Syntheses,Crystal Structures and Electrochemical Properties of Supramolecular Complexes [M4L12]·（HPO4）·（PO4）2（L=2,2＇-Dibenzimidazole,M=Co and Ni）

Two novel supramolecular complexes,M4L12]·(HPO4)·(PO4)2(L = 2,2'-dibenzi-midazole,M = Co and Ni) were synthesized by the hydrothermal method and characterized by elemental analysis,IR,UV,and TG-TGA,and the crystal structures were determined by single-crystal X-ray diffraction.The results showed that both of them belong to the cubic system and space group I 4 3d.Crystal parameters of C168H121Co4N48O12P3(1):a = b = c = 2.5104(6) nm,V = 15.820(7) nm3,Mr = 3332.75,Z = 4,Dc = 1.399 Mg/m3,μ = 0.521 mm-1,F(000) = 6852,S = 1.011,the final R = 0.0248 and wR = 0.0663 for 2120 observed reflections(I > 2σ(I)) and R = 0.0315 and wR = 0.0706 for all data.Crystal parameters of C168H121Ni4N48O12P3(2):a = b = c = 2.4977(5) nm,V = 15.581(5) nm3,Mr = 3331.87,Z = 4,Dc = 1.420 Mg/m3,μ = 0.587 mm-1,F(000) = 6868,S = 1.074,the final R = 0.0443 and wR = 0.1364 for 1774 observer reflections(I > 2σ(I)) and R = 0.0647 and wR = 0.1492 for all data.Each of them consisted of four M(II) cations,twelve 2,2'-dibenzimidazole ligands,one monohydrogen phosphate anion and two phosphate anions in the single cell.The central M(II) cation,coordinated with six alkaline nitrogen atoms from three 2,2'-dibenzimidazole ligands,displayed the expected distorted-octahedral geometry.The 3D supramolecular system was formed by the hydrogen bond N-H...O and π-π stacking interaction between neighboring single cells.Complex 1 showed two irreversible single-electron reduction processes of the central metal ion at-0.06 and-0.42 V in DMF solution.