Synthesis, Kinetics, Reaction Mechanism, and Bioactivity Assays of a Dimeric Palladium Complex.

A dimer of Pd(II), [(bpy)Pd(μ-OH)Pd(bpy)], (complex ) (where bpy = 2,2'-bipyridyl) has been synthesized at physiological pH (7.4) and characterized by electronic spectroscopy, electrospray ionization mass spectrometry (ESI-MS) spectroscopy, and Fourier transform infrared (FT-IR) analysis. Reaction kinetics of with glycine (LH), l-glutamic acid (LH), and l-arginine (LH) were investigated in an aqueous medium at pH of 7.4 and constant ionic strength via a spectrophotometer as a function of temperature and different concentrations of substrate-complex and ligand. The interactions were supported by two discrete successive steps, i.e., ligand-dependent and ligand-independent steps. The equilibrium constant of complex formation (outer-sphere association) and the rate constant during complex-substrate-ligand interaction were calculated. The Eyring equation was applied to evaluate activation factors (Δ and Δ), and associative mechanisms of all reactions were proposed. Thermodynamic parameters (Δ° and Δ°) were also estimated from the standard plot of ln against 10/. Spectroscopic titration of at pH 7.4 in Tris-HCl buffer with calf thymus DNA, electronic emission titration with ethidium bromide (EtBr), antimicrobial activities, and an agarose gel electrophoresis run of on pBR322 plasmid DNA have shown strong evidence of anticancer activity. Moreover, it has nontoxic water molecules as leaving groups.