Synthesis, crystal structure and characterization of two new cobalt(II) metal-organic frameworks with 1,4-bis((1h-imidazol-1-yl)methyl) benzene and 1,3,5-tris[(1h-imidazol-1-yl)methyl]benzene ligands

• Published in: Molecular Crystals and Liquid Crystals 2024-04, Vol.768 (6), p.60-72
• Main Authors: Hu, Hong, Chen, Jia-Lu, Yang, Chao-Bo, Zhong, Kai-Long
• Format: Article
• Language: English
• Subjects: Anions; Benzene; Cations; Cobalt; Cobalt(II); Crystal structure; Crystallography; Hydrocarbons; Hydrogen bonding; Ligands; Metal-organic frameworks; Metals; Structural analysis; Topology
• ISSN: 1542-1406; 1563-5287; 1527-1943
• DOI: 10.1080/15421406.2024.2338309

Two novel Co II metal-organic frameworks {[Co(BIMB) 2 (H 2 O) 2 ](SO 4 )·EG·3 H 2 O} n (I) and {[Co(TIMB) 2 ](SiF 6 )} n (II) were hydrothermally synthesized by corresponding metal salt with organic ligands 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (TIMB) or 1,4-bis((1H-imidazol-1-yl)methyl)benzene (BIMB). Crystal structural analysis reveals that they exhibit varied structures. Compound I contains two crystallographically unique Co II centers, each lying on an inversion center and having a slightly distorted octahedral environment. The BIMB ligands link the Co II cations to generate a three-dimensional porous framework with a 4-connected uninodal (6 5 .8) topology. Compound II exhibits a two-dimensional sheeted metal-organic structure running parallel to the (0 0 1) plane, in which TIMB ligands join Co 2+ centers having a six-coordinated octahedral structure. In the solid state, adjacent sheets are further bridged by guest SiF 6 - anions via C-H...F hydrogen-bonding interactions, giving rise to a three-dimensional supramolecular network structure with a 2-nodal (3-c) 2 (6-c) net. The topological analysis suggests that the point Schläfli symbol of compound II is (4 3 ) 2 (4 6 .6 6 .8 3 ). In addition, their thermal stabilities have also been investigated.