Synthesis, characterization, anti-bacterial and anticancer activities of Palladium(II) mixed ligand complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole (HmtzS) and phosphines. Crystal structure of [Pd(mtzS)2(dppf)].H2O.EtOH

Spectroscopic, anti-cancer, anti-bacterial and theoretical studies of new bivalent Schiff base complexes derived from 4-bromo-2,6-dichloroaniline

In this paper, four new mono-nuclear Ni(II), Pd(II), Pt(II) and Zn(II) complexes were prepared by using a bi-dentate Schiff base ligand, (E)-2-(((4-bromo-2,6-dichlorophenyl)imino)methyl)-5-chlorophenol (BrcOH), with bivalent ions in a methanol and distil water mixture as solvent in presence of NaOH as base. The structures of the prepared compounds were characterized by spectroscopic techniques (IR and 1H NMR), CHN analysis, and molar conductivity. The M(II) (Ni, Pd and Pt) ions are four-coordinated by a bi-dentate N2O2 donor ligand, forming square planar geometry, whereas the Zn(II) is coordinated as a tetrahedral geometry. The newly synthesized compounds, which include the Schiff base ligand and its complexes, underwent antibacterial screening against E. coli and S. aureus. The results demonstrated a remarkable and noteworthy biological activity of these compounds against these pathogenic bacterial strains. Different binding energies showed good correlation, with Pd showing the strongest binding. Small energy differences indicated high reactivity, with Ni and Pd complexes being the most reactive. Electrophilicity index exhibited electron-accepting properties, with Zn showing the highest reactivity. The dipole moments showed polarity and charge separation, with Pt having the highest polarity. We evaluated the pharmacokinetic properties (ADME) of a ligand and its metal complexes using the Swiss ADME website. The results of the in-silico prediction of physicochemical properties revealed that ten compounds in total adhered to Lipinski's rule.

Functionalization of 2-Mercapto-5-methyl-1,3,4-thiadiazole: 2-(ω-Haloalkylthio) Thiadiazoles vs. Symmetrical Bis-Thiadiazoles

A study on the functionalisation of 2-mercapto-5-methyl-1,3,4-thiadiazole has been conducted, yielding two series of products: 2-(ω-haloalkylthio)thiadiazoles and symmetrical bis-thiadiazoles, with variable chain lengths. The experimental conditions were optimised for each class of compounds by altering the base used and the reagents' proportions, leading to the development of separate protocols tailored to their specific reactivity and purification needs. The target halogenide reagents and bis-thiadiazole ligands were obtained either as single products or as mixtures easily separable by chromatography. Characterisation of the products was performed using 1D and 2D NMR spectra in solution, complemented by single crystal X-ray diffraction (XRD) for selected samples, to elucidate their structural properties.

Spectroscopic, Anti-Cancer Activity, and DFT Computational Studies of Pt(II) Complexes with 1-Benzyl-3-phenylthiourea and Phosphine/Diamine Ligands

The reaction between [PtCl2(L-L)] (L-L = dppe, dppp, dppb, dppf, Phen and Bipy) or [PtCl2(PPh3)2] with 1-benzyl-3-phenylthiourea (H2BPT) in a basic medium (CHCl3/EtOH) created new coordinated square planner Pt(II) complexes with [Pt(BPT)(L-L)] (1–4,6,7) and [Pt(BPT)(PPh3)2] (5) types. These complexes were fully characterized by analytical and spectroscopic techniques (i.e., IR, UV. Vis., 1H, and 31P NMR). The results indicated that the thiourea derivative ligand act as a dianion ligand bonded through both S and N atoms in a chelating mode or as a mono-anion ligand coordinated through a sulfur atom with Pt(II) ion. Cytotoxicity activity was performed by the MTT assay to determine anti-cancer activities against MCF-7 breast cancer cells. The study indicated that IC50 values for MCF-7 cells were 10.96–78.90 µM. Additionally, the complexes [Pt(BPT)(dppe)] (1), [Pt(BPT)(PPh3)2] (5), and [Pt(BPT)2(Bipy)] (7) were investigated theoretically, where their quantum parameters were evaluated using the Gaussian 09 program using the theory of B3LYP/Def2TZVP//B3LYP/Lanl2dz. The calculation results confirmed the optimized structures of the complexes square planar geometry. However, the calculated bond lengths and angles showed a slightly distorted square planar geometry due to the trans influence of the sulfur atom. Additionally, complexes of [Pt(BPT)(dppe)] (1) and [Pt(BPT)(PPh3)2] (5) showed higher stability compared to [Pt(BPT)2(Bipy)] (7), which can be attributed to the higher back-donation of (1) and (5) complexes. Furthermore, among the three complexes, the [Pt(BPT)2(Bipy)] (7) complex possessed the lowest HOMO–LUMO gap, which may be a good candidate as the photo-catalyst material.

Cd(II) and Pd(II) Mixed Ligand Complexes of Dithiocarbamate and Tertiary Phosphine Ligands-Spectroscopic, Anti-Microbial, and Computational Studies

Mixed ligand complexes of Pd(II) and Cd(II) with N-picolyl-amine dithiocarbamate (PAC-dtc) as primary ligand and tertiary phosphine ligand as secondary ligands have been synthesized and characterized via elemental analysis, molar conductance, NMR (1H and 31P), and IR techniques. The PAC-dtc ligand displayed in a monodentate fashion via sulfur atom whereas diphosphine ligands coordinated as a bidentate mode to afford a square planner around the Pd(II) ion or tetrahedral around the Cd(II) ion. Except for complexes [Cd(PAC-dtc)2(dppe)] and [Cd(PAC-dtc)2(PPh3)2], the prepared complexes showed significant antimicrobial activity when evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Moreover, DFT calculations were performed to investigate three complexes {[Pd(PAC-dtc)2(dppe)](1), [Cd(PAC-dtc)2(dppe)](2), [Cd(PAC-dtc)2(PPh3)2](7)}, and their quantum parameters were evaluated using the Gaussian 09 program at the B3LYP/Lanl2dz theoretical level. The optimized structures of the three complexes were square planar and tetrahedral geometry. The calculated bond lengths and bond angles showed a slightly distorted tetrahedral geometry for [Cd(PAC-dtc)2(dppe)](2) compared to [Cd(PAC-dtc)2(PPh3)2](7) due to the ring constrain in the dppe ligand. Moreover, the [Pd(PAC-dtc)2(dppe)](1) complex showed higher stability compared to Cd(2) and Cd(7) complexes which can be attributed to the higher back-donation of Pd(1) complex.