Eight coordination compounds assembled from unexplored semi-rigid ether-based unsymmetrical tetracarboxylate and various dipyridyl ligands: structural variation, magnetic and photoluminescence properties

Abstract

By incorporating a semi-rigid ether-based unsymmetrical tetracarboxylic acid [H₄detc = 2,3,3′,4′-diphenyl ether tetracarboxylic acid] with various ancillary dipyridyl ligands [phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine, bpea = 1,2-bis(4-pyridyl)ethane, and bpee = 1,2-bis(4-pyridyl)ethylene], eight new coordination compounds were hydrothermally synthesized. [Mn(H₂detc)(phen)₂]·H₂O (1) and [Cd(H₃detc)₂(bipy)₂·H₂O]·6H₂O (2) are two supramolecular networks built from binuclear and mononuclear structures, respectively. [Cd₂(detc)(phen)₂]·0.5H₂O (3) and [Zn(H₂detc)(bipy)] (4) are two luminescent 1D loop chain structures with [M₂(detc)₂] metallacycle units. [Ni₂(detc)(bpee)₂·5H₂O]·1.5H₂O (5) exhibits a 2D fishbone-like double-layered network. [Co₂(detc)(bpea)₂·H₂O] (6) features a 3D framework containing a 1D [Co₂(μ₂-COO)(μ₂-O_carboxylate)] chain. [Cu₂(detc)(bpee)·2H₂O]·4H₂O (7) possesses a two-fold interpenetration 3D framework with a pcu net topology. [Ni₂(detc)(bpea)₂·3H₂O]·3H₂O (8) displays a three-fold interpenetration 3D framework with a (3,3,4)-connected new topological net. Magnetic susceptibility measurements indicate antiferromagnetic exchange interactions between the Co(II) ions in 6. The photoluminescence spectra of compounds 2, 3 and 4 show the corresponding emission bands of their ancillary dipyridyl ligands.