Three new copperâazido complexes [Cu4(N3)8(L1)2]n (1), [Cu4(N3)6(L2)2(H2O)2] (2), and [Cu4(N3)6(L3)2]n (3) [L1 is the imine resulting from the condensation of pyridine-2-carboxaldehyde with N-methylethylenediamine, HL2 and HL3 are the condensation products of 2-hydroxy-3-methoxybenzaldehyde with N,N-diethylethylenediamine and N-ethylethylenediamine respectively] have been synthesized by using 0.5 molar equivalents of the Schiff base ligands with Cu(NO3)2·3H2O and an excess of NaN3. Single crystal X-ray structures show that the basic unit of these complexes contains very similar CuII4 building blocks. While 1 and 3 have overall 1D structures, 2 forms discrete tetranuclear clusters due to blocking of two coordination sites on the tetranuclear cluster by water molecules. Magnetic susceptibility measurements over a wide range of temperatures exhibit the presence of both antiferromagnetic and ferromagnetic exchanges within the tetranuclear unit structures. Density functional theory calculations (using B3LYP functional and two different basis sets) have been performed on the complexes 1â3 to provide a qualitative theoretical interpretation of their overall magnetic behavior.
三种新的
叠氮铜配合物[Cu4(N3)8(L1)2]n (1)、[Cu4(N3)6(
L2)2(
H2O)2](2)和[Cu4(N3)6(L3)2]n (3) [L1 是
吡啶-2-甲醛与
N-甲基乙二胺缩合生成的
亚胺、H
L2 和 HL3 分别是 2-羟基-
3-甲氧基苯甲醛与
N,N-二乙基乙二胺和
N-乙基乙二胺的缩合产物]是用 0.5摩尔当量的希夫碱
配体与Cu(
NO3)2Â-3 和过量的NaN3合成的。单晶 X 射线结构显示,这些复合物的基本单元包含非常相似的 CuII4 结构单元。1 和 3 具有整体一维结构,而 2 则由于
水分子阻挡了四核簇上的两个配位位点而形成了不连续的四核簇。大范围温度下的磁感应强度测量结果表明,四核单元结构中存在反
铁磁和
铁磁交换。我们对复合物 1â3 进行了密度泛函理论计算(使用 B3LYP 函数和两个不同的基集),以便对其整体磁性行为进行定性理论解释。