Studies on one 2D cadmium(II) coordination polymer and two mononuclear cadmium(II) complexes with trans or cis configuration having 3-bromo, 3,6-dibromo, and 3,8-dibromo 1,10-phenanthroline ligands

Three novel Cd(II) complexes, formulated as [Cd(3,8-dibromo-1,10-phen-κ2N,N′)(l-tar)]n (1), trans-[Cd(3,8-dibromo-1,10-phen-κ2N,N′)2(NO3-κ2O,O′)2]·(CH3CN) (2) and cis-[Cd(3,6-dibromo-1,10-phen-κ2N,N′)(3-bromo-1,10-phen-κ2N,N′)(NO3-2O,O′)(CH3OH-κO)](NO3) (3) (phen = phenanthroline, l-tarH2 = l-tartaric acid), have been synthesized and characterized in this paper. In coordination polymer 1, the [Cd2(3,8-dibromo-phen)2]4+ cations are bridged by l-tar ligands into an infinite 2D lamellar polymer along the c-axis, and the neighboring 2D polymers are further extended into a 3D supramolecular network by π–π stacking interactions. Complexes 2 and 3 are both mononuclear cadmium complexes but with different conformation (trans or cis). In the crystal packing structures of 2 and 3, molecules are arranged into three-dimensional (3D) frameworks by intermolecular hydrogen bonding and π–π stacking interactions.