丁二酸鹽與乙醯丙酮配位基之雙核錳錯化合物的合成、
結晶構造及磁性研究
洪 當 明* 林俊平**
*慈濟技術學院護理系
摘 要
本文敘述丁二酸鹽與乙醯丙酮配位基之雙核錳錯化合物[Mn2III,III (suc)(acac)4] (suc=丁二酸鹽, acac=乙醯丙酮) 的合成、結晶構造及其磁性。從X_光繞射光譜分析結果，得知其為雙核之錯化合物，兩個錳原子與丁二酸鹽氫氧基之氧原子，以架橋式互相連接，另外再與四個乙醯丙酮 (每個錳原子各兩個) 配位基，以蟹形互相連接，形成八面體之分子結構，兩個錳原子之間隔為3.3558 A。在磁性方面，得知此雙核錯化合物磁性與溫度的關係，從300 K時的莫耳磁化率為4.12 cm3 K mol? 遞減至2 K時的莫耳磁化率為0.04 cm3 K mol?，顯示此雙核之錯化合物有分子內之反磁性自旋交換產生，配位場自旋藕合常數值(J )為J=_2.18 cm?。
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Synthesis,Crystal Structure and Magnetic Properties of New Binuclear Manganese(III,III) Complex of Succinate and 2,4-pentanedione Ligand
Dang-Ming Hong＊ Jiun-Ping Lin＊＊
洪 當 明 林 俊 平
＊Professor, Dept. of Nursing, Tzu-Chi College of Technology
慈濟技術學院護理系教授
＊＊Lecturer, Dept. of Mechanical Eng., Dahan Institute of Technology
大漢技術學院機械工程系講師
Abstract
The crystal structure and magnetic properties are reported for binuclear manganese complex [Mn2III,III (suc)(acac)4] (suc=succinate, acac=2,4-pentanedionate). The X-ray crystal structure of complex is a binuclear complex, where the two manganese atoms are bridged by two hydroxyl oxygen of succinate and acac bridging ligands with a MnMn separation of 3.3558A. Cryomagnetic investigations (2~300 K) get the χm T values decrease from 4.12 cm3 K mol? at 300 K to 0.04 cm3 K mol? at 2 K, which reveal an intramolecular antiferromagnetic spin exchange and the field splitting with J=_2.18 cm?.
Keywords: Crystal structure; Magnetic properties; Binuclear complex; Ligand
Introduction
The manganese complexes play indispensable roles in biological system involving the photosynthesis of green plants1,2 and the manganese redox reaction in catalase1,3,4. Recently, A number of manganese complexes, non-heme enzymes have been isolated and characterized3,4. There has been point out the structure of the catalase-like manganese complexes, which have 2.7~3.5 A of MnMn distances5,6. Therefore, the intermetallic separation and the arrangement of the ligands are essential in designing of redox manganese complexes.
The carboxylate ion may coordinate to transition metal in unidentate or bidentate, more interest of succinate having two carboxylate ions. Binuclear manganese complexes bridged by succinate are interest particularly. In our laboratory, we prepared a new dinuclear manganese(III,III) complex [Mn2III,III (suc)(acac)4] . In this paper, I report the investigations of synthesis, X-ray crystal structure and magnetic properties about the complex.