Synthesis, crystal structures, photoluminescence, and catalytic reactivity of novel coordination polymers (0-D, 1-D, 2-D to 3-D) constructed from cis-1,2-cyclohexanedicarboxylic acid and various bipyridyl ligands

Abstract

Six ZnII-(e,a-cis-1,2-chdc) complexes, [Zn2(1,2-chdc) 2(2,2′-bpy)2(H2O)2] ·H2O 1, [{Zn2(1,2-chdc)2(H 2O)2(μ-bpa)}·4H2O]n2, [{Zn2(μ-1,2-chdc)2(μ-4,4′-bpy)} ·3CH3OH]n3, [{Zn2(μ-1,2-chdc) 2(μ-bpe)}·2H2O]n4, [[{Zn 2(μ-1,2-chdc)2}n-(μ-bpp)-{Zn 2(μ-1,2-hdc)2(H2O)2}] ·CH3CN·2H2O]n5, and [{Zn 2(μ-dtp)2(μ-1,2-chdc)}2·4· 5H2O]n6 (1,2-chdc = 1,2-cyclohexanedicarboxylate), with different assistant ligands (2,2′-bipyridine (2,2′-bpy), 1,2-bis(4-pyridyl)ethane (bpa), 1,2-bis(4-pyridyl)ethylene (bpe), 1,3-bis(4-pyridyl)propane (bpp), and, 4,4′-bipyridine (4,4′-bpy) and 4,4′-dithiodipyridine (dtp)) have been synthesized and their structures were determined. Depending on the assistant ligands, the structures and dimensionalities of ZnII-(e,a-cis-1,2-chdc) complexes have been varied. Two carboxylates in e,a-cis-1,2-chdc coordinate to ZnII ions with (11) or (10) connectivity. Photoluminescence study of the compounds 1-6 showed that emission spectra of compounds 1, 2, 4, and 5 were observed at 343 nm for 1, 419 nm for 2, 507 nm for 4, 396 nm for 5, respectively, while no obvious luminescences were displayed for 3 and 6. In addition, it has been found that compound 1 catalyzed the transesterification reaction of phenyl acetate with methanol, with quantitative conversion to methyl acetate, under the neutral conditions, while compounds 2-6 showed very slow conversions. The thermal stabilities of these complexes were also examined. © 2011 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.