羧酸桥联镍(Ⅱ)四氮杂环配合物的合成、晶体结构与磁性

Synthesis,Structure and Magnetic Property of a Terephthalato-bridged Nickel(Ⅱ) Tetraazamacrocyclic Complex

以对苯二甲酸根为桥联基团合成了一个新的镍(Ⅱ)四氮杂环羧酸桥联配合物[Ni(L)tp]∞(L=5-苯甲基-4,6-二甲基-1,3,7,10-四氮杂环十四烷).X射线单晶衍射结果显示,Ni(Ⅱ)离子呈扭曲的八面体构型.每个对苯二甲酸阴离子tp2-按照反式单齿桥联的模式连接两个Ni(Ⅱ)离子,每个Ni(Ⅱ)离子反式桥连两个tp2-配体,tp2-和Ni(Ⅱ)离子交替排列形成一维链状配位聚合物.磁性研究结果表明,配合物的χmT在低温时略有减小,根据结构分析将其归因于链内tp2-传递的弱反铁磁耦合和八面体Ni(Ⅱ)的零场分裂.

A new terephthalato-bridged nickel（ Ⅱ ） complex with a teraazamacrocyclic ligand, [ Ni（L） tp ]∞（ L = 5-benzyl-4,6-bimethyl-1,3,7,10-tetraaza-cyclotetradecane） was synthesized and characterized. On the basis of the X-ray crystallographic study, each Ni（ Ⅱ ） ion lies in a distorted octahedral environment, and the terephthalato ligand bridges two Ni（ Ⅱ ） ions in a trans fashion. The [ Ni（L） ]^2＋ and the tp^2- groups are alternatively arranged yielding a one-dimensional coordination polymer. Magnetic measurements show that the decrease Of χmT below 25 K gave a Weiss constant of θ = - 0.49 K. This behavior may be due to a very weak intrachain magnetic superexchange through the tp^2- bridge, a weak interchain exchange interaction and the zero-field splitting（ZFS） of octahedral Ni（ Ⅱ ） ions.