Synthesis, Characterization, Crystal Structure Determination and Luminescence Study of New Linear Zn(II) Coordination Polymers with 4,7-Phenanthroline Ligand

Two linear coordination polymers containing Zn(II) and 4,7-phenanthroline (4,7-phen) ligand have been synthesized and structurally characterized by single-crystal X-ray diffraction method. Complexes {[Zn(η2-4,7-phen)X2] ° CH3CN}n (X = Br for 1 and X = I for 2) were synthesized from the reaction of one equivalent of ZnBr2(1) and ZnI2(2) in acetonitrile with one equivalent of 4,7-phen ligand in methanol. Crystals of title complexes suitable for X-ray diffraction experiments have been obtained by slow evaporation of the resulted solution at room temperature. Both complexes have linear polymeric structures which extend parallel to the b axis and contain Zn(II) centers coordinated to two bridging 4,7-phen ligands, and two coordinated halogen molecules, showing a distorted tetrahedral geometry around Zn atoms. In addition, π⋯π (in 1), C-H⋯N (in 1 and 2), C-H⋯Br (in 1) and C-H⋯I (in 2) hydrogen bonding interactions play important role on stabilization of the crystal packing. The luminescence properties of the free ligand as well as the complexes 1 and 2 were investigated in solution.