Syntheses, structures and magnetic properties of mononuclear, dinuclear and tetranuclear dysprosium(iii) complexes based on azotetrazole-3-hydroxy-2-naphthoic acid

A new compound of azotetrazole-3-hydroxy-2-naphthoic acid (H(3)ATNA) has been successfully synthesized and characterized. By controlling the ratio of metal ions to the ligand and the pH value of solution, mononuclear, dinuclear and tetranuclear dysprosium(iii) complexes [Et3NH](3)[Dy(HATNA)(3)].5H(2)O (1), [Dy-2(HATNA)(3)(DMF)(H2O)].2DMF.CH3OH.2H(2)O (2) and [Et3NH](6)[Dy-4(ATNA)(6)(H2O)(2)].DMF.2CH(3)CN.8H(2)O (3) were synthesized and characterized by X-ray diffraction crystallography (DMF = N,N-dimethylformamide). Crystallographic data demonstrate that the neutral H(3)ATNA exists as a hydrazone tautomer. Complex 1 is a mononuclear structure, in which the Dy(iii) ion is a nine-coordinated ion surrounded by three tridentate HATNA(-) ligands. Complex 2 shows a dinuclear structure, which is bridged by three mu(1,1)-hydroxyl groups of three HATNA(-) ligands. In complex 2, the Dy(iii)1 ion is a nine-coordinated ion surrounded by three tridentate HATNA(-) ligands, while Dy(iii)2 is an eight coordinated atom with three tridentate HATNA(-) ligands, one DMF and one water molecule. Complex 3 displays a tetranuclear structure, which can be approximately considered as two mu(1,3)-carboxyl groups of ATNA(3-) ligands linking complex 2. The magnetic properties of 1-3 were investigated. Complexes 2 and 3 display slow magnetic relaxation in a zero dc field.

Automated summary

A new compound of azotetrazole-3-hydroxy-2-naphthoic acid (H(3)ATNA) has been synthesized and characterized, and dysprosium(iii) complexes with different nuclearity have been successfully synthesized. The crystal structures and magnetic properties of these complexes have been investigated.