Three Co complexes based on 1-(imidazol-1-yl)-4-(imidazol-4-yl)benzene: Syntheses, structures and stability property

Three cobalt(II) complexes with the formulas: {H[CoL3]·4.17MeOH·13.3H2O}n (1), {[Co(HL)3(H2O)2](ClO4)2·2H2O}n (2), and {[Co(HL)2(H2O)2]Cl2}n (3), were obtained by self-assembly of the cobalt(II) salt with HL (HL = 1-(imidazol-1-yl)-4-(imidazol-4-yl)benzene) under different conditions. X-ray diffraction analysis reveals that complex 1 is a 2-fold interpenetrated porous crs framework filled with water molecules and methanol molecules, in which the metal atom has distorted octahedral coordination geometry and the ligand was deprotonated. In 2, the HL without deprotonation links two different Co(II) atoms to form an infinite 1D chain. While complex 3 with octahedral Co(II) atom is a 4-fold interpenetrated dia framework with chloride as counteranions and no deprotonation of the ligand occurred under room temperature condition. In addition, the stability properties of the complexes 1–3 were studied.

Graphical abstractA new ligand 1-(imidazol-1-yl)-4-(imidazol-4-yl)benzene was synthesized. Three cobalt complexes were obtained using different preparation methods. Both 1 and 3 have 3D structures by layering diffusion method. While complex 2 has an infinite 1D chain structure under hydrothermal method. The thermal stability property of them are investigated. The absorption property of complex 1 is studied.Figure optionsDownload full-size imageDownload as PowerPoint slide