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The reaction of [Ln(btfa)3(H2O)2] (btfa− = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate) with additional 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbtfa) and acridine (Acr) in ethanol allows the isolation of the mononuclear compounds HAcr[Nd(btfa)4]·EtOH, (1) and HAcr[Ln(btfa)4], Ln = Dy (2) and Yb (3); HAcr+ = acridinium cation. Magnetic measurements indicate that complexes 1–3 show field-induced single-ion magnet behavior with anisotropy energy barriers and preexponential factors of Ueff = 20.7 cm−1, τ0 = 24.5 × 10−8 s; Ueff = 40.5 cm−1, τ0 = 8.6 × 10−10 s and Ueff = 22.7 cm−1, τ0 = 8.4 × 10−8 s, for 1–3 respectively. The solid-state luminescence emission in the NIR region shows efficient energy transfer from the 4,4,4-trifluoro-1-phenyl-1,3-butanedionate ligands to the central Ln3+ ion in the case of compounds 1 and 3. [ABSTRACT FROM AUTHOR]

Synthesis, structure and properties of two alkali-lanthanide heterometallic coordination polymers with the stoichiometric formula [M(OH)(HO)Ln(NO)] (where M is Na and Ln, Er or Yb) are reported. They crystallize in the monoclinic P2/ c space group with very similar cell parameters: a = 15.8777(19) Å, b = 13.4173(18) Å, c = 13.3515(17) Å, β = 93.585(9)º, and V = 2838.8(6) Å for Er(III) and a = 15.8756(5) Å, b = 13.3707(4) Å, c = 13.3083(4) Å, β = 93.584(2)º, and V = 2819.40(15) Å for the Yb(III) polymer. The main findings in the structures of the new compounds are their isomorphism (due to the similarity between erbium and ytterbium ionic radii) and the coexistence in both of highly aqueous coordinated [Na(OH)(HO)] and [Ln(NO)] units. The luminescence measurements in the near infrared region after excitation at different wavelengths have confirmed the deleterious effect (quenching) of OH and HO groups on the emission (intensity and lifetime) of both erbium(III) and ytterbium(III) and the very weak optical absorption of lanthanides. Magnetic measurements show a paramagnetic behavior of the lanthanide centers. Graphical Abstract: Two new isostructural alkali-lanthanide coordination polymers, [Na(OH)(HO)Er(NO)] and [Na(OH)(HO)Yb(NO)], have been synthesized and characterized by X-ray diffraction. Their photoluminescent and magnetic properties are presented.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: The axially substituted monophthalocyanine complexes of lanthanides are not enough investigated in comparison with sandwich-type phthalocyanine complexes of lanthanides because of their much lower stability in comparison with sandwich-type complexes. In this work, the new methods of obtaining monolithic silica blocks doped with acetato substituted Yb(III) monophthalocyanine complex are reported. The spectroscopic properties of this complex were measured and the results were compared for solution, solid state and xerogels dotted with PcYb(OAc). Besides of the usually observed emission of the phthalocyanines, the emission of the Yb3+ ion in IR region after excitation in phthalocyanine band (674nm) for Yb(III) complex incorporated in silica gel was observed first time. Thus, this result confirms energy transfer in the system under study. The mechanism of energy transfer was proposed. It is worth to notice, that Yb(III) emission was not observed for complex in solution and at solid state. The IR and Raman spectra of ytterbium ion in phthalocyanine complexes are reported and discussed. [ABSTRACT FROM AUTHOR]

The ytterbium(III) extraction kinetics and mechanism with mixtures of bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272) and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) dissolved in heptane have been investigated by constant interfacial cell with laminar flow. The effects of the stirring rate, temperature, extractant concentration, and pH on the extraction with mixtures of Cyanex272 and P507 have been studied. The results are compared with those of the system with Cyanex272 or P507 alone. It is concluded that the Yb(III) extraction rate is enhanced with mixtures extractant of Cyanex272 and P507 according to their values of the extraction rate constant, which is due to decreasing the activation energy of the mixtures. Atthe same time, the mixtures exhibits no synergistic effects for Y(III), which provides better possibilities for Yb(III) and Y(III) separations at a proper conditions than anyone alone. Moreover, thermodynamic extraction separation Yb(III) and Y(III) by the mixtures has been discussed, which agrees with kinetics results. Extraction rate equations have also been obtained, and through the approximate solutions of the flux equation, diffusion parameters and thickness of the diffusion film have been calculated. [ABSTRACT FROM AUTHOR]