Zinc(ii) coordination architectures with two bulky anthracene-based carboxylic ligands: crystal structures and luminescent properties

Abstract

To systematically investigate the influence of ligands with a large conjugated π-system on the structures and properties of their complexes, we synthesized seven ZnII complexes with two anthracene-based carboxylic ligands, anthracene-9-carboxylic acid (HL1) and anthracene-9,10-dicarboxylic acid (H2L2), and sometimes incorporating different auxiliary ligands, {[Zn(L1)2(H2O)2](H2O)}∞ (1), [Zn5(μ3-OH)2(L1)8(2,2′-bipy)2] (2), Zn2(L1)4(phen)2(μ-H2O) (3), {[Zn(L1)2(4,4′-bipy)(CH3OH)2]}∞ (4), {[Zn(L2)2](Hdmpy)2(H2O)2}∞ (5), {[Zn2(L2)(2,2′-bipy)4](HL2)2}∞ (6) and {[Zn2(L2)(pypz)2(Hpypz)2]}∞ (7) (2,2′-bipy = 2,2′-bipyridine, phen = 1,10′-phenanthroline, Hpypz = 3-(2-pyridyl)pyrazole, 4,4′-bipy = 4,4′-bipyridine and Hdmpy = protonated 2,6-dimethylpyridine), which were characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. 1 has a one-dimensional (1-D) chain structure, whereas 2 exhibits a new pentanuclear cluster structure because of the introduction of a chelating 2,2′-bipy ligand. 3 and 4 take dinuclear and 1-D structures, respectively, by incorporating the auxiliary ligands phen and 4,4′-bipy. 5 is a three-dimensional (3-D) twofold interpenetrating diamondoid framework showing an open channel. 6 and 7 possess the corresponding chain structures containing Zn2 units as nodes by introducing Hpypz and 4,4′-bipy auxiliary ligands, respectively. These results indicate that the nature of ligands and auxiliary ligands has an important effect on the structural topologies of such complexes. Moreover, the luminescent properties of the corresponding complexes and ligands have been briefly investigated.