Extraction Ability and Selectivity for Lithium Ion of Macrocyclic Trinuclear (Alkylbenzene)ruthenium(II) Complexes Bridged by 2,3-Pyridinediolato Ligands
作者:Shoichi Katsuta、Hajime Nomura、Takuya Egashira、Takahiro Imoto、Yoshihiro Kudo、Yasuyuki Takeda
DOI:10.1246/bcsj.20100282
日期:2011.3.15
A series of macrocyclic trinuclear complexes of (η6-alkylbenzene)ruthenium(II) bridged by 2,3-pyridinediolato ligands were synthesized and their liquid–liquid extraction properties for Li+ and Na+ were investigated at 25 °C. The alkylbenzenes used were p-cymene, 1,2,3-trimethylbenzene, 1,3,5-trimethylbenzene, 1,3,5-triethylbenzene, 1,2,4,5-tetramethylbenzene, and hexamethylbenzene. Most of the trinuclear complexes were stable for 48 h or more in a dichloromethane–water system. The extraction constants (Kex = [ML+A−]o/([M+][A−][L]o); M+: alkali metal ion, L: trinuclear complex, A−: counter anion (picrate), and o: organic phase (dichloromethane)) were determined from analysis of the extraction equilibria. Each trinuclear complex exhibited a larger Kex value for Li+ than for Na+; particularly large separation factor, SF = Kex(Li+)/Kex(Na+), was observed for the complexes of Ru(1,3,5-trimethylbenzene) (SF = 1.7 × 103) and Ru(1,2,4,5-tetramethylbenzene) (SF = 1.6 × 103). The extraction separation of Li+ from seawater could be achieved by using the trinuclear complex of Ru(1,3,5-trimethylbenzene) with the aid of washing the organic phase with water to remove co-extracted Na+.
合成了一系列由2,3-吡啶二醇配体桥接的(η6-烷基苯)钌(II)大环三核配合物,并研究了它们在25℃下对Li+和Na+的液-液萃取性能。使用的烷基苯是对伞花烃、1,2,3-三甲基苯、1,3,5-三甲基苯、1,3,5-三乙基苯、1,2,4,5-四甲基苯和六甲基苯。大多数三核配合物在二氯甲烷-水体系中可以稳定48小时或更长时间。萃取常数 (Kex = [ML+A−]o/([M+][A−][L]o);M+:碱金属离子,L:三核络合物,A−:抗衡阴离子(苦味酸盐),o :通过萃取平衡分析确定有机相(二氯甲烷)。每个三核配合物对于 Li+ 表现出比 Na+ 更大的 Kex 值; Ru(1,3,5-三甲基苯) (SF = 1.7 × 103) 和 Ru(1,2,4,5) 配合物观察到特别大的分离因子 SF = Kex(Li+)/Kex(Na+) -四甲基苯)(SF = 1.6 × 103)。利用Ru(1,3,5-三甲苯)三核配合物并用水洗涤有机相去除共萃取的Na+,可以实现海水中Li+的萃取分离。