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Two new Co II coordination polymers with multifunctional 5‐amino‐2,4,6‐tribromoisophthalic acid and flexible isomeric bis(imidazole) ligands: preparation, crystal structure and characterization
Author(s) -
Su Chang-Kai,
Zhang Kou-Lin
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618004382
Subject(s) - supramolecular chemistry , hydrogen bond , crystallography , chemistry , denticity , ligand (biochemistry) , imidazole , stereochemistry , crystal structure , stacking , coordination polymer , octahedron , supramolecular assembly , benzene , molecule , organic chemistry , biochemistry , receptor
Two new Co II coordination polymers (CPs), namely, catena ‐poly[[[(5‐amino‐2,4,6‐tribromobenzene‐1,3‐dicarboxylato‐κ O )aquacobalt(II)]‐bis[μ‐1,3‐bis(imidazol‐1‐ylmethyl)benzene‐κ 2 N : N ′]] 4.75‐hydrate], {[Co(C 8 H 2 Br 3 NO 4 )(C 14 H 14 N 4 ) 2 (H 2 O)]·4.75H 2 O} n , (1), and poly[(μ‐5‐amino‐2,4,6‐tribromobenzene‐1,3‐dicarboxylato‐κ 2 O 1 : O 3 )[μ‐1,2‐bis(imidazol‐1‐ylmethyl)benzene‐κ 2 N : N ′]cobalt(II)], [Co(C 8 H 2 Br 3 NO 4 )(C 14 H 14 N 4 )] n , (2), have been synthesized successfully by the assembly of multifunctional 5‐amino‐2,4,6‐tribromoisophthalic acid (H 2 ATBIP) and Co II ions in the presence of the flexible isomeric bis(imidazole) ligands 1,3‐bis(imidazol‐1‐ylmethyl)benzene (mbix) and 1,2‐bis(imidazol‐1‐ylmethyl)benzene (obix). The isomeric mbix and obix ligands have a big influence on the structures of CPs (1) and (2). CP (1) is composed of chains of nanometre‐sized elliptical rings, in which the Co II atom exhibits a distorted octahedral coordination geometry and ATBIP 2− acts as a monodentate ligand. Two adjacent chains are interlinked by π–π stacking interactions and hydrogen bonds, resulting in a supramolecular double chain. Hydrogen‐bonded R 8 6 (16) rings extend adjacent supramolecular double chains into a two‐dimensional supramolecular layer. Halogen bonding and a hydrogen‐bonded R 4 2 (8) ring further link the two‐dimensional supramolecular layers, leading to the formation of a three‐dimensional supramolecular network. The Co II ion in CP (2) is tetracoordinated, exhibiting a distorted tetrahedral configuration. The ATBIP 2− ligand exhibits a bis(monodentate) coordination bridging mode, linking adjacent Co II ions into zigzag chains, which are further bridged by the auxiliary bridging obix ligand, resulting in a two‐dimensional (4,4) topological network. Interlayer hydrogen and halogen–halogen bonding further extend the two‐dimensional layers into a three‐dimensional supramolecular network. A detailed analysis of the solid‐state UV–Vis–NIR diffuse‐reflectance spectra of (1) and (2) indicates that a wide optical band gap exists in both (1) and (2). CP (1) exhibits an irreversible dehydration–rehydration behaviour.