Palladium (II), platinum (II) and silver (I) complexes with oxazolines: Their synthesis, characterization, DFT calculation, molecular docking and antitumour effects

Abstract

Six new Pd(II), Pt(II) and Ag(I) complexes, (1);{Pd (L1)]2C6H4}2Cl4} (2); Pt(L2)(DMSO)Cl; 3; {PtL5]2C6H4}2·PhCOO-⋅11NO3-; 4; {[Pt(L4)]2C6H4}; the binuclear cyclometalated complex the polymer chain (5); {[PtL5]C6H4}·NO3-}; and the polymeric silver species (6); Zn(L6)2·AgNO3·CHCl3 were synthesized and thoroughly characterized using X-ray diffraction and spectroscopic techniques (L1=(S,S)-1,4-i-PrOx]2C6H4}2Cl4, L2=Di(2,2-bis(4R-isopropyl-4,5-dihydro-oxazol-2-yl)acetonitrile) zinc (II) (BR1);L3= 1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)benzene (AR2); L4= 1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)benzene，L5=1,4-bis(4R-benzyl-4,5-dihydro-oxazol-2-yl)-benzene，L6=Di(2,2-bis(4S-isopropyl-4,5-dihydrooxazol-2-yl)acetonitrile) zinc (II).Complexes 1-6 showed cytotoxic effects against human tumour cell lines, including a multidrug-resistant subline. Oxazoline and Pd complex 1 induced apoptosis in A549 cells. DFT calculations were also performed to exhibit the excellent bioactivity of complex 1 against A549, MDA-MB-231, and KB cells. Complex 1, with the best docking score and a stable interaction network within the binding site of the G-quadruplex, could stably interact with the G-quadruplex. Additionally, complex 1 was further used in the animal experiment of human lung adenocarcinoma cells in nude mice. By comparing with the model control group, the tumour volume, relative tumour volume and relative tumour proliferation rate T/C decreased significantly in the cisplatin group and compound 1 (complex 1) group.