Synthesis and Chemical Reactivity of Tetrahydro[60]fullerene Epoxides with Both Amino and Aryl Addends

Tetrahydro­[60]­fullerene epoxides C₆₀(O)­Ar_<i>n</i>(NR₂)_4–<i>n</i>, <i>n</i> = 1, 2, have been prepared by treating 1,4-adducts C₆₀(OH)­Ph and C₆₀(Tol)₂ with cyclic secondary amines. The epoxy moieties in these mixed tetrahydro[60]­fullerene epoxides were hydrolyzed into the corresponding diol derivatives, which were further oxidized into diketone open-cage fullerenes with a 10-membered orifice. A few other reactions also showed that the present tetrahydro[60]­fullerene epoxides with both amino and aryl addends exhibit improved chemical reactivity over the tetraamino[60]­fullerene epoxide without any aryl group

Synthesis and Chemical Reactivity of Tetrahydro[60]fullerene Epoxides with Both Amino and Aryl Addends

Tetrahydro­[60]­fullerene epoxides C₆₀(O)­Ar_<i>n</i>(NR₂)_4–<i>n</i>, <i>n</i> = 1, 2, have been prepared by treating 1,4-adducts C₆₀(OH)­Ph and C₆₀(Tol)₂ with cyclic secondary amines. The epoxy moieties in these mixed tetrahydro[60]­fullerene epoxides were hydrolyzed into the corresponding diol derivatives, which were further oxidized into diketone open-cage fullerenes with a 10-membered orifice. A few other reactions also showed that the present tetrahydro[60]­fullerene epoxides with both amino and aryl addends exhibit improved chemical reactivity over the tetraamino[60]­fullerene epoxide without any aryl group

Pentafluorophenyl Transfer Reaction: Preparation of Pentafluorophenyl [60]Fullerene Adducts through Opening of Fullerene Epoxide Moiety with Trispentafluorophenylborane

Unlike the extensively studied perfluoroalkyl fullerene adducts, perfluorophenyl fullerene adducts are quite difficult to prepare by known methods. Trispentafluorophenylborane was found to react with fullerene epoxide to form the 1,2-perfluorophenylfullerenol. The method can be applied to both the simple epoxide C₆₀(O) and fullerene multiadducts containing an epoxide moiety. Single crystal X-ray structure analysis confirmed the addition of the pentafluorophenyl group

Influence of Anion/Cation Substitution (Sr²⁺ → Ba²⁺, Al³⁺ → Si⁴⁺, N^3– → O^2–) on Phase Transformation and Luminescence Properties of Ba₃Si₆O₁₅:Eu²⁺ Phosphors

A series of promising cyan, green, and yellow emission (Ba, Sr)₃(Si, Al)₆(O, N)₁₅:Eu²⁺ phosphors were synthesized by a Pechini-type sol–gel ammonolysis method. Variations in luminescence properties and crystal structure caused by the modification of phosphor composition were studied in detail. The prefired temperatures of the precursors play a key role in the process of forming the final products. Under UV light excitation, the as-prepared Ba₃Si₆O₁₅:Eu²⁺ phosphor presents a strong cyan emission located at 498 nm. Moreover, the as-prepared oxynitride phosphors, Eu²⁺-activated (Ba_1–<i>y</i>Sr_<i>y</i>)₃Si_6–<i>x</i>Al_<i>x</i>O_15−μN_δ (<i>x</i> = 0–1.2, <i>y</i> = 0–0.6), display a broader excitation band covering the entire visible region. Under blue light excitation, Ba₃Si_6–<i>x</i>Al_<i>x</i>O_15−μN_δ:Eu²⁺ phosphors show a intense and narrow green emission at 520 nm, and the luminescent intensity can be enhanced by increasing Al content within a certain range. However, (Ba_1–<i>y</i>Sr_<i>y</i>)₃Si₆O_15−μN_δ:Eu²⁺phosphors exhibit green (520 nm) to yellow (554 nm) emission with increasing Sr content. Unexpectedly, Eu²⁺ doped Ba₃Si₆O₉N₄-type Ba₃Si₆O_15−μN_δ–1300 °C phosphor exhibits a bluish green emission and strong thermal quenching behavior. The (Ba_1–<i>y</i>Sr_<i>y</i>)₃Si_6–<i>x</i>Al_<i>x</i>O_15−μN_δ:Eu²⁺ phosphors exhibit a small thermal quenching, and the quantum yields measured under 460 nm excitation could reach up to 89% for green Ba₃Si_6–<i>x</i>Al_<i>x</i>O_15−μN_δ:Eu²⁺ phosphor and 71% for yellow (Ba_1–<i>y</i>Sr_<i>y</i>)₃Si_6<i>x</i>O_15−μN_δ:Eu²⁺ phosphor. White LEDs with tunable color temperature and higher color rendering index were fabricated by combining the prepared cyan Ba₃Si₆O₁₅:Eu²⁺/green Ba_2.91Eu_0.09Si_6–<i>x</i>Al_<i>x</i>O_15−μN_δ (<i>x</i> = 0.06)/yellow (Ba_{0.97–<i>y</i>}Sr_<i>y</i>)₃Eu_0.09Si₆O_15−μN_δ (<i>y</i> = 0.4) phosphor and a red phosphor with a UV or blue LED chip, indicating that they are promising phosphors for white LEDs

