Two Coordination Polymers Based on the Flexible N-Substituted 2,2'-Biimidazole Ligand: Solvothermal Synthesis, Crystal Structures and Characterizations

摘要

Two new supramolecular complexes,[Cu2(Pra2biim)2(H2O)2]·2H2O (1) and [Mn(Pra2biim)(H2O)2]n (2) (H2Pra2biim =1,1'-di(propionic acid)-2,2'-biimidazole) have been prepared and structurally characterized by thermogravimetric analysis,elemental analysis,IR spectra and single-crystal X-ray diffraction.Single-crystal X-ray diffraction analysis reveals that complex 1 crystallizes in the triclinic,space group Pi with a =8.403,b =9.60970(10),c =10.5681(2) (A),V=736.272(16) (A)3,Z=1,Dc =1.695 g/cm3,F(000) =386,GOOF=1.156,R(I＞ 2σ(I)) =0.0396 and wR (I ＞ 2σ(I)) =0.1060,and exhibits a dinuclear structure formed by the connection of Cu2+ ions with two bridging Pra2biim2-ligands.Complex 2 crystallizes in the monoclinic,space group Pc with a =9.058(4),b =5.2745(16),c =17.591(7) (A),V=733.2(5) (A)3,Z =2,Dc =1.663 g/cm3,F(000) =378,GOOF =1.060,R(I ＞ 2σ(I)) =0.0885 and wR(I ＞ 2σ(I)) =0.2199,and the Pra2biim2-ligands link Mn2+ ions to a 63 2D sheet structure.The Pra2biim2-ligand shows two different types of coordination modes.Moreover,hydrogen bonds further stabilize the 3D supramolecular architecture.The magnetic behavior in the temperature range (2～300 K) reveals weaker antiferromagnetic interactions between the Cu2+ ions in 1.