Synthesis and structure of a new trinuclear nickel(II) complex bridged by N‐[3‐(Dimethylamino)propyl]‐N′‐(2‐hydroxyphenyl)oxamido: in vitro anticancer activities,and reactivities toward DNA and protein

A new trinickel(II) complex bridged by N‐3‐(dimethylamino)propyl]‐ N ′‐(2‐hydroxylphenyl)oxamido (H₃pdmapo), namely Ni₃(pdmapo)₂(H₂O)₂]?4CH₃OH, was synthesized and characterized by X‐ray single‐crystal diffraction and other methods. In the molecule, two symmetric cis‐ pdmapo^3? mononickel(II) complexes as a “complex ligand” using the carbonyl oxygen atoms coordinate to the center nickel(II) ion situated on an inversion point. The Ni···Ni distance through the oxamido bridge is 5.2624(4) Å. The center nickel(II) ion and the lateral ones have octahedral and square‐planar coordination geometries, respectively. In the crystal, a three‐dimensional supramolecular network dominated by hydrogen bonds is observed. The reactivity toward DNA/protein bovine serum albumin (BSA) revealed that the complex could interact with herring sperm DNA (HS‐DNA) through the intercalation mode and quench the intrinsic fluorescence of BSA via a static mechanism. The in vitro anticancer activities suggested that the complex is active against the selected tumor cell lines.