Selective Synthesis of Fullerenol Derivatives with Terminal Alkyne and Crown Ether Addends

A series of isomerically pure alkynyl-substituted fullerenol derivatives such as C₆₀(OH)₆(O­(CH₂)₃CCH)₂ were synthesized through Lewis acid catalyzed epoxy ring opening and/or S_N1 replacement reactions starting from the fullerene–mixed peroxide C₆₀(O)­(<i>t</i>-BuOO)₄. Copper-catalyzed azide–alkyne cycloaddition readily converted the terminal alkynyl groups into triazole groups. Intramolecular oxidative alkyne coupling afforded a fullerenyl crown ether derivative

Photoluminescence and Energy Transfer Properties with Y+SiO₄ Substituting Ba+PO₄ in Ba₃Y(PO₄)₃:Ce³⁺/Tb³⁺, Tb³⁺/Eu³⁺ Phosphors for w‑LEDs

A series of Ce³⁺, Tb³⁺, Eu³⁺ doped Ba₂Y₂(PO₄)₂­(SiO₄) (BYSPO) phosphors were synthesized via the high-temperature solid-state reaction route. X-ray diffraction, high-resolution transmission electron microscopy, Fourier transform infrared, solid-state NMR, photoluminescence (PL) including temperature-dependent PL, and fluorescent decay measurements were conducted to characterize and analyze as-prepared samples. BYSPO was obtained by the substitution of Y+SiO₄ for Ba+PO₄ in Ba₃Y­(PO₄)₃ (BYPO). The red shift of PL emission from 375 to 401 nm occurs by comparing BYSPO:0.14Ce³⁺ with BYPO:0.14Ce³⁺ under 323 nm UV excitation. More importantly, the excitation edge can be extended from 350 to 400 nm, which makes it be excited by UV/n-UV chips (330–410 nm). Tunable emission color from blue to green can be observed under 365 nm UV excitation based on the energy transfer from Ce³⁺ to Tb³⁺ ions after codoping Tb³⁺ into BYSPO:0.14Ce³⁺. Moreover, energy transfer from Tb³⁺ to Eu³⁺ ions also can be found in BYSPO:Tb³⁺,Eu³⁺ phosphors, resulting in the tunable color from green to orange red upon 377 nm UV excitation. Energy transfer properties were demonstrated by overlap of excitation spectra, variations of emission spectra, and decay times. In addition, energy transfer mechanisms from Ce³⁺ to Tb³⁺ and Tb³⁺ to Eu³⁺ in BYSPO were also discussed in detail. Quantum yields and CIE chromatic coordinates were also presented. Generally, the results suggest their potential applications in UV/n-UV pumped LEDs

Preparation of a 12-Membered Open-Cage Fullerendione through Silane/Borane-Promoted Formation of Ketal Moieties and Oxidation of a Vicinal Fullerendiol

