Both magnetic relaxation and luminescence of Zn2Dy2 cluster complexes regulated by the bis-imine chain in Schiff base ligands
Both magnetic relaxation and luminescence of Zn2Dy2 cluster complexes regulated by the bis-imine chain in Schiff base ligands
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希夫碱配体中双亚胺链调控 Zn2Dy2 簇配合物的磁弛豫和发光
DOI：
10.1039/c9nj03659h
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发表时间：
2019
影响因子：
3.3
通讯作者：
Zhu Dao-Ben
中科院分区：
文献类型：
--
作者：
Liu Cai-Ming;Zhang De-Qing;Zhang Yi-Quan;Li Miao;Zhu Dao-Ben
合成了两个由[DyZn 2（salen）2Cl 2]+和[Dy（bpdc）2]−（bpdc 2 − = 2，2 ′-bipyridine-6，6 ′-dicarboxylate）组成的新型Zn 2Dy 2 Schiff碱簇合物.在1500 Oe的直流电场下，两个簇合物都发生了两步磁弛豫，它们的有效能垒可以通过席夫碱中的双亚胺链来调节。配合物1，[Dy 2 Zn 2（La）2（bpdc）2Cl 2）]·3 MeOH [H2 La = N，N′- bis（3-甲氧基亚水杨基）-1，3-二氨基丙烷]，Ueff/k值为20.2（0.3）K和τ0值为6.7（0.2）× 10−8 s（快速弛豫（FR）阶段）以及Ueff/k值243.2（4.9）K和τ0值为6.0（0.3）× 10−10 s（慢弛豫（SR）相）;配合物2 [Dy_2Zn_2（Lb）_2（bpdc）_2Cl_2）]·MeOH·H_2O [H_2Lb = N，N′-bis（3-甲氧基亚水杨基）-1，2-二氨基乙烷]，具有22.0的Ueff/k值FR相的Ueff/k值为205.7（4.4）K，τ0值为4.6（0.1）× 10−8 s; SR相的Ueff/k值为205.7（4.4）K，τ0值为1.7（0.2）× 10−9 s。此外，这两个配合物显示出双重发射中心不仅镧系元素（III）离子，但也在可见光区的配体，其中金属中心的发射是密切相关的salen配体上的双亚胺链的长度。1的平均荧光寿命（τ）（10.6ns）比2的平均荧光寿命（0.86ns）长一个数量级。
Two novel Zn2Dy2 Schiff base cluster complexes composed of [DyZn2(salen)2Cl2]+ and [Dy(bpdc)2]− complex-fragment building blocks (bpdc2− = 2,2′-bipyridine-6,6′-dicarboxylate) have been prepared, which exhibit interesting T-shaped metal cores and ferromagnetic interactions. Two-step magnetic relaxation was observed under a 1500 Oe dc field for both cluster complexes, and their effective energy barrier can be regulated by the bis-imine chain in the Schiff base. Complex 1, [Dy2Zn2(La)2(bpdc)2Cl2)]·3MeOH [H2La = N,N′- bis(3-methoxysalicylidene)-1,3-diaminopropane], has the Ueff/k value of 20.2(0.3) K and the τ0 value of 6.7(0.2) × 10−8 s for the fast relaxation (FR) phase as well as the Ueff/k value of 243.2(4.9) K and the τ0 value of 6.0(0.3) × 10−10 s for the slow relaxation (SR) phase; while complex 2, [Dy2Zn2(Lb)2(bpdc)2Cl2)]·MeOH·H2O [H2Lb = N,N′-bis(3-methoxysalicylidene)-1,2-diaminoethane], possesses the Ueff/k value of 22.0(0.4) K and the τ0 value of 4.6(0.1) × 10−8 s for the FR phase as well as the Ueff/k value of 205.7(4.4) K and the τ0 value of 1.7(0.2) × 10−9 s for the SR phase. Furthermore, the two complexes exhibit dual emission centered on not only the lanthanide(III) ion but also the ligand in the visible region, of which the metal-centered emission is closely related to the length of the bis-imine chain on the salen ligand. The average fluorescence lifetime (τ) of 1 (10.6 ns) is an order of magnitude longer than that of 2 (0.86 ns).