Supramolecular association involving antiparallel CO⋯CO and anion–π contacts in Co(II) and Mn(II) complexes involving 2,5-pyridinedicarboxylate: Anticancer evaluation and theoretical studies

Abstract

Two new coordination solids viz. [Co(2,5-PDC)(H2O)4] 2H2O (1) and [Mn(2,5-PDC)(H2O)4] 2H2O [2,5-PDC = 2,5-pyridinedicarboxylat] (2) have been synthesized and characterized by Single crystal X-ray analysis, FT-IR, electronic spectra and TGA. Single-crystal X-ray diffraction studies reveal that compounds 1 and 2 are isostructural and extensive OH⋯O hydrogen bonds along with CH⋯O and anion⋯π interactions stabilize the crystal structures. The lattice water molecules are responsible for the 3D framework of the complexes. The remarkable combination of OH⋯O, anion–π and antiparallel CO⋯CO interactions observed in the solid state structures have been analyzed by means of DFT calculations, molecular electrostatic potential (MEP) surface and non-covalent interaction (NCI plot) index computational tools. The anticancer activity of synthesized complexes has been studied in Dalton’s lymphoma (DL) cell line using MTT based cytotoxicity study, fluorescence based apoptosis study, molecular docking and pharmacophore modeling. Both complexes significantly (P ≤ 0.05) induced cytotoxicity through apoptotic cell death in DL cells with negligible cytotoxicity (∼5–10%) in normal blood cells. It is worth mentioning that compounds 1 and 2 interact with highly expressed anti-apoptotic cancer target proteins under study with higher binding affinity and the results are comparable with respective reference inhibitors. Moreover, both complexes also bear significant pharmacophore features such as H-bond donor and acceptor, aromatic and hydrophobic sites which are responsible for anticancer activities.