[60]Fullerene mixed peroxide C60 (OH)(Cl)(OOtBu) reacts with PhMe2SiH/B(C6F5)3 to give oxahomofullerene. Mechanistic investigation indicates that the hydroxyl group in the central pentagon ring is essential to convert the tert-butylperoxo group into a ketal moiety. Migration of the silyl group and transformation of the siloxy group into a phenyl group are observed in the deprotection of the fullerene bound siloxy group. A 12-membered open-cage fullerendione was obtained through oxidation of a [6,6]-fullerendiol. This orifice could be closed to form ketal/hemiketal moieties by BF3-catalyzed reaction with methanol. All of the new fullerene derivatives were characterized by spectroscopic data, and structure of the open-cage fullerendione was also confirmed by single-crystal X-ray analysis

Preparation of a 12-Membered Open-Cage Fullerendione through Silane/Borane-Promoted Formation of Ketal Moieties and Oxidation of a Vicinal Fullerendiol

[60]Fullerene mixed peroxide C60 (OH)(Cl)(OOtBu) reacts with PhMe2SiH/B(C6F5)3 to give oxahomofullerene. Mechanistic investigation indicates that the hydroxyl group in the central pentagon ring is essential to convert the tert-butylperoxo group into a ketal moiety. Migration of the silyl group and transformation of the siloxy group into a phenyl group are observed in the deprotection of the fullerene bound siloxy group. A 12-membered open-cage fullerendione was obtained through oxidation of a [6,6]-fullerendiol. This orifice could be closed to form ketal/hemiketal moieties by BF3-catalyzed reaction with methanol. All of the new fullerene derivatives were characterized by spectroscopic data, and structure of the open-cage fullerendione was also confirmed by single-crystal X-ray analysis

Ultra-broad Near-Infrared Emitting Phosphor LiInF₄: Cr³⁺ with Extremely Weak Crystal Field

Recent decades have witnessed a major development in broadband near-infrared (NIR)-emitting phosphors because of their potential applications in real-time nondestructive examination. These applications require the emission spectra of phosphors to be as broad as possible for efficient performance. Therefore, a blue-light excited LiInF4: Cr3+ phosphor with a NIR emission covering 700–1400 nm is successfully synthesized. Under 470 nm excitation, it shows broadband emission peaked at 980 nm with the full-width at half maximum of 210 nm. The structure and crystal field environment are investigated in detail, and the LiInF4: Cr3+ possesses a weak crystal field strength and strong electron–phonon coupling. An efficient NIR phosphor-converted light-emitting diode (pc-LED) is fabricated by the prepared LiInF4: Cr3+ phosphor and commercial blue diode chip, generating a NIR radiant flux of 5.54 mW at 150 mA drive current. Finally, the NIR pc-LED is successfully applied to identify the blood vessel distribution of the hand. This work suggests the potential of LiInF4: Cr3+ phosphor in applications

Boosting Stability and Inkjet Printability of Pure-Red CsPb(Br/I)₃ Quantum Dots through Dual-Shell Encapsulation for Micro-LED Displays

The development of pure-red perovskite quantum dots (QDs) for displays is lagging due to their structural instability. Herein, we present a new core dual-shell structure with CsPb(Br/I)3@SiO2@polystyrene (PS) QDs, emitting at 627 nm. The structure consists of a CsPb(Br/I)3 core, an intermediate SiO2 layer, and an outermost PS shell. The PS shell plays a crucial role in silane hydrolysis, preventing SiO2 aggregation and enhancing the dispersibility of the CsPb(Br/I)3@SiO2@PS QDs. These QDs exhibit enhanced resilience against irradiation, moisture, and thermal stress, maintaining approximately 80% of their initial photoluminescence (PL) intensity after 3 days of UV irradiation exposure or after 2 days of being subject to high humidity and temperature conditions. Utilized as red inkjet inks, these QDs enable the inkjet printing of a vivid red dot matrix and a Chinese chess pattern. This innovation holds promise for expanding the practical utilization of CsPb(Br/I)3 QDs, particularly in full-color micro-LED display technology via inkjet printing