Heteronuclear and homonuclear Ni(II) complexes constructed based on 8-hydroxyquinoline-2-carbaldehyde oxime: Structure and its behavior in solution

Abstract

The organic ligand (E)-8-hydroxyquinoline-2-carbaldehyde oxime (H2L) was used to react with Ni(CH3COO)2·4H2O and NaN(CN)2 at 100 °C to obtain the complex [Ni3Na(HL)3(L)2]n·4nCH3CN (1). Interestingly, the five ligands in the structure chelate three Ni ions, and the uncoordinated O on the ligand captures one Na+. However, the above scheme remains the same, and after adding isonicotinic acid (ina), it obtained the complex [Ni4(HL)4(L)2]2·2CH3CN (2), which eight Ni2+ ions are coordinated by twelve ligands. The component distribution of the complexes in different solutions was measured by electrospray-ionization mass spectrometry (ESI-MS). It was found that the complexes exhibited different component distribution in different solutions. Not only the existence of low-nuclear molecular ion peaks could be monitored, but even higher-nuclear components could also be detected, and the alkali metal ions could be effectively identified. It was indicating that the compounds would assemble differently in different solutions. Surprisingly, homonuclear clusters 2 was providing a basis for further directing the directed synthesis of higher nuclear clusters.