Yadav Munendra, Mereacre Valeriu, Lebedkin Sergei, Kappes Manfred M, Powell Annie K, Roesky Peter W
Institut für Anorganische Chemie, Karlsruher Institut für Technologie , Engesserstrasse 15, 76131 Karlsruhe, Germany.
Inorg Chem. 2015 Feb 2;54(3):773-81. doi: 10.1021/ic5014957. Epub 2014 Sep 19.
The Schiff-base (2-aminoethyl)hydroxybenzoic acid (H(2)L) as a proligand was prepared in situ from 3-formylsalicylic acid and ethanolamine (ETA). The mononuclear {[Y(HL)(4)][ETAH]·H(2)O} (1) and {[Dy(HL)(4)] [ETAH]·3MeOH·H(2)O} (2) and tetranuclear {[Y(4)(HL)(2)(L)(4)(μ(3)-OH)(2)]·4MeOH·4H(2)O} (3), {[Dy4(HL)(2)(L)(4)(μ(3)-OH)(2)]·5(MeOH)(2)·7H(2)O (4), and {[Dy(4)(HL)(8)(L)(2)]·4MeOH·(2)H(2)O}(5) rare-earth metal complexes of this ligand could be obtained as single-crystalline materials by the treatment of H(2)L in the presence of the metal salts [Ln(NO(3))(3)·(H(2)O)m] (Ln = Y, Dy). In the solid state, the tetranuclear compounds 3 and 4 exhibit butterfly structures, whereas 5 adopts a rectangular arrangement. Electrospray ionization mass spectrometry data of the ionic compounds 1 and 2 support single-crystal X-ray analysis. The yttrium compounds 1 and 3 show fluorescence with 11.5% and 13% quantum yield, respectively, whereas the quantum yield of the dysprosium complex 4 is low. Magnetic studies on the dysprosium compounds 4 and 5 suggest the presence of weak antiferromagnetic interactions between neighboring metal centers. Compound 4 shows single-molecule-magnet behavior with two relaxation processes, one with the effective energy barrier U(eff) = 84 K and the preexponential factor τ(0) = 5.1 × 10(-9) s.
席夫碱（2-氨基乙基）羟基苯甲酸（H₂L）作为前体配体，由3-甲酰基水杨酸和乙醇胺（ETA）原位制备。通过在金属盐[Ln(NO₃)₃·(H₂O)ₘ]（Ln = Y，Dy）存在下处理H₂L，可获得该配体的单核{[Y(HL)₄][ETAH]·H₂O}（1）、{[Dy(HL)₄][ETAH]·3MeOH·H₂O}（2）以及四核{[Y₄(HL)₂(L)₄(μ₃-OH)₂]·4MeOH·4H₂O}（3）、{[Dy₄(HL)₂(L)₄(μ₃-OH)₂]·5(MeOH)₂·7H₂O（4）和{[Dy₄(HL)₈(L)₂]·4MeOH·(2)H₂O}(5)稀土金属配合物的单晶材料。在固态下，四核化合物3和4呈现蝴蝶结构，而5则采用矩形排列。离子化合物1和2的电喷雾电离质谱数据支持单晶X射线分析。钇化合物1和3分别以11.5%和13%的量子产率显示荧光，而镝配合物4的量子产率较低。对镝化合物4和5的磁性研究表明相邻金属中心之间存在弱反铁磁相互作用。化合物4表现出具有两个弛豫过程的单分子磁体行为，一个弛豫过程的有效能垒U(eff) = 84 K，预指数因子τ(0) = 5.1×10⁻⁹ s。
