系列双核Ln(III)配合物的晶体结构和磁性

合成了分子式为Ln~2(phen)~2L],phen=C~1~2H~8N~2ALn=Nd,L=(CH~3COO)~4(ONO~2)~2,BLn=Sm,L=(C~6H~5COO)~6,CLn=Eu,L=(C~6H~5COO)~6]3种同双核配合物。用X射线四圆衍射仪测定了3种化合物的结构。在化合物A分子中,2个Nd(III)原子由4个CH~3COO^-基团桥联,以phen和ONO~2^-为端基,构成了一个具有C~2对称性的双核分子。配合物B和C具有完全相同的结构,它们是以4个苯甲酸根为桥,2个phen和2个C~6H~5COO^-为端基的中心对称双核分子,其中6个苯甲酸根的成键状态可分为3种状况。在3种化合物中,每个Ln均为9配位,呈不规则多面体。Ln-Ln距离,A为0.397nm,B和C均为0.405nm。测定了各配合物的变温磁化率,通过对磁性质研究,发现化合物A在低温下具有反铁磁物质行为,并由理论拟合,求得了磁参数g,J值。

Crystal structures and magnetism of the binuclear Ln(III) complexes

Three binuclear Ln(III) complexes with formulas Ln~2(phen)~2L], phen=C~1~2H~8N~2, A Ln=Nd, L=(CH~3COO)~4(ONO~2); B Ln=Sm, L= (C~6H~5COO)~6; C Ln=Eu, L=(C~6H~5COO)~6] have been synthesized. Their molecular structures and crystal structures have been determined by X-ray diffraction analysis. In the complex A, two Nd(III) ions are bridged by four CH~3COO^- groups and coordinated to two phen and ONO~2^- groups, giving a binuclear Nd~2(phen)~2(ONO~2)~2(CH~3COO)~4 unit. This molecule possesses C~2 point group symmetry. The structures of the complexes B and C are completely same. They are centrosymmetric binuclear molecules with four benzoate bridges and two phen and two C~6H~5COO^- ligands. Every Ln atom is 9-coordinated in an irregular polyhedron. The distance of Ln-Ln is 0.397nm for complex A and 0.405nm for complexes B and C. Cryomagnetic investigations reveal a weak antiferromagnetic property only for the complex A.