, Jeong Kim, Si-Joong Kim

김해중, 김정, 김시중
Keywords
Abstract
메탄올 용액에서 Nd(Ⅲ)과 B15C5(benzo-1,4,7,10,13-pentaoxacyclopentadecane)의 치환체들간의 착물형성에 따른 화학적 조성비 및 온도변화에 따른 안정도상수, 열역학적 파라메타들을 분광광도법과 전기전도도법을 이용하여 결정하였다. 이때 B15C5의 치환기들은 CH3, Br, CHO, NO2 및 3,4-(NO2)2이었다. 메탄올 용액에서 Nd(Ⅲ)과 이들 리간드와의 착물의 조성비는 1:1임을 알 수 있었으며, 안정도상수는 치환기효과에 의하여 B15C5-3,4-(NO2)2 < B15C5-NO2 < B15C5-CHO < B15C5-Br < B15C5 < B15C5-CH3 순으로 증가함을 알 수 있었다. 또한 용매변화에 따른 안정도 상수의 순위는 용매 염기도(DN)에 역비례하는데 이는 용매의 염기도, 리간드의 염기도, 금속이온의 용매화 현상 및 착물형성에 따른 엔트로피변화 등으로 설명할 수 있었다.

The chemical compositions and stability constants, thermodynamic parameters for the neodymium(Ⅲ) complexes of substituted benzo-1,4,7,10,13-pentaoxacyclopentadecane(B15C5) have been determined by spectrophotometry and conductometry in methanol solution at various temperatures. As substituents, CH3, Br, CHO, NO2, and 3,4-(NO2)2 were used. In methanol solution the ratios of neodymium(Ⅲ) to the ligands in the complexes are 1 : 1. The stability constants were increased in order of B15C5-3,4-(NO2)2 < B15C5-NO2 < B15C5-CHO < B15C5-Br < B15C5 < B15C5-CH3. This observation can be explained in terms of the substituent effect. The order of stability constants was dimethylsulfoxide < acetone < acetonitrile in solution and the magnitudes were found to be inversely proportional to the solvents donicities. These results could be understood in terms of solvent basicity, ligand basicity, solvation of the cation, and entropy changes of complex formation.

Page
440 - 445
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