Synthesis, crystal structure, antiproliferative activity, DNA binding and density functional theory calculations of 3‐(pyridin‐2‐yl)‐8‐<i>tert</i>‐butylcoumarin and its copper(II) complex
Wen Lu, Jiuzhou Shi, YingFang Nie, Lu Yang, Jichao Chen, Fengyi Zhao, Shilong Yang, Li Xu, Xingwei Chi
Abstract
A Cu(II)–coumarin complex, [CuL 2 (NO 3 ) 2 ] ( 2 ), where L = 3‐(pyridin‐2‐yl)‐8‐ tert ‐butylcoumarin ( 1 ), was synthesized with Cu(NO 3 ) 2 ⋅3H 2 O and characterized using elemental, infrared and single‐crystal X‐ray diffraction analyses. The crystal structure of 1 shows that all the pyrone, benzene and pyridine rings are completely coplanar. The crystal structure of 2 is 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. The in vitro cytotoxic activities of 1 and 2 were investigated against HeLa (cervical carcinoma), A549 (lung), HepG2 (liver) and HUVEC (umbilical vein) cells by MTT assay. The IC 50 values show that both 1 and 2 have lower toxicity than doxorubicin and cisplatin in every case. Ligand 1 exhibits higher anti‐HeLa activity than doxorubicin. Complex 2 displays higher anti‐HeLa activity than coumarin but lower than that of cisplatin. Various spectroscopic approaches indicate that 1 and 2 could effectively bind with DNA through intercalation mode.