氯冉酸阴离子桥联双核铜(II)配合物的合成和磁性

本文合成了五种以氯冉酸二价阴离子为桥联配体的Cu(II)单核(CuLCA].H~2O)和双核(Cu~2L~2CA](ClO~4)~2配合物:Ca(phen)CA].H~2O(1),Cu~2(phen)~2CA](ClO~4)~2(2),Cu(NO~2-phen)CA].H~2O(3),Cu~2(NO~2-phen)~2CA](ClO~4)~2(4)和Cu~2(bpy)~2CA](ClO~4)~2(5)。经元素分析、红外、固体紫外、顺磁共振、磁化率及变温磁化率的测定对上述各配合物进行了表征。配合物1,3可能是通过水分子中的氢键将两个CuLCA]单元联接而缔合的假双聚体。配合物2,4,5则由阳Cu~2L~2CA]^2^+阳离子和弱配位的ClO~4^-阴离子所组成。双核配合物中Cu(II)离子的几何构型可能为畸变的四方锥。所有五种配合物均难溶于水及常见有机溶剂。上述配合物的室温ESR谱呈现ΔM~s=2的从单重态到三重态的半场跃迁。配合物2,5的变温磁化率(4-300K)已测得,利用Heisenberg模型确定交换参数J值为-29.2和-25.7cm^-^1。表明在此类桥联配合物中,两核间存在着反铁磁性交换耦合作用。

Synthesis and magnetic properties of binuclear copper(II) complexes using the dianions of chloranilic acids as bridging ligands

Five new copper(II) complexes containing bidentate terminal ligands and dianions of chloranilic acids (CA) have been synthesized, namely Ca(phen)CA].H~2O(1; phen=o-phenanthroline), Cu~2(phen)~2CA](ClO~4)~2 (2), Cu(NO~2-phen)CA].H~2O(3; NO~2-phen=5-Nitro-o-phenanthroline), Cu~2(NO~2-phen)~2CA](ClO~4)~2(4) and Cu~2(bpy)~2CA](ClO~4)~2(5; bpy=2, 2'-biphridyl). CA acts as bridging ligand in these compounds. All complexes have been characterized by elemental analyses, IR, electronic spectra, ESR, susceptibility and variable-temperature magnetic susceptibility. Complex 1, 3 might be associated in pseudodimeric entities formed by two CuLCA].H~2O moieties connected via hydrogen bonding whereas the structures of 2, 4 and 5 are built up by dimeric Cu~2L~2CA]^2^+ cations and weak coordinated ClO~4^- anions. The copper(II) ion coordination geometry is probably distorted square pyramidal in the binuclear complexes. These complexes are very poorly soluble in water or common organic solvenos. Room-temperature ESR spectra of all the complexes studied show that ΔM~s=2 half-field transitions (Singlet-to-triplet). The variable- temperature magnetic susceptibilities of 2 and 5 have been measured (4- 300K). Based on the Heisenbery model, the exchange parameter, J, was found to be -29.2 and -25.7cm^-^1 for 2 and 5, respectively. An antiferromagnetic exchange interaction was suggested between the metal ions in these complexes.