4′-(2-吡啶基)三联吡啶的镧系(Ⅲ)配合物的晶体结构、荧光性质和磁性

Lanthanidecomplexes derived from 4′‑(2‑pyridyl)‑2,2′∶6′,2″‑terpyridine:Crystal structures,fluorescent and magnetic properties

以4'-(2-吡啶基)-2,2'∶6',2″-三联吡啶(2-pyterpy)为配体,通过溶剂热法合成了5个双核配合物[Ln(2-pyterpy)(NO_(3))_(2)(μ-OCH_(3))]_(2)(Ln-2-pyterpy,Ln=Pr、Sm、Eu、Dy、Er)。单晶X射线衍射分析表明,配合物Pr-2-pyterpy和Sm-2-pyterpy同构,属于单斜晶系,P2_(1)空间群,a=0.95643(19)nm,b=1.9654(4)nm,c=1.1935(2)nm,β=90.41(3)°。配合物Er-2-pyterpy属于单斜晶系,C2/c空间群,a=2.8388(6)nm,b=1.2048(2)nm,c=1.5206(3)nm,β=121.70(3)°。粉末X射线衍射研究表明,配合物Eu-2-pyterpy与Dy-2-pyterpy同构且与文献报道的配合物[Ln(2-pyterpy)(NO_(3))_(2)(μ-OCH_(3))]_(2)(Ln=Tb,Dy)结构相同,属于单斜晶系,P2_(1)/n空间群。镧系收缩效应在调整该系列配合物结构中起到了重要作用。固态配合物Ln-2-pyterpy(Ln=Pr、Sm、Eu、Dy)均发射Ln(Ⅲ)的特征荧光。在300 K,配合物Ln-2-pyterpy(Ln=Pr、Sm、Eu、Dy)的χ_(M)T实验值与2个孤立的Ln(Ⅲ)离子的理论值基本一致。根据2 K时χ_(M)T实验值推断,配合物Sm-2-pyterpy和Eu-2-pyterpy的顺磁离子间分别通过甲氧基桥传递弱的反铁磁和铁磁耦合作用。

Five dinuclear complexes[Ln(2⁃pyterpy)(NO_(3))2(μ⁃OCH_(3))]_(2)(Ln⁃2⁃pyterpy,Ln=Pr,Sm,Eu,Dy,Er)were synthesized by solvothermal method using 4'⁃(2⁃pyridyl)⁃2,2'∶6',2″⁃terpyridine(2⁃pyterpy)as ligand.Single crystal X⁃ray diffraction analysis showed that complexes Pr⁃2⁃pyterpy and Sm⁃2⁃pyterpy are isomorphic and crystallize in monoclinic system,space group P2_(1) with a=0.95643(19)nm,b=1.9654(4)nm,c=1.1935(2)nm,β=90.41(3)°.Com⁃plex Er⁃2⁃pyterpy crystallizes in monoclinic system,space group C2/c with a=2.8388(6)nm,b=1.2048(2)nm,c=1.5206(3)nm,β=121.70(3)°.Powder X⁃ray diffraction results showed that complexes Ln⁃2⁃pyterpy(Ln=Eu,Dy)are isomorphic and have the same structure as the reported complexes[Ln(2⁃pyterpy)(NO_(3))2(μ⁃OCH_(3))]_(2)(Ln=Tb,Dy),crystallizing in monoclinic crystal system,space group P2_(1)/n.The lanthanide contraction effect plays an important role in adjusting the structure of this series of complexes.The solid complexes Ln⁃2⁃pyterpy(Ln=Pr,Sm,Eu,Dy)emitted the characteristic fluorescence of Lnions.At 300 K,theχ_(M)T experimental values of complexes Ln⁃2⁃py⁃terpy(Ln=Pr,Sm,Eu,Dy)were consistent with the theoretical values of two corresponding isolated Lnions.Ac⁃cording to theχ_(M)T experimental value at 2 K,the weak antiferromagnetic and ferromagnetic coupling effects be⁃tween the Lnions of the complexes Sm⁃2⁃pyterpy and Eu⁃2⁃pyterpy are transmitted by methoxy⁃bridge,respec⁃tively.CCDC:2333490,Pr⁃2⁃pyterpy;2333491,Sm⁃2⁃pyterpy;2333483,Er⁃2⁃pyterpy.