Synthesis, crystal structure, antiproliferative activity, DNA binding and density functional theory calculations of 3-(pyridin-2-yl)-8-tert-butylcoumarin and its copper(II) complex

A Cu(II)-coumarin complex, [CuL2(NO3)(2)] (2), where L = 3-(pyridin-2-yl)-8-tert-butylcoumarin (1), was synthesized with Cu(NO3)(2).3H(2)O and characterized using elemental, infrared and single-crystal X-ray diffraction analyses. The crystal structure of1shows that all the pyrone, benzene and pyridine rings are completely coplanar. The crystal structure of2is stabilized by intermolecular C-H...O and C-H...N hydrogen bonds and C...C short contacts, which lead to the formation of a two-dimensional network structure. Density functional theory results give support to the experimentally determined monomeric structure. Thein vitrocytotoxic activities of1and2were investigated against HeLa (cervical carcinoma), A549 (lung), HepG2 (liver) and HUVEC (umbilical vein) cells by MTT assay. The IC(50)values show that both1and2have lower toxicity than doxorubicin and cisplatin in every case. Ligand1exhibits higher anti-HeLa activity than doxorubicin. Complex2displays higher anti-HeLa activity than coumarin but lower than that of cisplatin. Various spectroscopic approaches indicate that1and2could effectively bind with DNA through intercalation mode.