Two new neutral copper(II) complexes with dipicolinic acid and 3-amino-1H-1,2,4-triazole formed under different reaction conditions: synthesis, characterization, molecular structures and DNA-binding studies.

Two Cu(II) complexes, [Cu₂(μ-atr)(pydc)₂(H₂O)₄]·5H₂O (1) and [Cu(atr)(pydc) (H₂O)]·H₂O (2), with pyridine-2,6-dicarboxylic acid (H₂pydc) and 3-amino-1H-1,2,4-triazole (atr), have been synthesized and characterized. The interaction ability of the both complexes with native calf thymus DNA (CT-DNA) has been monitored as a function of the metal complex-DNA molar ratio. UV-vis spectrophotometry, circular dichroism (CD), thermal denaturation studies, cyclic voltammetry (CV) and viscosity measurements.

Bis(2,6-diamino-pyridinium) bis-(pyridine-2,6-dicarboxyl-ato)zincate(II) monohydrate.

In the title hydrated mol-ecular salt, (C(5)H(8)N(3))(2)[Zn(C(7)H(3)NO(4))(2)]·H(2)O, the Zn(II) atom is coordinated by two O,N,O'-tridentate pyridine-2,6-dicarboxyl-ate dianions, generating a slightly distorted trans-ZnN(2)O(4) octa-hedral coordination geometry for the metal ion. In the crystal, a network of O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds involving the cations, anions and water mol-ecules results in a three-dimensional network.