Four one-dimensional Cu(II) coordination polymers with phthalate and tetrahalogenophthalate ligands: three chain motifs and Cl/Br···π(arene) contacts

Four new one-dimensional Cu(II) coordination polymers (CPs) with diethylenetriamine (dien) and different phthalate derivatives were synthesized and structurally characterized. Single-crystal X-ray diffraction analysis reveals that the complexes { [Cu(dien)(HPhA)]PF 6 ⋅H 2 O} n , 1H , { [Cu 2 (dien) 2 (TFPh)(H 2 O)](CF 3 SO 3 ) 2 } n, 2F , { [Cu(dien)(TClPh)]⋅H 2 O} n , 3Cl, { [Cu(dien)(TBrPh)]⋅H 2 O} n , 4Br, (HPhA= monoanionic phthalate, TFPh = tetrafluorophthalate, TClPh= tetrachlorophthalate and TBrPh= tetrabromophthalate), form 1D chains involving three distinct topologies (Types I–III) that arise from different coordination modes of the dicarboxylate ligands. In 1H , monodentate carboxylate bridges generate Type I chains, whereas 2F displays dinuclear units linked by bridging and terminal carboxylates (Type-II). In 3Cl and 4Br , both carboxylate groups of the tetrahalophthalate ligands bridge adjacent Cu(II) centers in an alternating fashion, giving rise to a type-III chain motif. Analysis of the short contacts shows that only the tetrachloro- and tetrabromophthalate derivatives, 3Cl and 4Br, display geometrical parameters consistent with halogen···π(arene) interactions. These Cl/Br···π(arene) contacts contribute to the interchain organization of the heavier tetrahalophthalate derivatives. Offset Cl/Br···π(arene) contacts were observed in 3Cl and 4Br . The electron paramagnetic resonance (EPR) spectra in solution exhibited A iso and g iso values characteristic of square pyramidal Cu(II) centers, consistent with the solid-state structures and confirming that dien reliably enforces this geometry. These results highlight the structural versatility of Cu(II)/dien/phthalate systems and suggest that Cl/Br···π(arene) contacts contribute to the packing of the heavier tetrahalophthalate derivatives.