Synthesis, structures, and fluorescent properties of azo anthranilic acid and its Cu(II), Co(II), and Ni(II) complexes

Abstract

Three new complexes, [Cu(II)L]_n (1), [Co(II)L(H₂O)]_n (2), and [Ni(II)L(DMF)(H₂O)₂] (3), where H₂L = [2-(2-(3-methyl-5-oxo-1-phenyl-1H-pyrazol-4(5H)-ylidene) hydrazinyl) benzoic acid], were synthesized and characterized via elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that 1, 2, and 3, formed by H₂L with metal nitrate, have zigzag chain, helical chain, and mononuclear structures, respectively. The luminescence spectra study reveals that 1 has two emission peaks at 470 and 540 nm, which are attributed to intraligand charge transfer and ligand-to-metal charge transfer fluorescent emission, respectively. In 2 and 3, almost 100% fluorescence emission quenching is observed.

Graphical Abstract

Keywords:

• Azo anthranilic
• Coordination polymer
• Crystal structure
• Thermal property
• Fluorescent property

Additional information

Funding

Funding. This work was supported by the National Natural Science Foundation of China (Projects 21061016 and 21371151) and Yunnan Provincial Department of Education Research Fund (Project 2011Y111).