Some new water soluble complexes [N,N′-bis{5-[(triphenyl phosphonium chloride)-methyl]salicylidine}-3,4-diaminopyridine] M(II), which are formulated as nano-[Zn(5-CH₂PPh₃-3,4-salpyr)](ClO₄)₂ (1), [Zn(5-CH₂PPh₃-3,4-salpyr)](ClO₄)₂ (2), nano-[Ni(5-CH₂PPh₃-3,4-salpyr)](ClO₄)₂ (3), [Ni(5-CH₂PPh₃-3,4-salpyr)](ClO₄)₂ (4), and [N,N′-bis{5-[(triphenyl phosphonium chloride)-methyl]salicylidine}-2,3-diaminopyridine]Ni(II) [Ni(5-CH₂PPh₃-2,3-salpyr)](ClO₄)₂ (5) have been isolated and characterized by elemental analysis, FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR, and UV-vis spectroscopy. The morphology and size of the nano complexes were determined using FE-SEM and TEM. In vitro DNA binding studies were investigated by UV-vis absorption spectroscopy, viscosity measurements, CD spectroscopy, cyclic voltammetry, emission spectra and gel electrophoresis, which suggest that the metal complexes act as efficient DNA binders. The absorption spectroscopy of the compounds with DNA reveals that the DNA binding affinity (K_b) has this order: 3 > 4 > 5 > 1 > 2 > Ligand. The metal complexes show DNA binding stronger than the ligand, which is expected due to the nature of the metal. The nano complexes display DNA binding stronger than the other complexes which is related to the effect of size on binding affinity and the Ni(II) complexes reveal DNA binding stronger than the corresponding Zn(II) analogues, which is expected due to their z* effect and geometry. The prominent double strand DNA cleavage abilities of compound 3 are observed in the absence of H₂O₂ with efficiencies of more than 50% even at 70 μM complex concentration. Surprisingly, Zn(II) complexes (compounds 1 & 2) exhibit a higher cytotoxicity (IC₅₀: 7.3 & 10.9 μM at 24 h; IC₅₀: 4.6 & 8.7 μM at 48 h) against human hepatoma (HepG2) and HeLa cell lines than the Ni(II) complexes (compounds 3, 4 & 5) and 5-fluorouracil as control in spite of their inability to cleave DNA. Finally, DNA binding interactions were performed by docking studies. Density functional theory (DFT) studies were performed using the GAUSSIAN 03 program. The DFT method with B3LYP functional, LANL2DZ basis set for metal centers and 6-311g* for other atoms was used. The synthesized compounds and DNA were simulated by molecular docking to explore more details of the ligands conformation and their orientations in the active site of the receptor.

A new nano tetraimine Pd(0) complex was successfully prepared by the complexation of palladium acetate with an N,N-bisimine ligand. The structural features of the catalyst and the ligand were characterized using different microscopic and spectroscopic techniques such as FT-IR, XRD, XPS, UV–Vis, NMR, and elemental analysis. The morphology of the catalyst was determined using FE-SEM and TEM. The catalyst was effectively employed in the palladium-catalyzed Heck–Mizoroki reaction in water as a green solvent. The catalyst was reusable and recycled six times without any decrease in its catalytic activity. The ICP analysis showed that the catalyst has very little Pd leaching (0.2%) during the reaction process, demonstrating that our catalyst is stable and heterogeneous in practice. Furthermore, we have theoretically explored the feasibility of two neutral and cationic pathways in the density functional theory framework. The geometries and energies of all species involved in the reaction mechanism are analyzed.

A highly efficient and easily recyclable magnetic nanoparticle supported palladium catalyst was developed and applied in the Heck and Sonogashira reactions in order to show its catalytic applicability in Pd-catalyzed C–C coupling protocols. The catalyst was prepared using a simple chemical process. First, the prepared Fe₃O₄@SiO₂ nanoparticles were reacted with (3-chloropropyl)-trimethoxysilane (3-CPTMS) in order to synthesis chloro-functionalized magnetic nanoparticles (CPS-MNPs). The substitution reaction of synthetic NNN ligand with CPS-MNPs yields the production of CPS-MNPs–NNN ligand. Finally, immobilization of palladium species on CPS-MNPs–NNN ligand surface afforded CPS-MNPs–NNN–Pd catalyst. The structure and morphology of the prepared nanocatalyst was characterized using various methods such as SEM, TEM, XPS, EDX, CHN, ICP, XRD, FT-IR and VSM techniques. The TEM images show that the sizes of the palladium catalyst are in the range of 8–15 nm. The Heck and Sonogashira coupling reactions were performed in the presence of a catalytic amount of this catalyst system (0.5 mol%) and good yields of products were obtained. Due to the magnetic nature of the catalyst it can be separated from the reaction mixture easily by applying an external magnetic field. Heterogeneity tests affirmed that the catalytic activity stayed indefectible during multiple reaction cycles.