链型四核配合物中的磁交换作用  

Magnetic Exchange Interaction in Linear Tetranuclear Complexes

作　　者：曾成[1] 臧焰[1] 王国雄[1] 戴安邦[1] 

机构地区：[1]南京大学配位化学研究所

出　　处：《化学学报》1990年第7期678-685,共8页Acta Chimica Sinica

基　　金：国家自然科学基金

摘　　要：本文用不可约张量法导出了链型BAAB四核体系的自旋Hamilton算符的矩阵元的一般表达式,用此式系统处理了M·Cu·Cu·M(其中M是氧化数为2的Zn,Cu,Ni,Co,Fe,Mn)即S_2=S_=1/2,S_1=S_4=0,1/2,1,3/2,2,5/2的六个体系,分别得出它们的能级和磁化率公式,我们又合成了七个链型BAAB四核配合物(CuLMX_4)_2,其中L为双(N-氧化吡啶-2-甲醛)缩乙二胺(L′)或双(N-氧化吡啶-2-甲醛)缩-1,2-丙二胺(L″).用CF-1型提拉样品磁强计测定了它们在4.2-300K范围内的变温磁化率,然后用理论得出的公式对实验数据进行最小二乘法拟合,得出磁交换常数J值和J′值以及分裂因子g值,所得J值说明了本文中的七个(CuLMX_4)_2型分子中,中间两个Cu原子之间有弱的铁磁性交换作用,而所得的J′值则表明链端的M与相邻的Cu之间有弱的反铁磁性相互作用,最后用AGK理论对交换途径作了说明。Using irreducible tensor method, we have derived the general expression of the matrix element of the hamiltonian H of linear tetranuclear BAAB complex. The systems of M·Cu·Cu·M (M is Ni, Co, Fe or Mn with oxidation number 2), that is, S_2=S_3=1/2, S_1=S_4=1, 3/2, 2 or 5/2 have been systematically treated with the general expression to obtain their energy levels and magnetic susceptibility formulas. Seven linear tetranuclear BAAB complexes (CuLMX_4)_2 with L=2, 2'-[1, 2-ethanediylbis (nitrilomethylidyne)] bis-pyridine N-oxide (L')or 2, 2'-[1, 2-propanediylbis(nitrilomethylidyne)] bis-pyridine N-oxide(L'), X=Cl or Br, have been synthesised and their temperature dependences of magnetic susceptibilities have been determined within temperature range 4.2—300K by CF-1 extracting sample magnetometer. The experimental magnetic susceptibility data have been fitted with the theoretical formulas, and the magnetic exchange constants J and J' and splitting factor g values have been obtained. Small positive J values show that there is weak ferromagnetic interaction between two central Cu atoms and small negative J' values show that there is weak antiforromagetic interaction between M and its vicinal Cu. The exchange pathway has been explained with the AGK (Anderson-Goodenough-Kanarnori) theory.

关 键 词：四核 链型 配合物 磁交换 

分 类 号：O641.4[理学—物理化学]