Metal–organic coordination architectures of 9,10-bis(N-benzimidazolyl)anthracene: syntheses, structures and emission properties

Abstract

In our continuing efforts to investigate functional metal-organic coordination architectures, a benzimidazole-based rigid ligand, 9,10-bis(N-benzimidazolyl)anthracene (L), has been designed and used to react with Cu^I, Ag^I, Cd^II, Mn^II salts, giving rise to five new metal-organic coordination architectures, [CuLI]₂·2CHCl₃·H₂O (1), [CdL₂(NO₃)₂]·4C₂H₅OH (2), [AgL(BF₄)]·3CHCl₃ (3), [AgL(NO₃)]·2CHCl₃ (4) and [MnL₂Cl₂]·2CHCl₃ (5), which were characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. In 1, the Cu^I ion takes tetrahedral coordination geometry, and the rigid ligands bridge two dinuclear [Cu₂I₂] units to form a two-dimensional (2-D) layer. 2 and 5 show 2-D network structure with (4,4) topology in which the metal ions have octahedral coordination geometry. 3 and 4 display one-dimensional (1-D) chain structures, but show different crystal packing modes due to the effect of anions. These results indicate that the nature of ligand, metal coordination geometry and counter-anions have important effects on the structural topologies of such complexes. Furthermore, complexes 1–4 display strong blue emissions in solid state at room temperature.