Synthesis, structure, fluorescence, and magnetic studies of a series of transition metal complexes with oxygen-bridged phenylene tricarboxylic acid ligand

Abstract

In this work, 4-(2-carboxyphenoxy)phthalic acid ligand (H3bppa), 4,4′-dipyridyl (4,4′-dipy), 1,10-phenanthroline (phen), 2,2′-dipyridyl (2,2′-dipy) and transition metal ions Zn2+, Cu2+, Mn2+, Ni2+, Co2+ were used to synthesize metal complexes by solvothermal reaction. Ten complexes were synthesized, namely, [Zn(H2bppa)2(H2O)4]·4H2O (1), [Mn(H2bppa)2(H2O)4]·4H2O (2), [Co(H2bppa)2(H2O)4]·4H2O (3), [Mn(H2bppa)2 (2,2′-dipy) (H2O)]n (4), [Cu(H2bppa)2 (2,2′-dipy) (H2O)]n (5), [Mn3(bppa)2(4,4′-dipy)2 (H2O)6]n (6), [Co(Hbppa) (phen)2 (H2O)] (7) and [Ni(Hbppa) (phen)2 (H2O)] (8), [Mn(Hbppa) (phen) (H2O)]n (9), [Cu(Hbppa) (phen) (H2O)]n (10). Structural datas were collected by X-ray single crystal diffractometer, the results show that complexes 1, 2, 3, 7 and 8 are zero-dimensional mononuclear structure, 4, 5, 9 and 10 are one-dimensional chain structure, 6 is three-dimensional network structure. Furthermore, solid state fluorescence properties were performed on complexes H3bppa and 1–8, magnetic properties were performed on complexes 2–8. The fluorescence experiment results show that the fluorescence intensity of complexes 1–8 is weaker than that of H3bppa, and the fluorescence emission spectrum of complex 1 undergoes a blue shift relative to the H3bppa. Magnetic testing data analysis shows that complexes 2, 3 and 8 have antiferromagentic properties and complexes 4, 5, 6 and 7 have ferromagentic properties.