Investigation of the kinetics of formation of 1 : 1 complex between chromium(III) with 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate ion in aqueous acidic media

The kinetics of formation of the 1?:?1 complex of chromium(III) with 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate (1,3-pddadp) were followed spectrophotometrically at λ _max?=?557?nm. The reaction was first-order in chromium(III). Increasing the 1,3-pddadp concentration from 2.2?×?10^?2 to 0.11?mol?dm^?3 accelerated the reaction rate. Increasing the hydrogen ion concentration from 1.995?×?10^?5 to 6.31?×?10^?4 mol?dm^?3 retarded the reaction rate. The reaction rate was also retarded by increasing ionic strength and dielectric constant of the reaction medium. A mechanism was suggested to account for the results obtained which involves ion-pair formation between the various reactants. Values of 22?kJ?mol^?1 and ?115?J?K^?1 mol^?1 were obtained for the energy and the entropy of activation, respectively, which indicate an associative mechanism. The logarithm of the formation constant of the 1?:?1 complex formed was 11.3.     

Synthesis and anticancer property of one Fe(II) compound based on 5-(3-pyridyl)tetrazole-2-acetic acid

Abstract

Tetrazole-carboxylate ligands are universally considered as multi-functional candidates for the construction of coordination architectures. A 1-D [Fe(pytza)₂(H₂O)₂]_n·2nH₂O (pytza = 5-(3-pyridyl)tetrazole-acetato) has been prepared. In vitro study on Hela cells show that Hpytza is naturally nontoxic while [Fe(pytza)₂(H₂O)₂]_n·2nH₂O shows high toxicity with a half-maximal inhibitory concentration (IC₅₀) of 6.3?×?10^?5 M. In addition, the compound can effectively inhibit the migration of Hela cells.     

Pd@GO/Fe3O4/PAA/DCA: a novel magnetic heterogeneous catalyst for promoting the Sonogashira cross-coupling reaction

Abstract

A hybrid system involving graphene oxide (GO), magnetic oxide (Fe₃O₄), acrylamide and dicyandiamide was prepared via amine functionalization of GO/Fe₃O₄ by means of covalent bonding with acrylamide and subsequent reaction with dicyandiamide to provide a multinitrogen containing polymer on the surface of GO. This hybrid system was utilized as a heterogeneous catalyst support for immobilizing Pd nanoparticles to provide the hybrid, Pd@GO/Fe₃O₄/PAA/DCA. This nano-Pd composite was characterized using Fourier transform infrared, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetric analysis, X-ray diffraction, and ICP techniques and used for promoting Sonogashira cross-coupling under mild reaction conditions. This heterogeneous and magnetic catalyst was easily separated by external magnet and was reused in a model reaction, efficiently up to six times with slight loss of catalytic activity and Pd leaching, showing the suitability of GO/Fe₃O₄/PAA/DCA for embedding Pd nanoparticles. To check the effect of the number of surface nitrogens of the polymeric chain on the catalytic performance, the activity of the catalyst was compared with Pd@GO/Fe₃O₄/PAA; increased number of the surface nitrogens on the chain polymer leads to higher loading of Pd and lower the Pd leaching.