Effects of changing the M2+ cation on the crystal structure and optical properties of divalent samarium-doped MAl2Si2O8 (M = Ca, Sr, Ba)

Li, Ling; Liu, Xiaoguang

doi:10.1039/c4ra15391j

Cited by 13 publications

(4 citation statements)

References 30 publications

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“…There are several reports addressing the 4f → 4f photoluminescence of Sm 2+ most of them on Sm 2+ -doped hosts. 37,68,69 However, our assignments deviate from what has been published so far. The assignments in the present work have been performed based on chemical intuition, symmetry, experimental spectra, and theoretical calculations (Table S7).…”

Section: ■ Experimental Sectioncontrasting

confidence: 95%

Influence of Outer-Sphere Anions on the Photoluminescence from Samarium(II) Crown Complexes

et al. 2021

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Three samarium(II) crown ether complexes, [Sm(15-crown-5)2]I2 (1), [Sm(15-crown-5)2]I2·CH3CN (2), and [Sm(benzo-15-crown-5)2]I2 (3), have been prepared via the reaction of SmI2 with the corresponding crown ether in either THF or acetonitrile in good to moderate yields. The compounds have been characterized by single crystal X-ray diffraction and a variety of spectroscopic techniques. In all cases, the Sm(II) centers are sandwiched between two crown ether molecules and are bound by the five etheric oxygen atoms from each crown ether to yield 10-coordinate environments. Despite the higher symmetry crystal class of 1 (R3c), the samarium center resides on a general position, whereas in 2 and 3 (both in P21/c) the metal centers lie upon inversion centers. Moreover, the complexes in 2 and 3 are approximated well by D 5d symmetry. The molecule in 1, however, is distorted from idealized D 5d symmetry, and the crown ethers are more puckered than observed in 2 and 3. All three complexes luminesce in the NIR at low temperatures. However, the nature of the luminescence differs between the three compounds. 1 exhibits broadband photoluminescence at 20 °C but at low temperatures transitions to narrow peaks. 2 only exhibits nonradiative decay at 20 °C and at low temperatures retains a mixture of broadband and fine transitions. Finally, 3 displays broadband luminescence regardless of temperature. Spin–orbit (SO) CASSCF calculations reveal that the outer-sphere iodide anions influence whether broadband luminescence from 5d → 4f or fine 4f → 4f transitions occur through the alteration of symmetry around the metal centers and the nature of the excited states as a function of temperature.

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Section: ■ Experimental Sectioncontrasting

confidence: 95%

Influence of Outer-Sphere Anions on the Photoluminescence from Samarium(II) Crown Complexes

et al. 2021

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“…Given the difficulty in retaining low metal oxidation states in oxygen-coordination environments, a particularly significant accomplishment was the stabilization of Cf II at low concentration (1%) in crystalline strontium tetraborate, 16 similarly to the stabilization of Sm II doped into alkaline-earth feldspars. 17 The scarcity and high radioactivity of the available isotopes of californium have greatly restricted the development of its chemistry, including discovery of discrete molecular coordination compounds or complexes comprising Cf II . In contrast, there are several reports of divalent Sm complexes, such as metallocenes, [18][19][20] chalcogenates, 21 decaborates, 22 phosphidos, 23 and amides.…”

Section: Introductionmentioning

confidence: 99%

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

et al. 2016

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The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf(II) is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf(II)(CH3SO2)3(-), prepared in the gas phase by reductive elimination of CH3SO2 from Cf(III)(CH3SO2)4(-). Comparison with synthesis of the corresponding Sm and Cm complexes reveals reduction of Cf(III) and Sm(III), and no evidence for reduction of Cm(III). This reflects the comparative 3+/2+ reduction potentials: Cf(3+) (-1.60 V) ≈ Sm(3+) (-1.55 V) ≫ Cm(3+) (-3.7 V). Association of O2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. The new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf(II) coordination complexes and similar chemistry of Cf and Sm.

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“…The Sm‐doped glass shows peaks at 360 and 400 nm. The 400 nm peak is due to the 4f to 5d transition ( 6 H 5/2 to 4 F 5/2 ) of Sm 3+ .…”

Section: Absorbancementioning

confidence: 99%

Luminescence effects in reactive powder sintered silica glasses for radiation sensing

et al. 2018

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Silica glasses doped with rare-earth ions are potential materials for optical fiber radiation detection and dosimetry applications. High sensitivity to radiation requires fibers with large cores that can be reliably fabricated using glass made in a novel process from the reactive powder sintering of silica. The luminescence and dosimetric properties of a range of rare earth-doped silica materials produced using this novel technique are reported here. Radioluminescence and optically stimulated luminescence (OSL) are the fundamental mechanisms enabling radiation detection in optical fibers. It was found that thermoluminescence, radioluminescence, and OSL are observed if the glass contains luminescent transitions in the detection wavelength range. Cerium-and thulium-doped silica glasses were found to be promising candidates for optical fiber dosimetry. Samples showed intense luminescence signals in response to both photo-stimulation and irradiation from alpha and beta sources. OSL results for cerium are three times larger than results for irradiated fluoride phosphate glasses previously tested for dosimetry use. Spectroscopic measurements indicate emission in the 300-500 nm region, suitable for detection with photomultiplier tubes. K E Y W O R D Sluminescence, sensors, fibers

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Effects of changing the M²⁺ cation on the crystal structure and optical properties of divalent samarium-doped MAl₂Si₂O₈ (M = Ca, Sr, Ba)

Abstract: The photoluminescence properties and theoretical analysis of Sm2+ doped MAl2Si2O8 (M = Ca, Sr, Ba) were reported. The theoretical analysis is in good agreement with our experimental results.

Cited by 13 publications

References 30 publications

Influence of Outer-Sphere Anions on the Photoluminescence from Samarium(II) Crown Complexes

Influence of Outer-Sphere Anions on the Photoluminescence from Samarium(II) Crown Complexes

Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii)

Luminescence effects in reactive powder sintered silica glasses for radiation sensing

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