Jeong Ah Rim, Park Si Ra, Shin Jong Won, Kim Jihyun, Tokunaga Ryuya, Hayami Shinya, Min Kil Sik
Department of Chemistry, Kyungpook National University, Daegu 41566, Republic of Korea.
Department of Chemistry Education, Kyungpook National University, Daegu 41566, Republic of Korea.
Dalton Trans. 2024 Apr 16;53(15):6809-6817. doi: 10.1039/d3dt04385a.
Three Fe(III)-based coordination complexes Fe(dqmp)·HO (1), Fe(dqmp)·2CHCOCH (2), and Fe(dqmp) (3) were synthesized from Fe(NO)·9HO/Fe(ClO)·xHO, NaBF, and 2,4-dichloro-6-((quinoline-8-ylimino)methyl)phenol (Hdqmp) in methanol/acetone and characterized. The structures of complexes 1-3 were determined single-crystal X-ray crystallography at 100 K and room temperature, and their magnetic properties in the solid and solution forms were investigated. All complexes showed meridional structures with two tridentate dqmp ligands coordinated with Fe(III) cations. In the solid state, complex 1 showed an abrupt and complete spin crossover at 225 K, whereas complexes 2 and 3 exhibited an incomplete spin crossover at 135 and 150 K, respectively. In a dimethylformamide solution, the complexes showed counterion-dependent spin transitions. In contrast to the solid state, in solution, complex 1 did not exhibit complete spin crossover. However, complexes 2 and 3 showed more complete spin transitions in solutions than in the solid state. The relaxation times, and , for 1 and 2 were determined and both increased with temperature from 220 to 380 K. The of 1 was larger than that of 2 at 380 K, and the values were larger than the values.
通过在甲醇/丙酮中，由硝酸铁·九水合物/高氯酸铁·x水合物、四氟硼酸钠和2,4-二氯-6-((喹啉-8-基亚氨基)甲基)苯酚（Hdqmp）合成了三种基于Fe(III)的配位配合物Fe(dqmp)·H₂O (1)、Fe(dqmp)·2CH₃COCH₃ (2) 和 Fe(dqmp) (3)，并对其进行了表征。在100 K和室温下通过单晶X射线晶体学确定了配合物1 - 3的结构，并研究了它们在固态和溶液形式下的磁性。所有配合物均呈现经式结构，两个三齿dqmp配体与Fe(III)阳离子配位。在固态下，配合物1在225 K时表现出突然且完全的自旋交叉，而配合物2和3分别在135 K和150 K时表现出不完全的自旋交叉。在二甲基甲酰胺溶液中，这些配合物表现出与抗衡离子相关的自旋转变。与固态相反，在溶液中，配合物1没有表现出完全的自旋交叉。然而，配合物2和3在溶液中的自旋转变比在固态中更完全。测定了1和2的弛豫时间T₁和T₂，两者在220至380 K范围内均随温度升高而增加。在380 K时，1的T₁大于2的T₁，且T₂值大于T₁值。
