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2,6-Bis(5,6-dialkyl-1,2,4-triazin-3-yl)-pyridine (R-BTP) is one of the most promising classes of soft N-donor ligands for minor trivalent actinide (such as Am(iii) and Cm(iii)) separation but its complexation behavior with interfering element Pd(ii) is still unknown. The effect of substituents (R-) on the modulation of R-BTP's complexation with Pd(ii) was studied by single crystal diffractometry, 1H NMR spectroscopy, ESI-MS, and density functional theory (DFT) calculation methods. The formation of both 1 : 1 and 2 : 1 complexes of R-BTP with Pd(ii) were firstly identified, and their electronic and geometric structures were determined. It has been found that the modification of the R-BTP skeleton with substituents (R-) changing from methyl (C1) to s-butyl (C4) leads to two different coordination models with water. The structures of 2 : 1 R-BTP/Pd(ii) complexes were determined to be unusually paramagnetic, distorted six-coordinate compounds. However, the 1 : 1 species was found to have a typical square-planar geometry. The extraction properties of four R-BTPs for Pd(ii) and other fission or corrosion products were studied. This work can help to further understand the complexation behavior of Pd(ii) with R-BTP, which provides theoretical insights into the partitioning of minor actinides and Pd(ii) from high level active waste (HLW) using R-BTP type ligands. [ABSTRACT FROM AUTHOR]

A novel mesoporous polymer-based composite, C7-BTBP/XAD-7, was prepared by impregnating 6,6’-bis(5,6-diheptyl-1,2,4-triazin-3-yl)-2,2’-bipyridine (C7-BTBP) into the pores of the polymeric XAD-7 carrier. The microstructure of the material was characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherms, and thermogravimetric analysis (TGA). The selective adsorption of Pd(II) onto C7-BTBP/XAD-7 from a HNO3medium containing some typical metals, including Ru(III), Fe(III), Mo(VI), Zr(IV), Li(I), Na(I), K(I), Rb(I), Cs(I), Mg(II), Ca(II), Sr(II), Ba(II), Y(III), La(III), Nd(III), and Yb(III), was investigated. The polymeric composite exhibited strong adsorption affinity, high selectivity, and fast adsorption rate for Pd(II) in 3.0 M HNO3. The adsorption isotherm fitted well with Langmuir model, with a maximum adsorption capacity of 0.412 mmol/g. The hybrid polymeric composite was very stable in HNO3solution. The kinetics of Pd(II) coordinated with C7-BTBP was discussed by Density Function Theory (DFT) calculations. [ABSTRACT FROM PUBLISHER]