Two New Nickel(II) Complexes of (4-Amino-1,2,4-triazole-3,5-diyldithio)diacetic Acid: Syntheses, Crystal Structures and Characterizations

Abstract

Two new complexes [Ni(phen)(H ₂ O) ₄ ] · (atda)(H ₂ O) ₅ (1) and [Ni ₂ (4,4′ -bipy) ₂ (H ₂ O) ₈ ] · (atda) ₂ (2) (where H ₂ atda = (4-amino-1,2,4-triazole-3,5-diyldithio)diacetic acid, phen = 1,10-phenanthroline, 4,4′ -bipy = 4,4′ -bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, thermogravimetric analysis and X-ray diffraction technique. X-ray structural analyses reveal that the two complexes are both three-dimensional (3D) supramolecular structures and possess similar structural characters. The Ni(II) centers are both in distorted octahedral coordination environments, six-coordinated by four water molecules and two nitrogen atoms from a 1,10-phenanthroline molecule or two 4,4′ -bipyridine molecules. The atda ^{2 −} ligands do not coordinate to the Ni(II) centers, but only exist as counter anions, forming hydrogen bonds with coordinated or uncoordinated water molecules. Various hydrogen-bonding interactions play an important role in the assembly of three-dimensional supramolecular architectures.

Keywords:

• crystal structure
• flexible carboxylate ligand
• Ni(II) complexes
• supramolecular compounds