A novel one-dimensional coordination polymer of cadmium(II)/triazine extending by di-chloro and di-iodo bridges

A new triazine ligand salt, 2,2′,2″-(1,3,5-triazine-2,4,6-triyl)tris(hydrazin-1-ium) chloride [THT·(HCl)₃], and the one-dimensional coordination polymer of cadmium, [Cd₂(µ-THT)(µ-Cl)(µ-I)I₂]·2(H₂O), are prepared and characterized by elemental analysis, Fourier-transform infrared spectroscopy, 1H NMR spectroscopy, and single-crystal X-ray diffraction (for the cadmium polymer). X-ray analysis revealed that the polymeric backbone is extended alternatively by di-iodo and di-chloro bridges; this type of bridge is not observed previously between any metal atoms. There are two types of cadmium atoms in the polymer: cadmium of the polymeric chain and terminal cadmiums. The geometry around the first (CdN₂Cl₂I₂) is octahedral, while the latter (CdN₃I₂) has an incline to square-pyramidal geometry. The triazine ligand of this structure also bridges two cadmium atoms and acts as an N₃ donor toward the terminal cadmium atoms and as an N₂ donor toward the cadmium atoms of the chain. In the crystal network of the cadmium polymer, the hydrogen bonds of N–H···X (X: O, N, I) form different hydrogen bond motifs, including R22(8), R24(10), R34(14), R44(18), R46(20), R66(24), R66(28), and R66(32).