Ekaterina Oleneva, Julia Savosina, Marina Agafonova-Moroz, Alexander Lumpov, Vasily Babain, Igor Jahatspanian, Andrey Legin, Dmitry Kirsanov, Potentiometric multisensor system for tetra- and hexavalent actinide quantification in complex rare earth metal mixtures related to spent nuclear fuel reprocessing, Sensors and Actuators B: Chemical, 2019, 288, 155-162. DOI: 10.1016/j.snb.2019.02.113

Abstract

A potentiometric multisensor system, composed of 12 cross-sensitive sensors, is proposed for uranium and thorium quantification in multi-component mixtures simulating PUREX process tailing solutions. Various ligands with high extraction capacity to lanthanides and actinides were used as active compounds in plasticized polymeric sensor membranes. The sensitivity of the individual sensors to tetra- and hexavalent actinides (UO₂²⁺ and Th⁴⁺) in aqueous nitric acid solutions with pH = 2 has been studied for the first time. The sensors with pronounced sensitivity to actinides were comprised into the multisensor system that was applied for UO²⁺₂and Th⁴⁺ quantitative determination in presence of each other and lanthanides cations (La³⁺, Pr³⁺, Sm³⁺, Gd³⁺, Yb³⁺). The nitric acid quantification in the set of mixtures with UO²⁺₂ and La³⁺ was also performed using the same system. Projection on latent structures (PLS) algorithm was used for multivariate regression models calculation. The results of PLS models validation with independent test set show the possibility of UO²⁺₂ and Th⁴⁺ quantification with mean relative error (MRE) equal to 17% and 14% correspondingly, and HNO₃ quantification with MRE = 7%. This accuracy is appropriate for real-time technological control of PUREX process.

Gomathy Chakkaradhari, Toni Eskelinen, Cecilia Degbe, Andrey Belyaev, Alexey S. Melnikov, Elena V. Grachova, Sergey P. Tunik, Pipsa Hirva, and Igor O. Koshevoy, Oligophosphine-thiocyanate Copper(I) and Silver(I) Complexes and Their Borane Derivatives Showing Delayed Fluorescence, Inorg. Chem., 2019. DOI: 10.1021/acs.inorgchem.8b03166

Abstract

The series of chelating phosphine ligands, which contain bidentate P² (bis[(2-diphenylphosphino)phenyl] ether, DPEphos; 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, Xantphos; 1,2-bis(diphenylphosphino)benzene, dppb), tridentate P³ (bis(2-diphenylphosphinophenyl)phenylphosphine), and tetradentate P⁴ (tris(2-diphenylphosphino)phenylphosphine) ligands, was used for the preparation of the corresponding dinuclear [M(μ₂-SCN)P²]₂ (M = Cu, 1, 3, 5; M = Ag, 2, 4, 6) and mononuclear [CuNCS(P³/P⁴)] (7, 9) and [AgSCN(P³/P⁴)] (8, 10) complexes. The reactions of P⁴ with silver salts in a 1:2 molar ratio produce tetranuclear clusters [Ag₂(μ₃-SCN)(t-SCN)(P⁴)]₂ (11) and [Ag₂(μ₃-SCN)(P⁴)]₂²⁺ (12). Complexes 7–11 bearing terminally coordinated SCN ligands were efficiently converted into derivatives 13–17 with the weakly coordinating ^–SCN:B(C₆F₅)₃ isothiocyanatoborate ligand. Compounds 1 and 5–17 exhibit thermally activated delayed fluorescence (TADF) behavior in the solid state. The excited states of thiocyanate species are dominated by the ligand to ligand SCN → π(phosphine) charge transfer transitions mixed with a variable contribution of MLCT. The boronation of SCN groups changes the nature of both the S₁ and T₁ states to (L + M)LCT d,p(M, P) → π(phosphine). The localization of the excited states on the aromatic systems of the phosphine ligands determines a wide range of luminescence energies achieved for the title complexes (λ_em varies from 448 nm for 1 to 630 nm for 10c). The emission of compounds 10 and 15, based on the P⁴ ligand, strongly depends on the solid-state packing (λ_em = 505 and 625 nm for two crystalline forms of 15), which affects structural reorganizations accompanying the formation of electronically excited states.

Kristina S. Kisel, Alexei S. Melnikov, Elena V. Grachova, Antti J. Karttunen, Antonio Doménech-Carbó, Kirill Yu. Monakhov, Valentin G. Semenov, Sergey P. Tunik, and Igor O. Koshevoy, Supramolecular Construction of Cyanide-Bridged Re^I Diimine Multichromophores, Inorg. Chem., 2019, 58 (3), pp 1988–2000. DOI: 10.1021/acs.inorgchem.8b02974

Abstract

The reactions of labile [Re(diimine)(CO)₃(H₂O)]⁺ precursors (diimine = 2,2′-bipyridine, bpy; 1,10-phenanthroline, phen) with dicyanoargentate anion produce the dirhenium cyanide-bridged compounds [{Re(diimine)(CO)₃}₂CN)]⁺ (1 and 2). Substitution of the axial carbonyl ligands in 2 for triphenylphosphine gives the derivative [{Re(phen)(CO)₂(PPh₃)}₂CN]⁺ (3), while the employment of a neutral metalloligand [Au(PPh₃)(CN)] affords heterobimetallic complex [{Re(phen)(CO)₃}NCAu(PPh₃)]⁺ (4). Furthermore, the utilization of [Au(CN)₂]⁻, [Pt(CN)₄]^2–, and [Fe(CN)₆]^4–/3– cyanometallates leads to the higher nuclearity aggregates [{Re(diimine)(CO)₃NC}_xM]^m+ (M = Au, x = 2, 5 and 6; Pt, x = 4, 7 and 8; Fe, x = 6, 9 and 10). All novel compounds were characterized crystallographically. Assemblies 1–8 are phosphorescent both in solution and in the solid state; according to the DFT analysis, the optical properties are mainly associated with charge transfer from Re tricarbonyl motif to the diimine fragment. The energy of this process can be substantially modified by the properties of the ancillary ligands that allows to attain near-IR emission for 3 (λ_em = 737 nm in CH₂Cl₂). The Re–Fe^II/III complexes 9 and 10 are not luminescent but exhibit low energy absorptions, reaching 846 nm (10) due to Re^I → Fe^IIItransition.