IR Fingerprints of U(VI) Nitrate Monoamides Complexes: A Joint Experimental and Theoretical Study

Piperazinyl-Based Diamide Ligand for Selective Precipitation of Actinyl (UO22+/PuO22+) Ions with Fast Kinetics

A novel ligand N,N'-bis(N″,N″-diethyl carbamoyl) piperazine (BDECP), L1, is synthesized as a selective precipitant for hexavalent actinyl (UO₂²⁺ and PuO₂²⁺) ions from an aqueous nitric acid medium. The ligand BDECP forms an infinite one-dimensional coordination polymer with uranyl nitrate and behaves as a bridging bidentate neutral donor. There is an alternate repetition of [UO₂(NO₃)₂] and BDECP units as evidenced by single-crystal X-ray diffraction. Uranyl ion (UO₂²⁺) can be precipitated in >99% yield from an aqueous nitric acid medium. L1 shows fast kinetics of precipitation of uranyl ion as compared to those of other reported ligands like N-alkyl pyrolidone and N-(1-adamantyl) acetamide. Avrami's coefficient, obtained from the Avrami-Erofe'ev equation, shows that the precipitation mechanism is controlled by the phase boundary and not governed by diffusion. Theoretical studies of the uranyl complex of L1 show that there is no thermodynamic preference for L1 as compared to other potential amide-based precipitants. The principal factors that govern the fast kinetics of precipitation are the aqueous solubility and higher charge density on the amide oxygen of L1.

Synthesis, DNA and BSA binding, in vitro anti-proliferative and in vivo anti-angiogenic properties of some cobalt(iii) Schiff base complexes

In the recent times metal complexes with dual mechanisms of action, anti-cancer and anti-angiogenic, have gained substantial interest in the field of medicinal chemistry.

Uranium adsorption from sulfuric acid media using silica materials functionalised with amide and phosphorous ligands

Identification of functional groups grafted onto silica supports to provide a promising uranium extraction capacity and a high selectivity versus iron.

Reaction mechanism and chemoselectivity of intermolecular cycloaddition reactions between phenyl-substituted cyclopropenone ketal and methyl vinyl ketone

In this paper, the mechanisms of the intermolecular [3+2] and [1+2] cycloaddition reactions of 1,1/1,3-dipolar π-delocalized singlet vinylcarbenes, which is obtained from cyclopropenone, with an electron-deficient C═O or C═C dipolarophile, to generate five-membered ring products are first disclosed by the density functional theory (DFT). Four reaction pathways, including two concerted [3+2] cycloaddition reaction pathways and two stepwise reaction pathways (an initial [1+2] cycloaddition and then a rearrangement from the [1+2] cycloadducts to the final [3+2] cycloadducts), are investigated at the B3LYP/6-31G(d,p) level of theory. The calculated results reveal that, in contrast to the concerted C═O [3+2] cycloaddition reaction pathway, which is 7.1 kcal/mol more energetically preferred compared with its stepwise reaction pathway, the C═C dipolarophile favors undergoing [1+2] cycloaddition rather than concerted [3+2] cycloaddition (difference of 5.3 kcal/mol). The lowest free energy barrier of the C═O concerted [3+2] cycloaddition reaction pathway shows that it predominates all other reaction pathways. This observation is consistent with the finding that the C═O [3 + 2] cycloadduct is the main product under experimental conditions. In addition, natural bond orbital second-order perturbation charge analyses are carried out to explain the preferred chemoselectivity of C═O to the C═C dipolarophile and the origins of cis-stereoselectivity for C═C [1+2] cycloaddition. Solvent effects are further considered at the B3LYP/6-31G(d,p) level in the solvents CH(3)CN, DMF, THF, CH(2)Cl(2), toluene, and benzene using the PCM model. The results indicate that the relative reaction trends and the main products are insensitive to the polarity of the reaction solvent.