Synthesis, cytotoxic, antibacterial, antioxidant activities, DFT, and docking of novel complexes of Palladium (II) containing a thiourea derivative and diphosphines

A thiourea ligand; N, N-di-(4-tolyl)-N'-(6-chloronicotinoyl) thiourea (LH) was synthesized from the reaction of 6-chloronicotinyl chloride with potassium thiocyanate which gave 6-chloronicotinoyl isothiocyanate, then reaction of 6-chloronicotinoyl isothiocyanate with Di-p-tolylamine in acidic medium gave the desired ligand (LH). Treatment of LH with K2PdCl4 gave a complex of [Pd(L)2]1. Reaction of complex 1 with each of Ph2P(CH2)2PPh2 (dppe) and Ph2P(CH2)3PPh2 (dppp) yielded complexes of the types [Pd(II)(L)2(Ph2P(CH2)2PPh2)]2 and [Pd(II) (L)2 (Ph2P(CH2)3PPh2)]3, respectively. Treating complexes 2 and 3 with some transition metals gave hetero binuclear complexes [(Ph2P(CH2)2 PPh2) Pd(II)(mu-L)2MCl2(H2O)x] (where x= 0 or 2 and M = Zn(II), Cd(II) or Co (II)) and [(Ph2P(CH2)3 PPh2)Pd(II)(mu-L)2 MCl2 (H2O)x] (where x=0 or 2, and M= Cd(II), or Co(II)). 13CNMR , 13C-NMR, 1H-{31P}-NMR, 31P{1H}-NMR, FTIR spectroscopy, microelemental analysis (CHNS), magnetic sus-ceptibility, thermogravimetric analysis (TGA), mass spectra, and ultraviolet-visible spectroscopy were all employed to characterize the ligand and all of the synthesized metal complexes. The ligand and all the prepared complexes were tested for their antibacterial, antioxidant, and anticancer activities. Complexes 2, 3, and 6 showed various antibacterial activities against Staphylococcus aureus and Staphylococcus sciuri with no inhibitory effect on Escherichia coli. Whereas complexes 6, and 8 showed moderate antioxidant activity. Complexes 3, and 6 exhibited moderate cytotoxicity toward CEMSS leukemia cancer cells. Collectively, these outcomes suggest that these metal complexes can be developed into a new therapy with many biological activities for the treatment of various human ailments. The density functional theory (DFT) was used to optimize complex 6 and obtained geometrical parameters for its structural analysis. Molecular docking (MD) of complex 6 with the target protein of human cancer cells (3UZE) was achieved. It may be of interest for researchers to focus on designing and producing novel anticancer medications based on palladium complexes instead of platinum complexes.