Positional isomeric effect on CuII and CdII complexes based on perfluorinated dicarboxylate ligands and bipyridyl co-tectons

Five novel CuII and CdII complexes with the formula {[Cu2(HBDO-F4)2(BDO-F4)-(2,2′-bipy)2](CH3OH)} (1), [Cd2(BDO-F4)2(2,2′-bipy)2(H2O)2] (2), {[Cu(BDO-F4)(4,4′-bipy)(H2O)2](CH3OH)2}n (3), {[Cd(BDO-F4)(4,4′-bipy)(H2O)2](CH3OH)2}n (4) and {[Cd(BDC-F4)-(2,2′-bipy)](H2O)2}n (5) have been prepared by reaction of metal perchlorates with H2BDO-F4 (tetrafluorophthalic acid) or H2BDC-F4 (tetrafluoroterephthalic acid) in the presence of different bipyridyl co-ligands (2,2′-bipy = 2,2′-bipyridine and 4,4′-bipy = 4,4′-bipyridine). All these complexes were characterized by elemental analysis, IR spectra and X-ray single crystal diffraction. Complexes 1 and 2 show binuclear structures, and further connected by hydrogen bonding to result in the final supramolecular 3-D framework and 1-D box-like chain, respectively. Polymers 3 and 4 are isostructural, where the metal centers are connected by BDO-F42− and 4,4′-bipy ligands to generate a 2-D grid-like (4,4) network. These layers are interlinked through hydrogen bonds to form a 3-D architecture. Complex 5 exhibits a distinct (4,4) coordination layer constructed by paddle-wheel [Cd2(COO)4] dinuclear subunits. The results reveal that the diverse structure of 1–5 can be adapted by the different positions of carboxylate groups of perfluorinated ligands, as well as the metal centers and auxiliary ligands. Moreover, their thermal stability and fluorescent properties have also been investigated.

Graphical abstractA series of CuII/CdII complexes containing perfluorinated benzenedicarboxylate derivatives and bipyridyl co-ligands were synthesized and profoundly regulated by the positional effect of carboxylate groups from substituted benzenedicarboxylates and N-donor of auxiliary ligands. Their thermal stability and fluorescence properties were not stimulated by positional effects of the diversified ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide