Diogo Emilay B T, da Silva Júnior Eufrânio N, Oliveira Willian X C, Stumpf Humberto O, Fabris Fernando, de Almeida Adriele A, Knobel Marcelo, Ferreira Fabio F, Nunes Wallace C, Pedroso Emerson F, Julve Miguel, Pereira Cynthia L M
Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Pampulha, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Rua Sérgio Buarque de Holanda, 777, Cidade Universitária Zeferino Vaz, Barão Geraldo, Campinas, SP, 13083-859, Brazil.
Chem Asian J. 2024 Dec 16;19(24):e202400887. doi: 10.1002/asia.202400887. Epub 2024 Oct 31.
The search for new metal-organic compounds as candidates for quantum information processing technologies is in the spotlight. Several metal ions and organic linkers have been used to obtain such compounds. Herein, we describe the synthesis, crystal structures, and cryomagnetic properties of two air-stable isostructural neodymium(III) and europium(III) one-dimensional (1D) coordination polymers of formula [Nd(Hmpa)(DMSO)] (1) and [Eu(Hmpa)(DMSO)] (2) [Hmpa=N-(4-methylphenyl)oxamate, and DMSO=dimethylsulfoxide]. These complexes were prepared by reacting n-BuN(Hmpa) proligand [n-BuN=tetra-n-butylammonium] and the correspondent LnCl ⋅ 6HO salt (Ln=Nd or Eu) in the open air and mild conditions. The crystal structures of 1 and 2 reveal the Ln ion surrounded by two DMSO molecules and three oxamate ligands, one of them connecting to adjacent mononuclear entities through carboxylate bridges featuring a homometallic chain, while the other two establishing double N-H ⋅ ⋅ ⋅ O hydrogen bonds among adjacent polymers to give a resultant supramolecular 2D network. Cryomagnetic measurements in the static (dc) and dynamic current (ac) regimes reveal that 1 behaves as a field-induced single-molecule magnet below 8.8 K. A photoluminescence study shows that Hmpa ligands efficiently sensitize the luminescence of Eu complex in the visible region in the solid state at room temperature.
寻找新型金属有机化合物作为量子信息处理技术的候选材料备受关注。人们已使用多种金属离子和有机连接体来制备此类化合物。在此，我们描述了两种空气稳定的同构钕（III）和铕（III）一维（1D）配位聚合物[Nd(Hmpa)(DMSO)]（1）和[Eu(Hmpa)(DMSO)]（2）[Hmpa = N-(4-甲基苯基)草氨酸酯，DMSO = 二甲基亚砜]的合成、晶体结构和低温磁性性质。这些配合物是通过在空气中温和条件下使前体配体n-BuN(Hmpa)[n-BuN = 四正丁基铵]与相应的LnCl₃·6H₂O盐（Ln = Nd或Eu）反应制备的。1和2的晶体结构显示，Ln离子被两个DMSO分子和三个草氨酸酯配体包围，其中一个通过具有同金属链的羧酸盐桥连接相邻的单核实体，而另外两个在相邻聚合物之间形成双N-H····O氢键，形成超分子二维网络。静态（dc）和动态电流（ac）模式下的低温磁性测量表明，1在8.8 K以下表现为场诱导单分子磁体。光致发光研究表明，在室温下，Hmpa配体在固态中能有效敏化Eu配合物在可见光区域的发光。
