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合成了一例以取代苯甲酸衍生物为辅助配体的叠氮铜化合物[Cu(4-Fb)(N3)(H2O)]n(1)(4-Fb=4-formylbenzoate),并对其结构和磁性进行了表征。单晶结构研究表明,化合物1中的最小不对称单元包含一个晶体学独立的Cu(Ⅱ)离子,中心离子呈现了扭曲的四棱锥几何构型。相邻的Cu(Ⅱ)离子之间通过交替的μ-1,1-(EO)-叠氮和syn,syn-羧酸双重桥连接成一维线性金属链。磁性研究揭示,双重桥的超交换反补偿效应导致目标化合物中链内相邻的Cu(Ⅱ)离子之间表现出强的铁磁耦合作用(J=72.1 cm-1)。但是并没有观察到铁磁有序和慢磁弛豫现象。作为影响磁性能的重要结构参数,化合物中Cu-N-Cu的角度(113.34°)与已报道的含双重桥的叠氮铜体系相符。对化合物的磁构关系进行了讨论和探究。此外,密度泛函理论(DFT)计算结果为化合物中相邻Cu(Ⅱ)离子间的铁磁耦合作用提供了定性的理论解释。
An example of azide copper compound [Cu (4-Fb) (N3) (H2O)] n (1) (4-Fb = 4-formylbenzoate) with substituted benzoic acid derivatives as the ancillary ligand was synthesized and its structure And magnetic properties were characterized. The study of single crystal structure shows that the smallest asymmetric unit in compound 1 contains a crystallographic independent Cu (II) ion, and the central ion exhibits a distorted quadrangular pyramid geometry. The adjacent Cu (Ⅱ) ions are connected into a one-dimensional linear metal chain through the alternating μ-1,1- (EO) -azide and the syn, syn-carboxylic acid double bridge. Magnetic studies revealed that the double bridge inverse supercompensation results in a strong ferromagnetic coupling (J = 72.1 cm-1) between adjacent Cu (II) ions in the target compound. However, no phenomena of ferromagnetic order and slow magnetic relaxation have been observed. As an important structural parameter affecting the magnetic properties, the angle of Cu-N-Cu in the compound (113.34 °) is in agreement with reported bis-bridged azide copper systems. The magnetic relationship between the compounds was discussed and explored. In addition, the results of density functional theory (DFT) provide a qualitative and theoretical explanation for the ferromagnetic coupling between adjacent Cu (II) ions in the compound.