Department of Chemistry, University College of Science, University of Calcutta, 92, A.P.C. Road, Kolkata, 700 009, India.
Dalton Trans. 2010 Aug 28;39(32):7474-84. doi: 10.1039/c0dt00331j. Epub 2010 Jul 12.
Three novel mixed bridged trinuclear and one tetranuclear copper(II) complexes of tridentate NNO donor Schiff base ligands [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(CH(3)OH)(2)(BF(4))(2)] (1), [Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (2), [Cu(3)(L(2))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)] (3) and [Cu(4)(L(3))(2)(mu(1,1)-N(3))(4)(mu-CH(3)COO-1kappaO:2kappaO')(2)] (4) have been synthesized by reaction of the respective tridentate ligands (L(1) = 2-[1-(2-dimethylamino-ethylimino)-ethyl]-phenol, L(2) = 2-[1-(2-diethylamino-ethylimino)-ethyl]-phenol, L(3) = 2-[1-(2-dimethylamino-ethylimino)-methyl]-phenol) with the corresponding copper(ii) salts in the presence of NaN(3). The complexes are characterized by single-crystal X-ray diffraction analyses and variable-temperature magnetic measurements. Complex 1 is composed of two terminal [Cu(L(1))(mu(1,1)-N(3))] units connected by a central [Cu(BF(4))(2)] unit through nitrogen atoms of end-on azido ligands and a phenoxo oxygen atom of the tridentate ligand. The structures of 2 and 3 are very similar; the only difference is that the central unit is [Cu(NO(3))(2)] and the nitrate group forms an additional mu-NO(3)-1kappaO:2kappaO' bridge between the terminal and central copper atoms. In complex 4, the central unit is a di-mu(1,1)-N(3) bridged dicopper entity, [Cu(2)(mu(1,1)-N(3))(2)(CH(3)COO)(2)] that connects two terminal [Cu(L(3))(mu(1,1)-N(3))] units through end-on azido, phenoxo oxygen and mu-CH(3)COO-1kappaO:2kappaO' triple bridges to result in a tetranuclear unit. Analyses of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the copper(II) ions in complexes 1-3, with the exchange parameter J of -9.86, -11.6 and -19.98 cm(-1) for 1-3, respectively. In complex 4 theoretical calculations show the presence of an antiferromagnetic coupling in the triple bridging ligands (acetato, phenoxo and azido) while the interaction through the double end-on azido bridging ligand is strongly ferromagnetic.
三种新型混合桥联三核和一种四核铜（II）配合物，由三齿 NNO 供体希夫碱配体[Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(CH(3)OH)(2)(BF(4))(2)]（1）、[Cu(3)(L(1))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)]（2）、[Cu(3)(L(2))(2)(mu(1,1)-N(3))(2)(mu-NO(3)-1kappaO:2kappaO')(2)]（3）和[Cu(4)(L(3))(2)(mu(1,1)-N(3))(4)(mu-CH(3)COO-1kappaO:2kappaO')(2)]（4）通过相应三齿配体（L(1) = 2-[1-(2-二甲基氨基-乙基亚氨基)-乙基]-苯酚，L(2) = 2-[1-(2-二乙氨基-乙基亚氨基)-乙基]-苯酚，L(3) = 2-[1-(2-二甲基氨基-乙基亚氨基)-甲基]-苯酚）与相应的铜（II）盐在 NaN(3)存在下反应合成。这些配合物通过单晶 X 射线衍射分析和变温磁测量进行了表征。配合物 1 由两个末端[Cu(L(1))(mu(1,1)-N(3))]单元组成，通过端接叠氮配体的氮原子和三齿配体的苯氧基氧原子连接一个中心[Cu(BF(4))(2)]单元。2 和 3 的结构非常相似；唯一的区别是中心单元是[Cu(NO(3))(2)]，并且硝酸盐基团在末端和中心铜原子之间形成额外的 mu-NO(3)-1kappaO:2kappaO'桥。在配合物 4 中，中心单元是一个双 mu(1,1)-N(3)桥联双核实体[Cu(2)(mu(1,1)-N(3))(2)(CH(3)COO)(2)]，它通过端接叠氮、苯氧基氧和 mu-CH(3)COO-1kappaO:2kappaO'三重桥连接两个末端[Cu(L(3))(mu(1,1)-N(3))]单元，形成四核单元。变温磁化率数据分析表明，配合物 1-3 中铜（II）离子之间存在全局弱反铁磁相互作用，交换参数 J 分别为-9.86、-11.6 和-19.98 cm(-1)。在配合物 4 中，理论计算表明三重桥联配体（乙酸根、苯氧基和叠氮基）中存在反铁磁耦合，而通过双端接叠氮桥联配体的相互作用是强铁磁的。
